STM32L031x4, x6 Datasheet by STMicroelectronics

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This is information on a product in full production.
March 2018 DS10668 Rev 6 1/126
STM32L031x4 STM32L031x6
Access line ultra-low-power 32-bit MCU Arm
®
-based
Cortex
®
-M0+, up to 32KB Flash, 8KB SRAM, 1KB EEPROM, ADC
Datasheet - production data
Features
Ultra-low-power platform
1.65 V to 3.6 V power supply
-40 to 125 °C temperature range
0.23 µA Standby mode (2 wakeup pins)
0.35 µA Stop mode (16 wakeup lines)
0.6 µA Stop mode + RTC + 8 KB RAM retention
Down to 76 µA/MHz in Run mode
5 µs wakeup time (from Flash memory)
–41µA
12-bit ADC conversion at 10 ksps
Core: Arm
®
32-bit Cortex
®
-M0+
From 32 kHz up to 32 MHz max.
0.95 DMIPS/MHz
Reset and supply management
Ultra-safe, low-power BOR (brownout reset)
with 5 selectable thresholds
Ultralow power POR/PDR
Programmable voltage detector (PVD)
Clock sources
1 to 25 MHz crystal oscillator
32 kHz oscillator for RTC with calibration
High speed internal 16 MHz factory-trimmed RC
(+/- 1%)
Internal low-power 37 kHz RC
Internal multispeed low-power 65 kHz to
4.2 MHz RC
PLL for CPU clock
Pre-programmed bootloader
USART, SPI supported
Development support
Serial wire debug supported
Up to 38 fast I/Os (31 I/Os 5V tolerant)
Memories
Up to
32-Kbyte Flash with ECC
8-Kbyte RAM
1-Kbyte of data EEPROM with ECC
20-byte backup register
Sector protection against R/W operation
Rich Analog peripherals
12-bit ADC 1.14 Msps up to 10 channels (down
to 1.65 V)
2x ultra-low-power comparators (window mode
and wake up capability, down to 1.65 V)
7-channel DMA controller, supporting ADC, SPI,
I2C, USART, Timers
5x peripherals communication interface
1x USART (ISO 7816, IrDA), 1x UART (low power)
Up to 2 SPI interfaces, up to 16 Mbits/s
1x I2C (SMBus/PMBus)
8x timers: 1x 16-bit with up to 4 channels, 2x 16-bit
with up to 2 channels, 1x 16-bit ultra-low-power
timer, 1x SysTick, 1x RTC and 2x watchdogs
(independent/window)
CRC calculation unit, 96-bit unique ID
All packages are ECOPACK
®
2
Table 1. Device summary
Reference Part number
STM32L031x4
STM32L031G4, STM32L031K4,
STM32L031C4, STM32L031E4,
STM32L031F4
STM32L031x6
STM32L031G6, STM32L031K6,
STM32L031C6, STM32L031E6,
STM32L031F6
UFQFPN28 4x4 mm
UFQFPN32 5x5 mm
UFQFPN48 7x7 mm
LQFP32/48
7x7 mm
WLCSP25
2.097x2.493 mm
TSSOP20
169 mils
www.st.com
Contents STM32L031x4/6
2/126 DS10668 Rev 6
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1 Device overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.2 Ultra-low-power device continuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 Functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1 Low-power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Interconnect matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 Arm® Cortex®-M0+ core . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.4 Reset and supply management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.4.1 Power supply schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.4.2 Power supply supervisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.4.3 Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.4.4 Boot modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.5 Clock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.6 Low-power real-time clock and backup registers . . . . . . . . . . . . . . . . . . . 25
3.7 General-purpose inputs/outputs (GPIOs) . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.8 Extended interrupt/event controller (EXTI) . . . . . . . . . . . . . . . . . . . . . . . . 26
3.9 Memories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.10 Direct memory access (DMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.11 Analog-to-digital converter (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.12 Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.12.1 Internal voltage reference (VREFINT) . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.13 Ultra-low-power comparators and reference voltage . . . . . . . . . . . . . . . . 28
3.14 System configuration controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.15 Timers and watchdogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.15.1 General-purpose timers (TIM2, TIM21 and TIM22) . . . . . . . . . . . . . . . . 29
3.15.2 Low-power timer (LPTIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.15.3 SysTick timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.15.4 Independent watchdog (IWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.15.5 Window watchdog (WWDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
DS10668 Rev 6 3/126
STM32L031x4/6 Contents
4
3.16 Communication interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.16.1 I2C bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.16.2 Universal synchronous/asynchronous receiver transmitter (USART) . . 31
3.16.3 Low-power universal asynchronous receiver transmitter (LPUART) . . . 32
3.16.4 Serial peripheral interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.17 Cyclic redundancy check (CRC) calculation unit . . . . . . . . . . . . . . . . . . . 33
3.18 Serial wire debug port (SW-DP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5 Memory mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1 Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.1 Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.1.6 Power supply scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.1.7 Current consumption measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.3 Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.3.1 General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.3.2 Embedded reset and power control block characteristics . . . . . . . . . . . 53
6.3.3 Embedded internal reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.3.4 Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.3.5 Wakeup time from low-power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.3.6 External clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3.7 Internal clock source characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.3.8 PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.3.9 Memory characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.3.10 EMC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.3.11 Electrical sensitivity characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.3.12 I/O current injection characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.3.13 I/O port characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.3.14 NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Contents STM32L031x4/6
4/126 DS10668 Rev 6
6.3.15 12-bit ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6.3.16 Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
6.3.17 Comparators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
6.3.18 Timer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.3.19 Communications interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.1 LQFP48 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.2 UFQFPN48 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.3 LQFP32 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
7.4 UFQFPN32 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.5 UFQFPN28 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.6 WLCSP25 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112
7.7 TSSOP20 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
7.8 Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
7.8.1 Reference document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
DS10668 Rev 6 5/126
STM32L031x4/6 List of tables
6
List of tables
Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Ultra-low-power STM32L031x4/x6 device features and peripheral counts. . . . . . . . . . . . . 11
Table 3. Functionalities depending on the operating power supply range . . . . . . . . . . . . . . . . . . . . 17
Table 4. CPU frequency range depending on dynamic voltage scaling . . . . . . . . . . . . . . . . . . . . . . 17
Table 5. Functionalities depending on the working mode
(from Run/active down to standby) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 6. STM32L0xx peripherals interconnect matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 7. Temperature sensor calibration values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 8. Internal voltage reference measured values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 9. Timer feature comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 10. Comparison of I2C analog and digital filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 11. STM32L031x4/6 I2C implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 12. USART implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 13. SPI implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 14. Legend/abbreviations used in the pinout table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 15. Pin definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 16. Alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Table 17. Voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 18. Current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Table 19. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Table 20. General operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Table 21. Embedded reset and power control block characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 53
Table 22. Embedded internal reference voltage calibration values . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Table 23. Embedded internal reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Table 24. Current consumption in Run mode, code with data processing running
from Flash memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Table 25. Current consumption in Run mode vs code type,
code with data processing running from Flash memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Table 26. Current consumption in Run mode, code with data processing running from RAM . . . . . . 59
Table 27. Current consumption in Run mode vs code type,
code with data processing running from RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Table 28. Current consumption in Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Table 29. Current consumption in Low-power run mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Table 30. Current consumption in Low-power sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Table 31. Typical and maximum current consumptions in Stop mode . . . . . . . . . . . . . . . . . . . . . . . . 63
Table 32. Typical and maximum current consumptions in Standby mode . . . . . . . . . . . . . . . . . . . . . 64
Table 33. Average current consumption during wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Table 34. Peripheral current consumption in Run or Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Table 35. Peripheral current consumption in Stop and Standby mode . . . . . . . . . . . . . . . . . . . . . . . 66
Table 36. Low-power mode wakeup timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Table 37. High-speed external user clock characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Table 38. Low-speed external user clock characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Table 39. HSE oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 40. LSE oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 41. 16 MHz HSI16 oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Table 42. LSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Table 43. MSI oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Table 44. PLL characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
List of tables STM32L031x4/6
6/126 DS10668 Rev 6
Table 45. RAM and hardware registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Table 46. Flash memory and data EEPROM characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Table 47. Flash memory and data EEPROM endurance and retention . . . . . . . . . . . . . . . . . . . . . . . 76
Table 48. EMS characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Table 49. EMI characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Table 50. ESD absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Table 51. Electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 52. I/O current injection susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 53. I/O static characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Table 54. Output voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Table 55. I/O AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Table 56. NRST pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Table 57. ADC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Table 58. RAIN max for fADC = 16 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Table 59. ADC accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Table 60. Temperature sensor calibration values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Table 61. Temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 62. Comparator 1 characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 63. Comparator 2 characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Table 64. TIMx characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Table 65. I2C analog filter characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Table 66. SPI characteristics in voltage Range 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Table 67. SPI characteristics in voltage Range 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Table 68. SPI characteristics in voltage Range 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Table 69. LQFP48 - 48-pin low-profile quad flat package, 7 x 7 mm, package mechanical data. . . . 98
Table 70. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Table 71. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package mechanical data . . . . . . . . . . . 105
Table 72. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Table 73. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Table 74. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Table 75. WLCSP25 recommended PCB design rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Table 76. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Table 77. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Table 78. STM32L031x4/6 ordering information scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Table 79. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
DS10668 Rev 6 7/126
STM32L031x4/6 List of figures
8
List of figures
Figure 1. STM32L031x4/6 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 2. Clock tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 3. STM32L031x4/6 UFQFPN48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 4. STM32L031x4/6 LQFP48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 5. STM32L031x4/6 LQFP32 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 6. STM32L031x4/6 UFQFPN32 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 7. STM32L031x4/6 UFQFPN28 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 8. STM32L031 UFQFPN28 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 9. STM32L031x4/6 TSSOP20 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 10. STM32L031x4/6 WLCSP25 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 11. Pin loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 12. Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 13. Power supply scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 14. Current consumption measurement scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 15. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from
Flash memory, Range 2, HSE = 16 MHz, 1WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Figure 16. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from
Flash memory, Range 2, HSI16, 1WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Figure 17. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Low-power run mode, code running
from RAM, Range 3, MSI (Range 0) at 64 KHz, 0 WS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 18. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Stop mode with RTC enabled
and running on LSE Low drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Figure 19. IDD vs VDD, at TA= 25/55/85/105/125 °C, Stop mode with RTC disabled,
all clocks off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Figure 20. High-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Figure 21. Low-speed external clock source AC timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 22. HSE oscillator circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Figure 23. Typical application with a 32.768 kHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Figure 24. HSI16 minimum and maximum value versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . 73
Figure 25. VIH/VIL versus VDD (CMOS I/Os) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Figure 26. VIH/VIL versus VDD (TTL I/Os) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Figure 27. I/O AC characteristics definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Figure 28. Recommended NRST pin protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Figure 29. ADC accuracy characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Figure 30. Typical connection diagram using the ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Figure 31. SPI timing diagram - slave mode and CPHA = 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Figure 32. SPI timing diagram - slave mode and CPHA = 1(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Figure 33. SPI timing diagram - master mode(1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Figure 34. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . . 97
Figure 35. LQFP48 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Figure 36. Example of LQFP48 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Figure 37. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Figure 38. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Figure 39. Example of UFQFPN48 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Figure 40. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package outline . . . . . . . . . . . . . . . . . . . 104
Figure 41. LQFP32 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
List of figures STM32L031x4/6
8/126 DS10668 Rev 6
Figure 42. Example of LQFP32 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Figure 43. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Figure 44. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Figure 45. Example of UFQFPN32 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Figure 46. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Figure 47. UFQFPN28 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Figure 48. Example of UFQFPN28 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Figure 49. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Figure 50. WLCSP25 - 2.097 x 2.493 mm, 0.400 mm pitch wafer level chip scale
recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Figure 51. Example of WLCSP25 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Figure 52. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,
package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Figure 53. TSSOP20 – 20-lead thin shrink small outline, 6.5 x 4.4 mm, 0.65 mm pitch,
package footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Figure 54. Example of TSSOP20 marking (package top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Figure 55. Thermal resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
arm
DS10668 Rev 6 9/126
STM32L031x4/6 Introduction
33
1 Introduction
The ultra-low-power STM32L031x4/6 family includes devices in 6 different packages from
20 to 48 pins. The description below gives an overview of the complete range of peripherals
proposed in this family.
These features make the ultra-low-power STM32L031x4/6 microcontrollers suitable for a
wide range of applications:
Gas/water meters and industrial sensors
Healthcare and fitness equipment
Remote control and user interface
PC peripherals, gaming, GPS equipment
Alarm system, wired and wireless sensors, video intercom
This STM32L031x4/6 datasheet must be read in conjunction with the STM32L0x1 reference
manual (RM0377).
For information on the Arm® Cortex
®
-M0+ core please refer to the Cortex
®
-M0+ Technical
Reference Manual, available from the http://www.arm.com website.
Figure 1 shows the general block diagram of the device family.
Description STM32L031x4/6
10/126 DS10668 Rev 6
2 Description
The access line ultra-low-power STM32L031x4/6 family incorporates the high-performance
Arm
®
Cortex
®
-M0+ 32-bit RISC core operating at a 32 MHz frequency, high-speed
embedded memories (up to
32
Kbytes of Flash program memory,
1
Kbytes of data
EEPROM and 8 Kbytes of RAM) plus an extensive range of enhanced I/Os and peripherals.
The STM32L031x4/6 devices provide high power efficiency for a wide range of
performance. It is achieved with a large choice of internal and external clock sources, an
internal voltage adaptation and several low-power modes.
The STM32L031x4/6 devices offer several analog features, one 12-bit ADC with hardware
oversampling, two ultra-low-power comparators, several timers, one low-power timer
(LPTIM), three general-purpose 16-bit timers, one RTC and one SysTick which can be used
as timebases. They also feature two watchdogs, one watchdog with independent clock and
window capability and one window watchdog based on bus clock.
Moreover, the STM32L031x4/6 devices embed standard and advanced communication
interfaces: one I2C, one SPI, one USART, and a low-power UART (LPUART).
The STM32L031x4/6 also include a real-time clock and a set of backup registers that
remain powered in Standby mode.
The ultra-low-power STM32L031x4/6 devices operate from a 1.8 to 3.6 V power supply
(down to 1.65 V at power down) with BOR and from a 1.65 to 3.6 V power supply without
BOR option. They are available in the -40 to +125 °C temperature range. A comprehensive
set of power-saving modes allows the design of low-power applications.
STM32L031x4/6 Description
DS10668 Rev 6 11/126
2.1 Device overview
Table 2. Ultra-low-power STM32L031x4/x6 device features and peripheral counts
Peripheral STM32
L031F4
STM32
L031E4
STM32
L031G4
STM32
L031K4
STM32
L031C4
STM32
L031F6
STM32
L031E6
STM32
L031G6
STM32
L031K6
STM32
L031C6
Flash (Kbytes) 16 32
Data EEPROM (Kbytes) 1
RAM (Kbytes) 8
Timers
General-
purpose 3
LPTIMER 1
RTC/SYSTICK/IWDG/
WWDG 1/1/1/1
Communicati
on interfaces
SPI 2(1)(1)
I2C1
USART 1
LPUART 1
GPIOs 15 20 21(23)(3) 27(2) 38 15 20 21(23)(3) 27(2) 38
Clocks:
HSE(4)/LSE/HSI/MSI/LSI 1/1/1/1/1
12-bit synchronized ADC
Number of channels
1
10
Comparators 2
Max. CPU frequency 32 MHz
Operating voltage 1.8 V to 3.6 V (down to 1.65 V at power-down) with BOR option
1.65 V to 3.6 V without BOR option
Description STM32L031x4/6
12/126 DS10668 Rev 6
Operating temperatures Ambient temperature: –40 to +125 °C
Junction temperature: –40 to +130 °C
Packages TSSOP
20
WLCSP
25
UFQFPN
28
LQFP32,
UFQFPN
32
LQFP48/
UFQFPN
48
TSSOP
20
WLCSP
25
UFQFPN
28
LQFP32,
UFQFPN
32
LQFP48/
UFQFPN
48
1. 1 SPI interface is a USART operating in SPI master mode.
2. LQFP32 has two GPIOs, less than UFQFPN32 (27).
3. 23 GPIOs are available only on STM32L031GxUxS part number.
4. HSE external quartz connexion available only on LQFP48.
Table 2. Ultra-low-power STM32L031x4/x6 device features and peripheral counts (continued)
Peripheral STM32
L031F4
STM32
L031E4
STM32
L031G4
STM32
L031K4
STM32
L031C4
STM32
L031F6
STM32
L031E6
STM32
L031G6
STM32
L031K6
STM32
L031C6
DS10668 Rev 6 13/126
STM32L031x4/6 Description
33
Figure 1. STM32L031x4/6 block diagram
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Description STM32L031x4/6
14/126 DS10668 Rev 6
2.2 Ultra-low-power device continuum
The ultra-low-power family offers a large choice of core and features, from 8-bit proprietary
core up to Arm
®
Cortex
®
-M4, including Arm
®
Cortex
®
-M3 and Arm
®
Cortex
®
-M0+. The
STM32Lx series are the best choice to answer your needs in terms of ultra-low-power
features. The STM32 Ultra-low-power series are the best solution for applications such as
gas/water meter, keyboard/mouse or fitness and healthcare application. Several built-in
features like LCD drivers, dual-bank memory, low-power run mode, operational amplifiers,
128-bit AES, DAC, crystal-less USB and many other definitely help you building a highly
cost optimized application by reducing BOM cost. STMicroelectronics, as a reliable and
long-term manufacturer, ensures as much as possible pin-to-pin compatibility between all
STM8Lx and STM32Lx on one hand, and between all STM32Lx and STM32Fx on the other
hand. Thanks to this unprecedented scalability, your legacy application can be upgraded to
respond to the latest market feature and efficiency requirements.
DS10668 Rev 6 15/126
STM32L031x4/6 Functional overview
33
3 Functional overview
3.1 Low-power modes
The ultra-low-power STM32L031x4/6 supports dynamic voltage scaling to optimize its
power consumption in Run mode. The voltage from the internal low-drop regulator that
supplies the logic can be adjusted according to the system’s maximum operating frequency
and the external voltage supply.
There are three power consumption ranges:
Range 1 (VDD range limited to 1.71-3.6 V), with the CPU running at up to 32 MHz
Range 2 (full VDD range), with a maximum CPU frequency of 16 MHz
Range 3 (full VDD range), with a maximum CPU frequency limited to 4.2 MHz
Seven low-power modes are provided to achieve the best compromise between low-power
consumption, short startup time and available wakeup sources:
Sleep mode
In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can
wake up the CPU when an interrupt/event occurs. Sleep mode power consumption at
16 MHz is about 1 mA with all peripherals off.
Low-power run mode
This mode is achieved with the multispeed internal (MSI) RC oscillator set to the low-
speed clock (max 131 kHz), execution from SRAM or Flash memory, and internal
regulator in low-power mode to minimize the regulator's operating current. In Low-
power run mode, the clock frequency and the number of enabled peripherals are both
limited.
Low-power sleep mode
This mode is achieved by entering Sleep mode with the internal voltage regulator in
low-power mode to minimize the regulator’s operating current. In Low-power sleep
mode, both the clock frequency and the number of enabled peripherals are limited; a
typical example would be to have a timer running at 32 kHz.
When wakeup is triggered by an event or an interrupt, the system reverts to the Run
mode with the regulator on.
Stop mode with RTC
The Stop mode achieves the lowest power consumption while retaining the RAM and
register contents and real time clock. All clocks in the VCORE domain are stopped, the
PLL, MSI RC, HSE and HSI RC oscillators are disabled. The LSE or LSI is still running.
The voltage regulator is in the low-power mode.
Some peripherals featuring wakeup capability can enable the HSI RC during Stop
mode to detect their wakeup condition.
The device can be woken up from Stop mode by any of the EXTI line, in 3.5 µs, the
processor can serve the interrupt or resume the code. The EXTI line source can be any
GPIO. It can be the PVD output, the comparator 1 event or comparator 2 event
Functional overview STM32L031x4/6
16/126 DS10668 Rev 6
(if internal reference voltage is on), it can be the RTC alarm/tamper/timestamp/wakeup
events, the USART/I2C/LPUART/LPTIMER wakeup events.
Stop mode without RTC
The Stop mode achieves the lowest power consumption while retaining the RAM and
register contents. All clocks are stopped, the PLL, MSI RC, HSI and LSI RC, HSE and
LSE crystal oscillators are disabled.
Some peripherals featuring wakeup capability can enable the HSI RC during Stop
mode to detect their wakeup condition.
The voltage regulator is in the low-power mode. The device can be woken up from Stop
mode by any of the EXTI line, in 3.5 µs, the processor can serve the interrupt or
resume the code. The EXTI line source can be any GPIO. It can be the PVD output, the
comparator 1 event or comparator 2 event (if internal reference voltage is on). It can
also be wakened by the USART/I2C/LPUART/LPTIMER wakeup events.
Standby mode with RTC
The Standby mode is used to achieve the lowest power consumption and real time
clock. The internal voltage regulator is switched off so that the entire VCORE domain is
powered off. The PLL, MSI RC, HSE and HSI RC oscillators are also switched off. The
LSE or LSI is still running. After entering Standby mode, the RAM and register contents
are lost except for registers in the Standby circuitry (wakeup logic, IWDG, RTC, LSI,
LSE Crystal 32 KHz oscillator, RCC_CSR register).
The device exits Standby mode in 60 µs when an external reset (NRST pin), an IWDG
reset, a rising edge on one of the three WKUP pins, RTC alarm (Alarm A or Alarm B),
RTC tamper event, RTC timestamp event or RTC Wakeup event occurs.
Standby mode without RTC
The Standby mode is used to achieve the lowest power consumption. The internal
voltage regulator is switched off so that the entire VCORE domain is powered off. The
PLL, MSI RC, HSI and LSI RC, HSE and LSE crystal oscillators are also switched off.
After entering Standby mode, the RAM and register contents are lost except for
registers in the Standby circuitry (wakeup logic, IWDG, RTC, LSI, LSE Crystal 32 KHz
oscillator, RCC_CSR register).
The device exits Standby mode in 60 µs when an external reset (NRST pin) or a rising
edge on one of the three WKUP pin occurs.
Note: The RTC, the IWDG, and the corresponding clock sources are not stopped automatically by
entering Stop or Standby mode.
DS10668 Rev 6 17/126
STM32L031x4/6 Functional overview
33
Table 3. Functionalities depending on the operating power supply range
Operating power supply range(1)
1. GPIO speed depends on VDD voltage range. Refer to Table 55: I/O AC characteristics for more information
about I/O speed.
Functionalities depending on the operating power
supply range
ADC operation Dynamic voltage scaling
range
VDD = 1.65 to 1.71 V Conversion time up to
570 ksps
Range 2 or
range 3
VDD = 1.71 to 2.0 V(2)
2. CPU frequency changes from initial to final must respect the condition: fCPU initial <4fCPU initial. It must also
respect 5 μs delay between two changes. For example to switch from 4.2 MHz to 32 MHz, you can switch
from 4.2 MHz to 16 MHz, wait 5 μs, then switch from 16 MHz to 32 MHz.
Conversion time up to
1.14 Msps Range 1, range 2 or range 3
VDD = 2.0 to 2.4 V Conversion time up to 1.14
Msps Range 1, range 2 or range 3
VDD = 2.4 to 3.6 V Conversion time up to 1.14
Msps Range 1, range 2 or range 3
Table 4. CPU frequency range depending on dynamic voltage scaling
CPU frequency range Dynamic voltage scaling range
16 MHz to 32 MHz (1ws)
32 kHz to 16 MHz (0ws) Range 1
8 MHz to 16 MHz (1ws)
32 kHz to 8 MHz (0ws) Range 2
32 kHz to 4.2 MHz (0ws) Range 3
Table 5. Functionalities depending on the working mode
(from Run/active down to standby) (1)
IPs Run/Active Sleep
Low-
power
run
Low-
power
sleep
Stop Standby
Wakeup
capability
Wakeup
capability
CPU Y -- Y -- -- --
Flash memory O O O O -- --
RAM Y Y Y Y Y --
Backup registers Y Y Y Y Y Y
EEPROM O O O O -- --
Brown-out reset
(BOR) OOOOOOOO
DMA O O O O -- --
Functional overview STM32L031x4/6
18/126 DS10668 Rev 6
Programmable
voltage detector
(PVD)
OOOOOO-
Power-on/down
reset (POR/PDR) YYYYYYYY
High Speed
Internal (HSI) OO----
(2) --
High Speed
External (HSE) OOOO-- --
Low Speed Internal
(LSI) OOOOO O
Low Speed
External (LSE) OOOOO O
Multi-Speed
Internal (MSI) OOYY-- --
Inter-Connect
Controller YYYYY --
RTC O O O O O O O
RTC Tamper O O O O O O O O
Auto WakeUp
(AWU) OOOOOOOO
USART O O O O O(3) O--
LPUART O O O O O(3) O--
SPI O O O O -- --
I2C O O -- -- O(4) O--
ADC O O -- -- -- --
Temperature
sensor OOOOO --
Comparators O O O O O O --
16-bit timers O O O O -- --
LPTIMER O O O O O O
IWDG O O O O O O O O
WWDG O O O O -- --
SysTick Timer O O O O --
GPIOs O O O O O O 2 pins
Table 5. Functionalities depending on the working mode
(from Run/active down to standby) (continued)(1)
IPs Run/Active Sleep
Low-
power
run
Low-
power
sleep
Stop Standby
Wakeup
capability
Wakeup
capability
DS10668 Rev 6 19/126
STM32L031x4/6 Functional overview
33
3.2 Interconnect matrix
Several peripherals are directly interconnected. This allows autonomous communication
between peripherals, thus saving CPU resources and power consumption. In addition,
these hardware connections allow fast and predictable latency.
Depending on peripherals, these interconnections can operate in Run, Sleep, Low-power
run, Low-power sleep and Stop modes.
Wakeup time to
Run mode 0 µs 0.36 µs 3 µs 32 µs 3.5 µs 65 µs
Consumption
VDD=1.8 to 3.6 V
(Typ)
Down to
115 µA/MHz
(from Flash)
Down to
25 µA/MHz
(from Flash)
Down to
6.5 µA
Down to
3.2 µA
0.35 µA (No
RTC) VDD=1.8 V
0.23 µA (No
RTC) VDD=1.8 V
0.6 µA (with
RTC) VDD=1.8 V
0.39 µA (with
RTC) VDD=1.8 V
0.38 µA (No
RTC) VDD=3.0 V
0.26 µA (No
RTC) VDD=3.0 V
0.8 µA (with
RTC) VDD=3.0 V
0.57 µA (with
RTC) VDD=3.0 V
1. Legend:
“Y” = Yes (enable).
“O” = Optional, can be enabled/disabled by software)
“-” = Not available
2. Some peripherals with wakeup from Stop capability can request HSI to be enabled. In this case, HSI is woken up by the
peripheral, and only feeds the peripheral which requested it. HSI is automatically put off when the peripheral does not need
it anymore.
3. UART and LPUART reception is functional in Stop mode. It generates a wakeup interrupt on Start.To generate a wakeup on
address match or received frame event, the LPUART can run on LSE clock while the UART has to wake up or keep running
the HSI clock.
4. I2C address detection is functional in Stop mode. It generates a wakeup interrupt in case of address match. It will wake up
the HSI during reception.
Table 5. Functionalities depending on the working mode
(from Run/active down to standby) (continued)(1)
IPs Run/Active Sleep
Low-
power
run
Low-
power
sleep
Stop Standby
Wakeup
capability
Wakeup
capability
Table 6. STM32L0xx peripherals interconnect matrix
Interconnect
source
Interconnect
destination Interconnect action Run Sleep
Low-
power
run
Low-
power
sleep
Stop
COMPx
TIM2,TIM21,
TIM22
Timer input channel,
trigger from analog
signals comparison
YY Y Y -
LPTIM
Timer input channel,
trigger from analog
signals comparison
YY Y Y Y
TIMx TIMx Timer triggered by other
timer YY Y Y -
Functional overview STM32L031x4/6
20/126 DS10668 Rev 6
3.3 Arm
®
Cortex
®
-M0+ core
The Cortex-M0+ processor is an entry-level 32-bit Arm Cortex processor designed for a
broad range of embedded applications. It offers significant benefits to developers, including:
a simple architecture that is easy to learn and program
ultra-low power, energy-efficient operation
excellent code density
deterministic, high-performance interrupt handling
upward compatibility with Cortex-M processor family
platform security robustness.
The Cortex-M0+ processor is built on a highly area and power optimized 32-bit processor
core, with a 2-stage pipeline von Neumann architecture. The processor delivers exceptional
energy efficiency through a small but powerful instruction set and extensively optimized
design, providing high-end processing hardware including a single-cycle multiplier.
The Cortex-M0+ processor provides the exceptional performance expected of a modern 32-
bit architecture, with a higher code density than other 8-bit and 16-bit microcontrollers.
Owing to its embedded Arm core, the STM32L031x4/6 are compatible with all Arm tools and
software.
RTC
TIM21 Timer triggered by Auto
wake-up YY Y Y -
LPTIM Timer triggered by RTC
event YY Y Y Y
All clock
source TIMx
Clock source used as
input channel for RC
measurement and
trimming
YY Y Y -
GPIO
TIMx Timer input channel and
trigger YY Y Y -
LPTIM Timer input channel and
trigger YY Y Y Y
ADC Conversion trigger Y Y Y Y -
Table 6. STM32L0xx peripherals interconnect matrix (continued)
Interconnect
source
Interconnect
destination Interconnect action Run Sleep
Low-
power
run
Low-
power
sleep
Stop
DS10668 Rev 6 21/126
STM32L031x4/6 Functional overview
33
Nested vectored interrupt controller (NVIC)
The ultra-low-power STM32L031x4/6 embed a nested vectored interrupt controller able to
handle up to 32 maskable interrupt channels and 4 priority levels.
The Cortex-M0+ processor closely integrates a configurable Nested Vectored Interrupt
Controller (NVIC), to deliver industry-leading interrupt performance. The NVIC:
includes a Non-Maskable Interrupt (NMI)
provides zero jitter interrupt option
provides four interrupt priority levels
The tight integration of the processor core and NVIC provides fast execution of Interrupt
Service Routines (ISRs), dramatically reducing the interrupt latency. This is achieved
through the hardware stacking of registers, and the ability to abandon and restart load-
multiple and store-multiple operations. Interrupt handlers do not require any assembler
wrapper code, removing any code overhead from the ISRs. Tail-chaining optimization also
significantly reduces the overhead when switching from one ISR to another.
To optimize low-power designs, the NVIC integrates with the sleep modes, that include a
deep sleep function that enables the entire device to enter rapidly stop or standby mode.
This hardware block provides flexible interrupt management features with minimal interrupt
latency.
3.4 Reset and supply management
3.4.1 Power supply schemes
VDD = 1.65 to 3.6 V: external power supply for I/Os and the internal regulator. Provided
externally through VDD pins.
VSSA, VDDA = 1.65 to 3.6 V: external analog power supplies for ADC, reset blocks, RCs
and PLL. VDDA and VSSA must be connected to VDD and VSS, respectively.
3.4.2 Power supply supervisor
The devices feature an integrated ZEROPOWER power-on reset (POR)/power-down reset
(PDR) that can be coupled with a brownout reset (BOR) circuitry.
Two versions are available:
The version with BOR activated at power-on operates between 1.8 V and 3.6 V.
The other version without BOR operates between 1.65 V and 3.6 V.
After the VDD threshold is reached (1.65 V or 1.8 V depending on the BOR which is active or
not at power-on), the option byte loading process starts, either to confirm or modify default
thresholds, or to disable the BOR permanently: in this case, the VDD min value becomes
1.65 V (whatever the version, BOR active or not, at power-on).
When BOR is active at power-on, it ensures proper operation starting from 1.8 V whatever
the power ramp-up phase before it reaches 1.8 V. When BOR is not active at power-up, the
power ramp-up must guarantee that 1.65 V is reached on VDD at least 1 ms after it exits the
POR area.
Five BOR thresholds are available through option bytes, starting from 1.8 V to 3 V. To
reduce the power consumption in Stop mode, it is possible to automatically switch off the
Functional overview STM32L031x4/6
22/126 DS10668 Rev 6
internal reference voltage (VREFINT) in Stop mode. The device remains in reset mode when
VDD is below a specified threshold, VPOR/PDR or VBOR, without the need for any external
reset circuit.
Note: The start-up time at power-on is typically 3.3 ms when BOR is active at power-up, the start-
up time at power-on can be decreased down to 1 ms typically for devices with BOR inactive
at power-up.
The devices feature an embedded programmable voltage detector (PVD) that monitors the
VDD/VDDA power supply and compares it to the VPVD threshold. This PVD offers 7 different
levels between 1.85 V and 3.05 V, chosen by software, with a step around 200 mV. An
interrupt can be generated when VDD/VDDA drops below the VPVD threshold and/or when
VDD/VDDA is higher than the VPVD threshold. The interrupt service routine can then generate
a warning message and/or put the MCU into a safe state. The PVD is enabled by software.
3.4.3 Voltage regulator
The regulator has three operation modes: main (MR), low power (LPR) and power down.
MR is used in Run mode (nominal regulation)
LPR is used in the Low-power run, Low-power sleep and Stop modes
Power down is used in Standby mode. The regulator output is high impedance, the
kernel circuitry is powered down, inducing zero consumption but the contents of the
registers and RAM are lost except for the standby circuitry (wakeup logic, IWDG, RTC,
LSI, LSE crystal 32 KHz oscillator, RCC_CSR).
3.4.4 Boot modes
At startup, BOOT0 pin and nBOOT1 option bit are used to select one of three boot options:
Boot from Flash memory
Boot from System memory
Boot from embedded RAM
The boot loader is located in System memory. It is used to reprogram the Flash memory by
using SPI1 (PA4, PA5, PA6, PA7), USART2 (PA2, PA3) or USART2 (PA9, PA10). See
STM32™ microcontroller system memory boot mode AN2606 for details.
DS10668 Rev 6 23/126
STM32L031x4/6 Functional overview
33
3.5 Clock management
The clock controller distributes the clocks coming from different oscillators to the core and
the peripherals. It also manages clock gating for low-power modes and ensures clock
robustness. It features:
Clock prescaler
To get the best trade-off between speed and current consumption, the clock frequency
to the CPU and peripherals can be adjusted by a programmable prescaler.
Safe clock switching
Clock sources can be changed safely on the fly in Run mode through a configuration
register.
Clock management
To reduce power consumption, the clock controller can stop the clock to the core,
individual peripherals or memory.
System clock source
Three different clock sources can be used to drive the master clock SYSCLK:
1-25 MHz high-speed external (HSE), that can supply a PLL
16 MHz high-speed internal RC oscillator (HSI), trimmable by software, that can
supply a PLL
Multispeed internal RC oscillator (MSI), trimmable by software, able to generate 7
frequencies (65 kHz, 131 kHz, 262 kHz, 524 kHz, 1.05 MHz, 2.1 MHz, 4.2 MHz).
When a 32.768 kHz clock source is available in the system (LSE), the MSI
frequency can be trimmed by software down to a ±0.5% accuracy.
Auxiliary clock source
Two ultra-low-power clock sources that can be used to drive the real-time clock:
32.768 kHz low-speed external crystal (LSE)
37 kHz low-speed internal RC (LSI), also used to drive the independent watchdog.
The LSI clock can be measured using the high-speed internal RC oscillator for
greater precision.
RTC clock sources
The LSI, LSE or HSE sources can be chosen to clock the RTC, whatever the system
clock.
Startup clock
After reset, the microcontroller restarts by default with an internal 2 MHz clock (MSI).
The prescaler ratio and clock source can be changed by the application program as
soon as the code execution starts.
Clock security system (CSS)
This feature can be enabled by software. If an HSE clock failure occurs, the master
clock is automatically switched to HSI and a software interrupt is generated if enabled.
Another clock security system can be enabled, in case of failure of the LSE it provides
an interrupt or wakeup event which is generated if enabled.
Clock-out capability (MCO: microcontroller clock output)
It outputs one of the internal clocks for external use by the application.
Several prescalers allow the configuration of the AHB frequency, each APB (APB1 and
APB2) domains. The maximum frequency of the AHB and the APB domains is 32 MHz. See
Figure 2 for details on the clock tree.
Functional overview STM32L031x4/6
24/126 DS10668 Rev 6
Figure 2. Clock tree
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DS10668 Rev 6 25/126
STM32L031x4/6 Functional overview
33
3.6 Low-power real-time clock and backup registers
The real time clock (RTC) and the 5 backup registers are supplied in all modes including
standby mode. The backup registers are five 32-bit registers used to store 20 bytes of user
application data. They are not reset by a system reset, or when the device wakes up from
Standby mode.
The RTC is an independent BCD timer/counter. Its main features are the following:
Calendar with subsecond, seconds, minutes, hours (12 or 24 format), week day, date,
month, year, in BCD (binary-coded decimal) format
Automatically correction for 28, 29 (leap year), 30, and 31 day of the month
Two programmable alarms with wake up from Stop and Standby mode capability
Periodic wakeup from Stop and Standby with programmable resolution and period
On-the-fly correction from 1 to 32767 RTC clock pulses. This can be used to
synchronize it with a master clock.
Reference clock detection: a more precise second source clock (50 or 60 Hz) can be
used to enhance the calendar precision.
Digital calibration circuit with 1 ppm resolution, to compensate for quartz crystal
inaccuracy
2 anti-tamper detection pins with programmable filter. The MCU can be woken up from
Stop and Standby modes on tamper event detection.
Timestamp feature which can be used to save the calendar content. This function can
be triggered by an event on the timestamp pin, or by a tamper event. The MCU can be
woken up from Stop and Standby modes on timestamp event detection.
The RTC clock sources can be:
A 32.768 kHz external crystal
A resonator or oscillator
The internal low-power RC oscillator (typical frequency of 37 kHz)
The high-speed external clock
3.7 General-purpose inputs/outputs (GPIOs)
Each of the GPIO pins can be configured by software as output (push-pull or open-drain), as
input (with or without pull-up or pull-down) or as peripheral alternate function. Most of the
GPIO pins are shared with digital or analog alternate functions, and can be individually
remapped using dedicated alternate function registers. All GPIOs are high current capable.
Each GPIO output, speed can be slowed (40 MHz, 10 MHz, 2 MHz, 400 kHz). The alternate
function configuration of I/Os can be locked if needed following a specific sequence in order
to avoid spurious writing to the I/O registers. The I/O controller is connected to a dedicated
IO bus with a toggling speed of up to 32 MHz.
Functional overview STM32L031x4/6
26/126 DS10668 Rev 6
3.8 Extended interrupt/event controller (EXTI)
The extended interrupt/event controller consists of 26 edge detector lines used to generate
interrupt/event requests. Each line can be individually configured to select the trigger event
(rising edge, falling edge, both) and can be masked independently. A pending register
maintains the status of the interrupt requests. The EXTI can detect an external line with a
pulse width shorter than the Internal APB2 clock period. Up to 38 GPIOs can be connected
to the 16 configurable interrupt/event lines. The 10 other lines are connected to PVD, RTC,
USART, I2C, LPUART, LPTIMER or comparator events.
3.9 Memories
The STM32L031x4/6 devices have the following features:
8 Kbytes of embedded SRAM accessed (read/write) at CPU clock speed with 0 wait
states. With the enhanced bus matrix, operating the RAM does not lead to any
performance penalty during accesses to the system bus (AHB and APB buses).
The non-volatile memory is divided into three arrays:
16 or 32 Kbytes of embedded Flash program memory
1 Kbytes of data EEPROM
Information block containing 32 user and factory options bytes plus 4 Kbytes of
system memory
The user options bytes are used to write-protect or read-out protect the memory (with 4-
Kbyte granularity) and/or readout-protect the whole memory with the following options:
Level 0: no protection
Level 1: memory readout protected.
The Flash memory cannot be read from or written to if either debug features are
connected or boot in RAM is selected
Level 2: chip readout protected, debug features (Cortex-M0+ serial wire) and boot in
RAM selection disabled (debugline fuse)
The whole non-volatile memory embeds the error correction code (ECC) feature.
3.10 Direct memory access (DMA)
The flexible 7-channel, general-purpose DMA is able to manage memory-to-memory,
peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports
circular buffer management, avoiding the generation of interrupts when the controller
reaches the end of the buffer.
Each channel is connected to dedicated hardware DMA requests, with software trigger
support for each channel. Configuration is done by software and transfer sizes between
source and destination are independent.
The DMA can be used with the main peripherals: SPI, I2C, USART, LPUART,
general-purpose timers, and ADC.
DS10668 Rev 6 27/126
STM32L031x4/6 Functional overview
33
3.11 Analog-to-digital converter (ADC)
A native 12-bit, extended to 16-bit through hardware oversampling, analog-to-digital
converter is embedded into STM32L031x4/6 devices. It has up to 10 external channels and
3 internal channels (temperature sensor, voltage reference). Three channel are fast
channel, PA0, PA4 and PA5, while the others are standard channels.
It performs conversions in single-shot or scan mode. In scan mode, automatic conversion is
performed on a selected group of analog inputs.
The ADC frequency is independent from the CPU frequency, allowing maximum sampling
rate of 1.14 Msps even with a low CPU speed. The ADC consumption is low at all
frequencies (~25 µA at 10 kSPS, ~200 µA at 1 Msps). An auto-shutdown function
guarantees that the ADC is powered off except during the active conversion phase.
The ADC can be served by the DMA controller. It can operate from a supply voltage down to
1.65 V.
The ADC features a hardware oversampler up to 256 samples, this improves the resolution
to 16 bits (see AN2668).
An analog watchdog feature allows very precise monitoring of the converted voltage of one,
some or all scanned channels. An interrupt is generated when the converted voltage is
outside the programmed thresholds.
The events generated by the general-purpose timers (TIMx) can be internally connected to
the ADC start triggers, to allow the application to synchronize A/D conversions and timers.
3.12 Temperature sensor
The temperature sensor (TSENSE) generates a voltage VSENSE that varies linearly with
temperature.
The temperature sensor is internally connected to the ADC_IN18 input channel which is
used to convert the sensor output voltage into a digital value.
The sensor provides good linearity but it has to be calibrated to obtain good overall
accuracy of the temperature measurement. As the offset of the temperature sensor varies
from chip to chip due to process variation, the uncalibrated internal temperature sensor is
suitable for applications that detect temperature changes only.
To improve the accuracy of the temperature sensor measurement, each device is
individually factory-calibrated by ST. The temperature sensor factory calibration data are
stored by ST in the system memory area, accessible in read-only mode.
Table 7. Temperature sensor calibration values
Calibration value name Description Memory address
TSENSE_CAL1 TS ADC raw data acquired at
temperature of 30 °C, VDDA= 3 V 0x1FF8 007A - 0x1FF8 007B
TSENSE_CAL2 TS ADC raw data acquired at
temperature of 130 °C, VDDA= 3 V 0x1FF8 007E - 0x1FF8 007F
Functional overview STM32L031x4/6
28/126 DS10668 Rev 6
3.12.1 Internal voltage reference (VREFINT)
The internal voltage reference (VREFINT) provides a stable (bandgap) voltage output for the
ADC and Comparators. VREFINT is internally connected to the ADC_IN17 input channel. It
enables accurate monitoring of the VDD value (since no external voltage, VREF+, is available
for ADC). The precise voltage of VREFINT is individually measured for each part by ST during
production test and stored in the system memory area. It is accessible in read-only mode.
3.13 Ultra-low-power comparators and reference voltage
The STM32L031x4/6 embed two comparators sharing the same current bias and reference
voltage. The reference voltage can be internal or external (coming from an I/O).
One comparator with ultra low consumption
One comparator with rail-to-rail inputs, fast or slow mode.
The threshold can be one of the following:
External I/O pins
Internal reference voltage (VREFINT)
submultiple of Internal reference voltage(1/4, 1/2, 3/4) for the rail to rail
comparator.
Both comparators can wake up the devices from Stop mode, and be combined into a
window comparator.
The internal reference voltage is available externally via a low-power / low-current output
buffer (driving current capability of 1 µA typical).
3.14 System configuration controller
The system configuration controller provides the capability to remap some alternate
functions on different I/O ports.
The highly flexible routing interface allows the application firmware to control the routing of
different I/Os to the TIM2, TIM21, TIM22 and LPTIM timer input captures. It also controls the
routing of internal analog signals to the ADC, COMP1 and COMP2 and the internal
reference voltage VREFINT
.
Table 8. Internal voltage reference measured values
Calibration value name Description Memory address
VREFINT_CAL
Raw data acquired at
temperature of 25 °C
VDDA = 3 V
0x1FF8 0078 - 0x1FF8 0079
DS10668 Rev 6 29/126
STM32L031x4/6 Functional overview
33
3.15 Timers and watchdogs
The ultra-low-power STM32L031x4/6 devices include three general-purpose timers, one
low- power timer (LPTM), two watchdog timers and the SysTick timer.
Table 9 compares the features of the general-purpose and basic timers.
3.15.1 General-purpose timers (TIM2, TIM21 and TIM22)
There are three synchronizable general-purpose timers embedded in the STM32L031x4/6
devices (see Table 9 for differences).
TIM2
TIM2 is based on 16-bit auto-reload up/down counter. It includes a 16-bit prescaler. It
features four independent channels each for input capture/output compare, PWM or one-
pulse mode output.
The TIM2 general-purpose timers can work together or with the TIM21 and TIM22 general-
purpose timers via the Timer Link feature for synchronization or event chaining. Their
counter can be frozen in debug mode. Any of the general-purpose timers can be used to
generate PWM outputs.
TIM2 has independent DMA request generation.
This timer is capable of handling quadrature (incremental) encoder signals and the digital
outputs from 1 to 3 hall-effect sensors.
TIM21 and TIM22
TIM21 and TIM22 are based on a 16-bit auto-reload up/down counter. They include a 16-bit
prescaler. They have two independent channels for input capture/output compare, PWM or
one-pulse mode output. They can work together and be synchronized with the TIM2, full-
featured general-purpose timers.
They can also be used as simple time bases and be clocked by the LSE clock source
(32.768 kHz) to provide time bases independent from the main CPU clock.
Table 9. Timer feature comparison
Timer Counter
resolution Counter type Prescaler factor
DMA
request
generation
Capture/compare
channels
Complementary
outputs
TIM2 16-bit Up, down,
up/down
Any integer between
1 and 65536 Yes 4 No
TIM21,
TIM22 16-bit Up, down,
up/down
Any integer between
1 and 65536 No 2 No
Functional overview STM32L031x4/6
30/126 DS10668 Rev 6
3.15.2 Low-power timer (LPTIM)
The low-power timer has an independent clock and is running also in Stop mode if it is
clocked by LSE, LSI or an external clock. It is able to wakeup the devices from Stop mode.
This low-power timer supports the following features:
16-bit up counter with 16-bit autoreload register
16-bit compare register
Configurable output: pulse, PWM
Continuous / one shot mode
Selectable software / hardware input trigger
Selectable clock source
Internal clock source: LSE, LSI, HSI or APB clock
External clock source over LPTIM input (working even with no internal clock
source running, used by the Pulse Counter Application)
Programmable digital glitch filter
Encoder mode
3.15.3 SysTick timer
This timer is dedicated to the OS, but could also be used as a standard downcounter. It is
based on a 24-bit downcounter with autoreload capability and a programmable clock
source. It features a maskable system interrupt generation when the counter reaches ‘0’.
3.15.4 Independent watchdog (IWDG)
The independent watchdog is based on a 12-bit downcounter and 8-bit prescaler. It is
clocked from an independent 37 kHz internal RC and, as it operates independently of the
main clock, it can operate in Stop and Standby modes. It can be used either as a watchdog
to reset the device when a problem occurs, or as a free-running timer for application timeout
management. It is hardware- or software-configurable through the option bytes. The counter
can be frozen in debug mode.
3.15.5 Window watchdog (WWDG)
The window watchdog is based on a 7-bit downcounter that can be set as free-running. It
can be used as a watchdog to reset the device when a problem occurs. It is clocked from
the main clock. It has an early warning interrupt capability and the counter can be frozen in
debug mode.
DS10668 Rev 6 31/126
STM32L031x4/6 Functional overview
33
3.16 Communication interfaces
3.16.1 I2C bus
One I2C interface (I2C1) can operate in multimaster or slave modes. The I2C interface can
support Standard mode (Sm, up to 100 kbit/s), Fast mode (Fm, up to 400 kbit/s) and Fast
Mode Plus (Fm+, up to 1 Mbit/s) with 20 mA output drive on some I/Os.
The I2C interface supports 7-bit and 10-bit addressing modes, multiple 7-bit slave
addresses (2 addresses, 1 with configurable mask). They also include programmable
analog and digital noise filters.
In addition, I2C1 provides hardware support for SMBus 2.0 and PMBus 1.1: ARP capability,
Host notify protocol, hardware CRC (PEC) generation/verification, timeouts verifications and
ALERT protocol management. I2C1 also has a clock domain independent from the CPU
clock, allowing the I2C1 to wake up the MCU from Stop mode on address match.
The I2C interface can be served by the DMA controller.
Refer to Table 11 for the supported modes and features of I2C interface.
Table 10. Comparison of I2C analog and digital filters
Analog filter Digital filter
Pulse width of
suppressed spikes 50 ns Programmable length from 1 to 15
I2C peripheral clocks
Benefits Available in Stop mode
1. Extra filtering capability vs.
standard requirements.
2. Stable length
Drawbacks Variations depending on
temperature, voltage, process
Wakeup from Stop on address
match is not available when digital
filter is enabled.
Table 11. STM32L031x4/6 I2C implementation
I2C features(1)
1. X = supported.
I2C1
7-bit addressing mode X
10-bit addressing mode X
Standard mode (up to 100 kbit/s) X
Fast mode (up to 400 kbit/s) X
Fast Mode Plus with 20 mA output drive I/Os (up to 1 Mbit/s) X(2)
2. See Table 15: Pin definitions on page 39 for the list of I/Os that feature Fast Mode Plus capability
Independent clock X
SMBus X
Wakeup from STOP X
Functional overview STM32L031x4/6
32/126 DS10668 Rev 6
3.16.2 Universal synchronous/asynchronous receiver transmitter (USART)
The USART interface (USART2) is able to communicate at speeds of up to 4 Mbit/s.
it provides hardware management of the CTS, RTS and RS485 driver enable (DE) signals,
multiprocessor communication mode, master synchronous communication and single-wire
half-duplex communication mode. USART2 also supports Smartcard communication (ISO
7816), IrDA SIR ENDEC, LIN Master/Slave capability, auto baud rate feature and has a
clock domain independent from the CPU clock that allows to wake up the MCU from Stop
mode using baudrates up to 42 Kbaud.
USART2 interface can be served by the DMA controller.
Table 12 for the supported modes and features of USART interface.
3.16.3 Low-power universal asynchronous receiver transmitter (LPUART)
The devices embed one Low-power UART. The LPUART supports asynchronous serial
communication with minimum power consumption. It supports half duplex single wire
communication and modem operations (CTS/RTS). It allows multiprocessor
communication.
The LPUART has a clock domain independent from the CPU clock, and can wake up the
system from Stop mode using baudrates up to 46 Kbaud. The Wakeup events from Stop
mode are programmable and can be:
Start bit detection
Or any received data frame
Or a specific programmed data frame
Only a 32.768 kHz clock (LSE) is needed to allow LPUART communication up to 9600
baud. Therefore, even in Stop mode, the LPUART can wait for an incoming frame while
Table 12. USART implementation
USART modes/features(1)
1. X = supported.
USART2
Hardware flow control for modem X
Continuous communication using DMA X
Multiprocessor communication X
Synchronous mode(2)
2. This mode allows using the USART as an SPI master.
X
Smartcard mode X
Single-wire half-duplex communication X
IrDA SIR ENDEC block X
LIN mode X
Dual clock domain and wakeup from Stop mode X
Receiver timeout interrupt X
Modbus communication X
Auto baud rate detection (4 modes) X
Driver Enable X
DS10668 Rev 6 33/126
STM32L031x4/6 Functional overview
33
having an extremely low energy consumption. Higher speed clock can be used to reach
higher baudrates.
LPUART interface can be served by the DMA controller.
3.16.4 Serial peripheral interface (SPI)
The SPI is able to communicate at up to 16 Mbits/s in slave and master modes in full-duplex
and half-duplex communication modes. The 3-bit prescaler gives 8 master mode
frequencies and the frame is configurable to 8 bits or 16 bits. The hardware CRC
generation/verification supports basic SD Card/MMC modes.
The USARTs with synchronous capability can also be used as SPI master.
The SPI can be served by the DMA controller.
Refer to Table 13 for the supported modes and features of SPI interface.
3.17 Cyclic redundancy check (CRC) calculation unit
The CRC (cyclic redundancy check) calculation unit is used to get a CRC code using a
configurable generator polynomial value and size.
Among other applications, CRC-based techniques are used to verify data transmission or
storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of
verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of
the software during runtime, to be compared with a reference signature generated at
linktime and stored at a given memory location.
3.18 Serial wire debug port (SW-DP)
An Arm SW-DP interface is provided to allow a serial wire debugging tool to be connected to
the MCU.
Table 13. SPI implementation
SPI features(1)
1. X = supported.
SPI1
Hardware CRC calculation X
I2S mode -
TI mode X
Pin descriptions STM32L031x4/6
34/126 DS10668 Rev 6
4 Pin descriptions
Figure 3. STM32L031x4/6 UFQFPN48
1. The above figure shows the package top view.
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DS10668 Rev 6 35/126
STM32L031x4/6 Pin descriptions
46
Figure 4. STM32L031x4/6 LQFP48
1. The above figure shows the package bump view.
Figure 5. STM32L031x4/6 LQFP32 pinout
1. The above figure shows the package top view.
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Pin descriptions STM32L031x4/6
36/126 DS10668 Rev 6
Figure 6. STM32L031x4/6 UFQFPN32 pinout
1. The above figure shows the package top view.
Figure 7. STM32L031x4/6 UFQFPN28 pinout
1. The above figure shows the package top view.
2. This pinout applies to all part numbers except for STM32L031GxUxS .
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DS10668 Rev 6 37/126
STM32L031x4/6 Pin descriptions
46
Figure 8. STM32L031 UFQFPN28 pinout
1. The above figure shows the package top view.
2. This pinout applies only to STM32L031GxUxS part number.
Figure 9. STM32L031x4/6 TSSOP20 pinout
1. The above figure shows the package top view.
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Pin descriptions STM32L031x4/6
38/126 DS10668 Rev 6
Figure 10. STM32L031x4/6 WLCSP25 pinout
1. The above figure shows the package top view.
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Table 14. Legend/abbreviations used in the pinout table
Name Abbreviation Definition
Pin name Unless otherwise specified in brackets below the pin name, the pin function during
and after reset is the same as the actual pin name
Pin type
S Supply pin
I Input only pin
I/O Input / output pin
I/O structure
FT 5 V tolerant I/O
FTf 5 V tolerant I/O, FM+ capable
TC Standard 3.3V I/O
B Dedicated BOOT0 pin
RST Bidirectional reset pin with embedded weak pull-up resistor
Notes Unless otherwise specified by a note, all I/Os are set as floating inputs during and
after reset.
Pin functions
Alternate
functions Functions selected through GPIOx_AFR registers
Additional
functions Functions directly selected/enabled through peripheral registers
DS10668 Rev 6 39/126
STM32L031x4/6 Pin descriptions
46
Table 15. Pin definitions
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
------22 PC13-
ANTI_TAMP I/O FT - - TAMP1/WKUP2
2B5222233 PC14-
OSC32_IN I/O TC - - OSC32_IN
3C5333344
PC15-
OSC32_OU
T
I/O TC - - OSC32_OUT
------55 PH0-
OSC_IN I/O TC - - -
------66 PH1-
OSC_OUT I/O TC - - -
4D5444477 NRST I/O- - - -
------11 PC0 I/OFT-
LPTIM1_IN1,
EVENTOUT,
LPUART1_RX
-
- E1 - - - "0" 8 8 VSSA S - - - -
5C4555599 VDDA S - - - -
6 E5 6 6 6 6 - - PA0-CK_IN I/O TC -
LPTIM1_IN1,
TIM2_CH1,
USART2_CTS,
TIM2_ETR,
COMP1_OUT
COMP1_INM6,
ADC_IN0,
RTC_TAMP2/WKUP1
- - - - - - 10 10 PA0 I/O TC -
LPTIM1_IN1,
TIM2_CH1,
USART2_CTS,
TIM2_ETR,
COMP1_OUT
COMP1_INM6,
ADC_IN0,
RTC_TAMP2/WKUP1
Pin descriptions STM32L031x4/6
40/126 DS10668 Rev 6
7B4 7 7 7 7 1111 PA1 I/OFT -
EVENTOUT,
LPTIM1_IN2,
TIM2_CH2,
I2C1_SMBA,
USART2_RTS/
USART2_DE,
TIM21_ETR
COMP1_INP,
ADC_IN1
8D4 8 8 8 8 1212 PA2 I/OTC -
TIM21_CH1,
TIM2_CH3,
USART2_TX,
LPUART1_TX,
COMP2_OUT
COMP2_INM6,
ADC_IN2,
RTC_TAMP3/RTC_TS
/RTC_OUT/WKUP3
9E4 9 9 9 9 1313 PA3 I/OFT -
TIM21_CH2,
TIM2_CH4,
USART2_RX,
LPUART1_RX
COMP2_INP,
ADC_IN3
10 B3 10 10 10 10 14 14 PA4 I/O TC -
SPI1_NSS,
LPTIM1_IN1,
USART2_CK,
TIM22_ETR
COMP1_INM4,
COMP2_INM4,
ADC_IN4
11 D3 11 11 11 11 15 15 PA5 I/O TC -
SPI1_SCK,
LPTIM1_IN2,
TIM2_ETR,
TIM2_CH1
COMP1_INM5,
COMP2_INM5,
ADC_IN5
12 E3 12 12 12 12 16 16 PA6 I/O FT -
SPI1_MISO,
LPTIM1_ETR,
LPUART1_CTS,
TIM22_CH1,
EVENTOUT,
COMP1_OUT
ADC_IN6
Table 15. Pin definitions (continued)
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
DS10668 Rev 6 41/126
STM32L031x4/6 Pin descriptions
46
13 C3 13 13 13 13 17 17 PA7 I/O FT -
SPI1_MOSI,
LPTIM1_OUT,
USART2_CTS,
TIM22_CH2,
EVENTOUT,
COMP2_OUT
ADC_IN7
- E2141414141818 PB0 I/O FT -
EVENTOUT,
SPI1_MISO,
USART2_RTS/
USART2_DE,
TIM2_CH3
ADC_IN8, VREF_OUT
14 D2 15 15 15 15 19 19 PB1 I/O FT -
USART2_CK,
SPI1_MOSI,
LPUART1_RTS/
LPUART1_DE,
TIM2_CH4
ADC_IN9, VREF_OUT
- - - - - 162020 PB2 I/O FT - LPTIM1_OUT -
- - - - - - 21 21 PB10 I/O FT - TIM2_CH3,
LPUART1_TX -
- - - - - - 22 22 PB11 I/O FT -
EVENTOUT,
TIM2_CH4,
LPUART1_RX
-
15 - 16 16 16 - 23 23 VSS S - - - -
16 - 171717172424 VDD S - - - -
- - - - - - 25 25 PB12 I/O FT - SPI1_NSS,
EVENTOUT -
Table 15. Pin definitions (continued)
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
Pin descriptions STM32L031x4/6
42/126 DS10668 Rev 6
- - - - - - 26 26 PB13 I/O FT -
SPI1_SCK,
MCO,
TIM21_CH1,
LPUART1_CTS
-
- - - - - - 27 27 PB14 I/O FT -
SPI1_MISO,
RTC_OUT,
TIM21_CH2,
LPUART1_RTS/
LPUART1_DE
-
- - - - - - 28 28 PB15 I/O FT - SPI1_MOSI,
RTC_REFIN -
- C1181818182929 PA8 I/O FT -
MCO,
LPTIM1_IN1,
EVENTOUT,
USART2_CK,
TIM2_CH1
-
17 B1 19 19 19 19 30 30 PA9 I/O FTf -
MCO,
I2C1_SCL,
USART2_TX,
TIM22_CH1
-
18 C2 20 20 20 20 31 31 PA10 I/O FTf -
I2C1_SDA,
USART2_RX,
TIM22_CH2
-
- - - - 21 21 32 32 PA11 I/O FT -
SPI1_MISO,
EVENTOUT,
USART2_CTS,
TIM21_CH2,
COMP1_OUT
-
Table 15. Pin definitions (continued)
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
DS10668 Rev 6 43/126
STM32L031x4/6 Pin descriptions
46
- - - - 22 22 33 33 PA12 I/O FT -
SPI1_MOSI,
EVENTOUT,
USART2_RTS/
USART2_DE,
COMP2_OUT
-
19 A1 21 21 23 23 34 34 PA13 I/O FT -
SWDIO,
LPTIM1_ETR,
LPUART1_RX
-
- - - - - - 35 35 VSS S - - - -
-D1 - - - - 3636 VDD S - - - -
20 A2 22 22 24 24 37 37 PA14 I/O FT -
SWCLK,
LPTIM1_OUT,
I2C1_SMBA,
USART2_TX,
LPUART1_TX
-
- - 23 23 25 25 38 38 PA15 I/O FT -
SPI1_NSS,
TIM2_ETR,
EVENTOUT,
USART2_RX,
TIM2_CH1
--
- B2242426263939 PB3 I/O FT -
SPI1_SCK,
TIM2_CH2,
EVENTOUT
COMP2_INN
- - - 2527274040 PB4 I/O FT -
SPI1_MISO,
EVENTOUT,
TIM22_CH1
COMP2_INP
Table 15. Pin definitions (continued)
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
Pin descriptions STM32L031x4/6
44/126 DS10668 Rev 6
- - - 2628284141 PB5 I/O FT -
SPI1_MOSI,
LPTIM1_IN1,
I2C1_SMBA,
TIM22_CH2
COMP2_INP
- A3252729294242 PB6 I/OFTf -
USART2_TX,
I2C1_SCL,
LPTIM1_ETR,
TIM21_CH1
COMP2_INP
- A4262830304343 PB7 I/OFTf -
USART2_RX,
I2C1_SDA,
LPTIM1_IN2
COMP2_INP,
VREF_PVD_IN
1 A5 27 1 31 31 44 44 BOOT0 I - - - -
- - - - - 32 45 45 PB8 I/O FTf - I2C1_SCL -
- - - - - - 46 46 PB9 I/O FTf - EVENTOUT,
I2C1_SDA -
- - 28 - 32 - 47 47 VSS S - - - -
- - 1 - 1 1 48 48 VDD S - - - -
1. VSS pins are connected to the exposed pad (see Figure 43: UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch
quad flat package outline).
Table 15. Pin definitions (continued)
Pin Number
Pin name
(function
after reset)
Pin
type
I/O structure
Note
Alternate
functions Additional functions
TSSOP20
WLCSP25
UFQFPN28
UFQFPN28 (STM32L031GxUxS only)
LQFP32
UFQFPN32(1)
LQFP48
UFQFPN48
STM32L031x4/6 Pin descriptions
DS10668 Rev 6 45/126
Table 16. Alternate functions
Ports
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7
SPI1/USART2
/LPTIM/TIM21
/EVENTOUT/
SYS_AF
SPI1/I2C1/
LPTIM
LPTIM/TIM2/
EVENTOUT/
SYS_AF
I2C1/
EVENTOUT
I2C1/USART2/
LPUART1/
TIM22/
EVENTOUT
TIM2/21/22 LPUART1/
EVENTOUT COMP1/2
Port A
PA0 - LPTIM1_IN1 TIM2_CH1 - USART2_CTS TIM2_ETR - COMP1_OUT
PA1 EVENTOUT LPTIM1_IN2 TIM2_CH2 I2C1_SMBA USART2_RTS/
USART2_DE TIM21_ETR - -
PA2 TIM21_CH1 - TIM2_CH3 - USART2_TX - LPUART1_TX COMP2_OUT
PA3 TIM21_CH2 - TIM2_CH4 - USART2_RX - LPUART1_RX
PA4 SPI1_NSS LPTIM1_IN1 - - USART2_CK TIM22_ETR - -
PA5 SPI1_SCK LPTIM1_IN2 TIM2_ETR - - TIM2_CH1 - -
PA6 SPI1_MISO LPTIM1_ETR - - LPUART1_CTS TIM22_CH1 EVENTOUT COMP1_OUT
PA7 SPI1_MOSI LPTIM1_OUT - - USART2_CTS TIM22_CH2 EVENTOUT COMP2_OUT
PA8 MCO - LPTIM1_IN1 EVENTOUT USART2_CK TIM2_CH1 - -
PA9 MCO I2C1_SCL - - USART2_TX TIM22_CH1 - -
PA10 - I2C1_SDA - - USART2_RX TIM22_CH2 - -
PA11 SPI1_MISO - EVENTOUT - USART2_CTS TIM21_CH2 - COMP1_OUT
PA12 SPI1_MOSI - EVENTOUT - USART2_RTS/
USART2_DE --COMP2_OUT
PA13 SWDIO LPTIM1_ETR - - - - LPUART1_RX -
PA14 SWCLK LPTIM1_OUT - I2C1_SMBA USART2_TX - LPUART1_TX -
PA15 SPI1_NSS - TIM2_ETR EVENTOUT USART2_RX TIM2_CH1 - -
Pin descriptions STM32L031x4/6
46/126 DS10668 Rev 6
Port B
PB0 EVENTOUT SPI1_MISO - - USART2_RTS/
USART2_DE TIM2_CH3 - -
PB1 USART2_CK SPI1_MOSI - - LPUART1_RTS
/LPUART1_DE TIM2_CH4 - -
PB2 - - LPTIM1_OUT - - - - -
PB3 SPI1_SCK - TIM2_CH2 - EVENTOUT - - -
PB4 SPI1_MISO - EVENTOUT - TIM22_CH1 - - -
PB5 SPI1_MOSI - LPTIM1_IN1 I2C1_SMBA TIM22_CH2 - - -
PB6 USART2_TX I2C1_SCL LPTIM1_ETR - - TIM21_CH1 - -
PB7 USART2_RX I2C1_SDA LPTIM1_IN2 - - - - -
PB8 - - - - I2C1_SCL - - -
PB9 - - EVENTOUT - I2C1_SDA - - -
PB10 - - TIM2_CH3 - - - LPUART1_TX -
PB11 EVENTOUT - TIM2_CH4 - - - LPUART1_RX -
PB12 SPI1_NSS - - - - - EVENTOUT -
PB13 SPI1_SCK - MCO - - TIM21_CH1 LPUART1_CTS -
PB14 SPI1_MISO - RTC_OUT - - TIM21_CH2 LPUART1_RTS
/LPUART1_DE -
PB15 SPI1_MOSI - RTC_REFIN - - - - -
Port C PC0 LPTIM1_IN1 - EVENTOUT - - - LPUART1_RX -
Port H
PH0------- -
PH1------- -
Table 16. Alternate functions (continued)
Ports
AF0 AF1 AF2 AF3 AF4 AF5 AF6 AF7
SPI1/USART2
/LPTIM/TIM21
/EVENTOUT/
SYS_AF
SPI1/I2C1/
LPTIM
LPTIM/TIM2/
EVENTOUT/
SYS_AF
I2C1/
EVENTOUT
I2C1/USART2/
LPUART1/
TIM22/
EVENTOUT
TIM2/21/22 LPUART1/
EVENTOUT COMP1/2
DS10668 Rev 6 47/126
STM32L031x4/6 Memory mapping
47
5 Memory mapping
Refer to the product line reference manual for details on the memory mapping as well as the
boundary addresses for all peripherals.
Figure 11. Pin loading conditions Figure 12. Pin input voltage
Electrical characteristics STM32L031x4/6
48/126 DS10668 Rev 6
6 Electrical characteristics
6.1 Parameter conditions
Unless otherwise specified, all voltages are referenced to VSS.
6.1.1 Minimum and maximum values
Unless otherwise specified the minimum and maximum values are guaranteed in the worst
conditions of ambient temperature, supply voltage and frequencies by tests in production on
100% of the devices with an ambient temperature at TA = 25 °C and TA = TAmax (given by
the selected temperature range).
Data based on characterization results, design simulation and/or technology characteristics
are indicated in the table footnotes and are not tested in production. Based on
characterization, the minimum and maximum values refer to sample tests and represent the
mean value plus or minus three times the standard deviation (mean±3σ).
6.1.2 Typical values
Unless otherwise specified, typical data are based on TA = 25 °C, VDD = 3.6 V (for the
1.65 V VDD 3.6 V voltage range). They are given only as design guidelines and are
not tested.
Typical ADC accuracy values are determined by characterization of a batch of samples from
a standard diffusion lot over the full temperature range, where 95% of the devices have an
error less than or equal to the value indicated (mean±2σ).
6.1.3 Typical curves
Unless otherwise specified, all typical curves are given only as design guidelines and are
not tested.
6.1.4 Loading capacitor
The loading conditions used for pin parameter measurement are shown in Figure 11.
6.1.5 Pin input voltage
The input voltage measurement on a pin of the device is described in Figure 12.
Figure 11. Pin loading conditions Figure 12. Pin input voltage
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DS10668 Rev 6 49/126
STM32L031x4/6 Electrical characteristics
96
6.1.6 Power supply scheme
Figure 13. Power supply scheme
6.1.7 Current consumption measurement
Figure 14. Current consumption measurement scheme
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Electrical characteristics STM32L031x4/6
50/126 DS10668 Rev 6
6.2 Absolute maximum ratings
Stresses above the absolute maximum ratings listed in Table 17: Voltage characteristics,
Table 18: Current characteristics, and Table 19: Thermal characteristics may cause
permanent damage to the device. These are stress ratings only and functional operation of
the device at these conditions is not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability. Device mission profile (application conditions)
is compliant with JEDEC JESD47 Qualification Standard. Extended mission profiles are
available on demand.
Table 17. Voltage characteristics
Symbol Ratings Min Max Unit
VDD–VSS
External main supply voltage
(including VDDA, VDD)(1)
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power
supply, in the permitted range.
–0.3 4.0
V
VIN(2)
2. VIN maximum must always be respected. Refer to Table 18 for maximum allowed injected current values.
Input voltage on FT and FTf pins VSS 0.3 VDD+4.0
Input voltage on TC pins VSS 0.3 4.0
Input voltage on BOOT0 VSS VDD + 4.0
Input voltage on any other pin VSS 0.3 4.0
|ΔVDD| Variations between different VDDx power pins - 50
mV|VDDA-VDDx|Variations between any VDDx and VDDA power
pins(3)
3. It is recommended to power VDD and VDDA from the same source. A maximum difference of 300 mV
between VDD and VDDA can be tolerated during power-up and device operation.
- 300
|ΔVSS| Variations between all different ground pins - 50
VESD(HBM)
Electrostatic discharge voltage
(human body model) see Section 6.3.11
(sourceW)
DS10668 Rev 6 51/126
STM32L031x4/6 Electrical characteristics
96
Table 18. Current characteristics
Symbol Ratings Max. Unit
ΣIVDD(2) Total current into sum of all VDD power lines (source)(1)
1. All main power (VDD, VDDA) and ground (VSS, VSSA) pins must always be connected to the external power
supply, in the permitted range.
105
mA
ΣIVSS(2)
2. This current consumption must be correctly distributed over all I/Os and control pins. The total output
current must not be sunk/sourced between two consecutive power supply pins referring to high pin count
LQFP packages.
Total current out of sum of all VSS ground lines (sink)(1) 105
IVDD(PIN) Maximum current into each VDD power pin (source)(1) 100
IVSS(PIN) Maximum current out of each VSS ground pin (sink)(1) 100
IIO
Output current sunk by any I/O and control pin except FTf
pins 16
Output current sunk by FTf pins 22
Output current sourced by any I/O and control pin –16
ΣIIO(PIN)(3)
3. These values apply only to STM32L031GxUxS part number.
Total output current sunk by sum of all IOs and control
pins(4)
4. This current consumption must be correctly distributed over all I/Os and control pins. In particular, it must
be located the closest possible to the couple of supply and ground, and distributed on both sides.
45
Total output current sourced by sum of all IOs and control
pins(4) -45
ΣIIO(PIN)(5)
5. These values apply to all part numbers except for STM32L031GxUxS.
Total output current sunk by sum of all IOs and control
pins(2) 90
Total output current sourced by sum of all IOs and control
pins(2) -90
IINJ(PIN)
Injected current on FT, FFf, RST and B pins –5/+0(6)
6. Positive current injection is not possible on these I/Os. A negative injection is induced by VIN<VSS. IINJ(PIN)
must never be exceeded. Refer to Ta ble 17 for maximum allowed input voltage values.
Injected current on TC pin ± 5(7)
7. A positive injection is induced by VIN > VDD while a negative injection is induced by VIN < VSS. IINJ(PIN)
must never be exceeded. Refer to Table 17: Voltage characteristics for the maximum allowed input voltage
values.
ΣIINJ(PIN) Total injected current (sum of all I/O and control pins)(8)
8. When several inputs are submitted to a current injection, the maximum ΣIINJ(PIN) is the absolute sum of the
positive and negative injected currents (instantaneous values).
± 25
Table 19. Thermal characteristics
Symbol Ratings Value Unit
TSTG Storage temperature range –65 to +150 °C
TJMaximum junction temperature 150 °C
Electrical characteristics STM32L031x4/6
52/126 DS10668 Rev 6
6.3 Operating conditions
6.3.1 General operating conditions
Table 20. General operating conditions
Symbol Parameter Conditions Min Max Unit
fHCLK Internal AHB clock frequency - 0 32
MHzfPCLK1 Internal APB1 clock frequency - 0 32
fPCLK2 Internal APB2 clock frequency - 0 32
VDD Standard operating voltage
BOR detector disabled 1.65 3.6
V
BOR detector enabled,
at power on 1.8 3.6
BOR detector disabled,
after power on 1.65 3.6
VDDA
Analog operating voltage
(all features)
Must be the same voltage
as VDD(1) 1.65 3.6 V
VIN
Input voltage on FT, FTf and RST pins(2) 2.0 V VDD 3.6 V –0.3 5.5
V
1.65 V VDD 2.0 V –0.3 5.2
Input voltage on BOOT0 pin - 0 5.5
Input voltage on TC pin - –0.3 VDD+0.3
PD
Power dissipation at TA = 85 °C (range 6)
or TA =105 °C (rage 7) (3)
LQFP48 package - 351
mW
UFQFPN48 package - 625
LQFP32 package - 333
UFQFPN32 package - 513
UFQFPN28 package - 167
WLCSP25 package - 286
TSSOP20 package - 333
Power dissipation at TA = 125 °C (range
3) (3)
LQFP48 package - 88
UFQFPN48 package - 156
LQFP32 package - 83
UFQFPN32 package - 128
UFQFPN28 package - 42
WLCSP25 package - 71
TSSOP20 package - 83
DS10668 Rev 6 53/126
STM32L031x4/6 Electrical characteristics
96
6.3.2 Embedded reset and power control block characteristics
The parameters given in the following table are derived from the tests performed under the
ambient temperature condition summarized in Table 20.
TA Temperature range
Maximum power
dissipation (range 6) –40 85
°C
Maximum power
dissipation (range 7) –40 105
Maximum power
dissipation (range 3) –40 125
TJ
Junction temperature range (range 6) -40 °C TA85 °C –40 105
Junction temperature range (range 7) -40 °C TA 105 °C –40 125
Junction temperature range (range 3) -40 °C TA 125 °C –40 130
1. It is recommended to power VDD and VDDA from the same source. A maximum difference of 300 mV between VDD and
VDDA can be tolerated during power-up and normal operation.
2. To sustain a voltage higher than VDD+0.3V, the internal pull-up/pull-down resistors must be disabled.
3. If TA is lower, higher PD values are allowed as long as TJ does not exceed TJ max (see Table 19: Thermal characteristics
on page 51).
Table 20. General operating conditions (continued)
Symbol Parameter Conditions Min Max Unit
Table 21. Embedded reset and power control block characteristics
Symbol Parameter Conditions Min Typ Max Unit
tVDD(1)
VDD rise time rate
BOR detector enabled 0 -
µs/V
BOR detector disabled 0 - 1000
VDD fall time rate
BOR detector enabled 20 -
BOR detector disabled 0 - 1000
TRSTTEMPO(1) Reset temporization
VDD rising, BOR enabled - 2 3.3
ms
VDD rising, BOR disabled(2) 0.4 0.7 1.6
VPOR/PDR
Power on/power down reset
threshold
Falling edge 1 1.5 1.65
V
Rising edge 1.3 1.5 1.65
VBOR0 Brown-out reset threshold 0
Falling edge 1.67 1.7 1.74
Rising edge 1.69 1.76 1.8
VBOR1 Brown-out reset threshold 1
Falling edge 1.87 1.93 1.97
Rising edge 1.96 2.03 2.07
VBOR2 Brown-out reset threshold 2
Falling edge 2.22 2.30 2.35
Rising edge 2.31 2.41 2.44
Electrical characteristics STM32L031x4/6
54/126 DS10668 Rev 6
VBOR3 Brown-out reset threshold 3
Falling edge 2.45 2.55 2.6
V
Rising edge 2.54 2.66 2.7
VBOR4 Brown-out reset threshold 4
Falling edge 2.68 2.8 2.85
Rising edge 2.78 2.9 2.95
VPVD0
Programmable voltage detector
threshold 0
Falling edge 1.8 1.85 1.88
Rising edge 1.88 1.94 1.99
VPVD1 PVD threshold 1
Falling edge 1.98 2.04 2.09
Rising edge 2.08 2.14 2.18
VPVD2 PVD threshold 2
Falling edge 2.20 2.24 2.28
Rising edge 2.28 2.34 2.38
VPVD3 PVD threshold 3
Falling edge 2.39 2.44 2.48
Rising edge 2.47 2.54 2.58
VPVD4 PVD threshold 4
Falling edge 2.57 2.64 2.69
Rising edge 2.68 2.74 2.79
VPVD5 PVD threshold 5
Falling edge 2.77 2.83 2.88
Rising edge 2.87 2.94 2.99
VPVD6 PVD threshold 6
Falling edge 2.97 3.05 3.09
Rising edge 3.08 3.15 3.20
Vhyst Hysteresis voltage
BOR0 threshold - 40 -
mV
All BOR and PVD thresholds
excepting BOR0 -100-
1. Guaranteed by characterization results.
2. Valid for device version without BOR at power up. Please see option "D" in Ordering information scheme for more details.
Table 21. Embedded reset and power control block characteristics (continued)
Symbol Parameter Conditions Min Typ Max Unit
(2)
DS10668 Rev 6 55/126
STM32L031x4/6 Electrical characteristics
96
6.3.3 Embedded internal reference voltage
The parameters given in Table 23 are based on characterization results, unless otherwise
specified.
Table 22. Embedded internal reference voltage calibration values
Calibration value name Description Memory address
VREFINT_CAL Raw data acquired at temperature
of 25 °C, VDDA= 3 V 0x1FF8 0078 - 0x1FF8 0079
Table 23. Embedded internal reference voltage(1)
Symbol Parameter Conditions Min Typ Max Unit
VREFINT out(2) Internal reference voltage – 40 °C < TJ < +125 °C 1.202 1.224 1.242 V
TVREFINT Internal reference startup time - - 2 3 ms
VVREF_MEAS
VDDA voltage during VREFINT
factory measure -2.9933.01V
AVREF_MEAS
Accuracy of factory-measured
VREFINT value(3)
Including uncertainties
due to ADC and VDDA
values
-- ±5mV
TCoeff(4) Temperature coefficient –40 °C < TJ < +125 °C - 25 100 ppm/°C
ACoeff(4) Long-term stability 1000 hours, T = 25 °C - - 1000 ppm
VDDCoeff(4) Voltage coefficient 3.0 V < VDDA < 3.6 V - - 2000 ppm/V
TS_vrefint(4)(5)
ADC sampling time when
reading the internal reference
voltage
-510-µs
TADC_BUF(4) Startup time of reference
voltage buffer for ADC ---10µs
IBUF_ADC(4) Consumption of reference
voltage buffer for ADC - - 13.5 25 µA
IVREF_OUT(4) VREF_OUT output current(6) ---1µA
CVREF_OUT(4) VREF_OUT output load - - - 50 pF
ILPBUF(4)
Consumption of reference
voltage buffer for VREF_OUT
and COMP
- - 730 1200 nA
VREFINT_DIV1(4) 1/4 reference voltage - 24 25 26
%
VREFINT
VREFINT_DIV2(4) 1/2 reference voltage - 49 50 51
VREFINT_DIV3(4) 3/4 reference voltage - 74 75 76
1. Refer to Table 35: Peripheral current consumption in Stop and Standby mode for the value of the internal reference current
consumption (IREFINT).
2. Guaranteed by test in production.
3. The internal VREF value is individually measured in production and stored in dedicated EEPROM bytes.
4. Guaranteed by design.
5. Shortest sampling time can be determined in the application by multiple iterations.
6. To guarantee less than 1% VREF_OUT deviation.
Electrical characteristics STM32L031x4/6
56/126 DS10668 Rev 6
6.3.4 Supply current characteristics
The current consumption is a function of several parameters and factors such as the
operating voltage, temperature, I/O pin loading, device software configuration, operating
frequencies, I/O pin switching rate, program location in memory and executed binary code.
The current consumption is measured as described in Figure 14: Current consumption
measurement scheme.
All Run-mode current consumption measurements given in this section are performed with a
reduced code that gives a consumption equivalent to Dhrystone 2.1 code if not specified
otherwise.
The current consumption values are derived from the tests performed under ambient
temperature and VDD supply voltage conditions summarized in Table 20: General operating
conditions unless otherwise specified.
The MCU is placed under the following conditions:
All I/O pins are configured in analog input mode
All peripherals are disabled except when explicitly mentioned
The Flash memory access time and prefetch is adjusted depending on fHCLK
frequency and voltage range to provide the best CPU performance unless otherwise
specified.
When the peripherals are enabled fAPB1 = fAPB2 = fAPB
When PLL is on, the PLL inputs are equal to HSI = 16 MHz (if internal clock is used) or
HSE = 16 MHz (if HSE bypass mode is used)
The HSE user clock is applied to OSCI_IN input (LQFP48 package) and to CK_IN
(other packages). It follows the characteristic specified in Table 37: High-speed
external user clock characteristics
For maximum current consumption VDD = VDDA = 3.6 V is applied to all supply pins
For typical current consumption VDD = VDDA = 3.0 V is applied to all supply pins if not
specified otherwise
The parameters given in Table 44, Table 20 and Table 21 are derived from tests performed
under ambient temperature and VDD supply voltage conditions summarized in Tabl e 20.
DS10668 Rev 6 57/126
STM32L031x4/6 Electrical characteristics
96
Table 24. Current consumption in Run mode, code with data processing running
from Flash memory
Symbol Parameter Conditions fHCLK Typ Max(1) Unit
IDD
(Run
from
Flash)
Supply
current in
Run mode,
code
executed
from Flash
fHSE = fHCLK up to
16 MHz included,
fHSE = fHCLK/2 above
16 MHz (PLL on)(2)
Range 3, VCORE = 1.2 V
VOS[1:0] = 11
1 MHz 140 200
µA2 MHz 245 310
4MHz 460 540
Range 2, VCORE = 1.5 V,
VOS[1:0] = 10,
4 MHz 0.56 0.63
mA
8 MHz 1.1 1.2
16 MHz 2.1 2.3
Range 1, VCORE = 1.8 V,
VOS[1:0] = 01
8 MHz 1.25 1.4
16 MHz 2.5 2.7
32 MHz 5 5.6
HSI clock
Range 2, VCORE = 1.5 V,
VOS[1:0] = 10, 16 MHz 2.1 2.4
Range 1, VCORE = 1.8 V,
VOS[1:0] = 01 32 MHz 5.1 5.7
MSI clock Range 3, VCORE = 1.2 V,
VOS[1:0] = 11
65 kHz 34.5 110
µA524 kHz 86 150
4.2 MHz 505 570
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).
Table 25. Current consumption in Run mode vs code type,
code with data processing running from Flash memory
Symbol Parameter Conditions fHCLK Typ Unit
IDD
(Run
from
Flash)
Supply
current in
Run mode,
code
executed
from Flash
memory
fHSE = fHCLK up to
16 MHz included,
fHSE = fHCLK/2 above
16 MHz (PLL ON)(1)
Range 3,
VCORE=1.2 V,
VOS[1:0] = 11
Dhrystone
4 MHz
460
µA
CoreMark 455
Fibonacci 330
while(1) 305
while(1), prefetch
OFF 320
Range 1,
VOS[1:0] = 01,
VCORE = 1.8 V
Dhrystone
32 MHz
5
mA
CoreMark 5.15
Fibonacci 5
while(1) 4.35
while(1), prefetch
OFF 3.85
1. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).
II: III
Electrical characteristics STM32L031x4/6
58/126 DS10668 Rev 6
Figure 15. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from
Flash memory, Range 2, HSE = 16 MHz, 1WS
Figure 16. IDD vs VDD, at TA= 25/55/85/105 °C, Run mode, code running from
Flash memory, Range 2, HSI16, 1WS
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DS10668 Rev 6 59/126
STM32L031x4/6 Electrical characteristics
96
Table 26. Current consumption in Run mode, code with data processing running from RAM
Symbol Parameter Conditions fHCLK Typ Max(1) Unit
IDD (Run
from
RAM)
Supply current in
Run mode, code
executed from
RAM, Flash
switched OFF
fHSE = fHCLK up to 16
MHz, included
fHSE = fHCLK/2 above
16 MHz
(PLL ON)(2)
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
1 MHz 115 170
µA2 MHz 210 250
4 MHz 385 420
Range 2,
VCORE = 1.5 ,V,
VOS[1:0] = 10
4 MHz 0.48 0.6
mA
8 MHz 0.935 1.1
16 MHz 1.8 2
Range 1,
VCORE =1.8V,
VOS[1:0] = 01
8 MHz 1.1 1.3
16 MHz 2.1 2.3
32 MHz 4.5 4.7
MSI clock
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
65 kHz 22 52
µA524 kHz 70.5 91
4.2 MHz 420 450
HSI16 clock source
(16 MHz)
Range 2,
VCORE =1.5V,
VOS[1:0] = 10
16 MHz 1.95 2.2
mA
Range 1,
VCORE =1.8V,
VOS[1:0] = 01
32 MHz 4.7 5.1
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).
Table 27. Current consumption in Run mode vs code type,
code with data processing running from RAM(1)
Symbol Parameter Conditions fHCLK Typ Unit
IDD (Run
from
RAM)
Supply current in
Run mode, code
executed from
RAM, Flash
switched OFF
fHSE = fHCLK up to 16
MHz, included,
fHSE = fHCLK/2 above
16 MHz (PLL ON)(2)
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
Dhrystone
4 MHz
385
µA
CoreMark 395
Fibonacci 360
while(1) 265
Range 1,
VCORE =1.8V,
VOS[1:0] = 01
Dhrystone
32 MHz
4.5
mA
CoreMark 4.65
Fibonacci 4.2
while(1) 3.05
1. Guaranteed by characterization results, unless otherwise specified.
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).
Electrical characteristics STM32L031x4/6
60/126 DS10668 Rev 6
Table 28. Current consumption in Sleep mode
Symbol Parameter Conditions fHCLK Typ Max(1) Unit
IDD (Sleep)
Supply current
in Sleep
mode, Flash
memory OFF
fHSE = fHCLK up to
16 MHz included,
fHSE = fHCLK/2
above 16 MHz (PLL
ON)(2)
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
1 MHz 36.5 87
µA
2 MHz 58 100
4 MHz 100 170
Range 2,
VCORE = 1.5 V,
VOS[1:0] = 10
4 MHz 125 190
8 MHz 230 310
16 MHz 450 540
Range 1,
VCORE = 1.8 V,
VOS[1:0] = 01
8 MHz 275 360
16 MHz 555 650
32 MHz 1350 1600
HSI16 clock source
(16 MHz)
Range 2,
VCORE = 1.5 V,
VOS[1:0] = 10
16 MHz 585 690
Range 1,
VCORE = 1.8 V,
VOS[1:0] = 01
32 MHz 1500 1700
MSI clock
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
65 kHz 17 43
524 kHz 28 55
4.2 MHz 115 190
Supply current
in Sleep
mode, Flash
memory ON
fHSE = fHCLK up to
16 MHz included,
fHSE = fHCLK/2
above 16 MHz (PLL
ON)(2)
Range 3,
VCORE =1.2 V,
VOS[1:0] = 11
1 MHz 49 160
2 MHz 69 190
4 MHz 115 230
Range 2,
VCORE =1.5V,
VOS[1:0] = 10
4 MHz 135 200
8 MHz 240 320
16 MHz 460 550
Range 1,
VCORE = 1.8 V,
VOS[1:0]=01
8 MHz 290 370
16 MHz 565 670
32 MHz 1350 1600
HSI16 clock source
(16 MHz)
Range 2,
VCORE = 1.5 V,
VOS[1:0]=10
16 MHz 600 700
Range 1,
VCORE = 1.8 V,
VOS[1:0] = 01
32 MHz 1500 1700
MSI clock
Range 3,
VCORE =1.2V,
VOS[1:0] = 11
65 kHz 28 55
524 kHz 39.5 67
4.2 MHz 125 200
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
2. Oscillator bypassed (HSEBYP = 1 in RCC_CR register).
DS10668 Rev 6 61/126
STM32L031x4/6 Electrical characteristics
96
Table 29. Current consumption in Low-power run mode
Symbol Parameter Conditions Typ Max(1) Unit
IDD
(LP Run)
Supply
current in
Low-power
run mode
All
peripherals
off, code
executed
from RAM,
Flash
memory
OFF, VDD
from 1.65 V
to 3.6 V
MSI clock, 65 kHz
fHCLK = 32 kHz
TA = -40 °C to 25 °C 6.3 8.4
µA
TA = 85 °C 9.15 13
TA = 105 °C 12.5 19
TA = 125 °C 20.5 36
MSI clock, 65 kHz
fHCLK = 65 kHz
TA =-40 °C to 25 °C 9.45 12
TA = 85 °C 12.5 15
TA = 105 °C 16 22
TA = 125 °C 24 38
MSI clock, 131 kHz
fHCLK = 131 kHz
TA = -40 °C to 25 °C 17 20
TA = 55 °C 19 21
TA = 85 °C 20.5 24
TA = 105 °C 23.5 28
TA = 125 °C 31.5 46
All
peripherals
off, code
executed
from Flash
memory,
VDD from
1.65 V to
3.6 V
MSI clock, 65 kHz
fHCLK = 32 kHz
TA = -40 °C to 25 °C 18.5 23
TA = 85 °C 23 27
TA = 105 °C 27 33
TA = 125 °C 36 52
MSI clock, 65 kHz
fHCLK = 65 kHz
TA = -40 °C to 25 °C 22.5 26
TA = 85 °C 27.5 31
TA = 105 °C 31 38
TA = 125 °C 40.5 56
MSI clock, 131 kHz
fHCLK = 131 kHz
TA = -40 °C to 25 °C 32 36
TA = 55 °C 35 37
TA = 85 °C 37.5 42
TA = 105 °C 41 47
TA = 125 °C 50 65
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
HHH
Electrical characteristics STM32L031x4/6
62/126 DS10668 Rev 6
Figure 17. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Low-power run mode, code running
from RAM, Range 3, MSI (Range 0) at 64 KHz, 0 WS
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Table 30. Current consumption in Low-power sleep mode
Symbol Parameter Conditions Typ Max(1) Unit
IDD
(LP Sleep)
Supply
current in
Low-power
sleep mode
All peripherals
off, VDD from
1.65 V to 3.6 V
MSI clock, 65 kHz
fHCLK = 32 kHz
Flash memory OFF
TA = -40 °C to 25 °C 3.2(2) -
µA
MSI clock, 65 kHz
fHCLK = 32 kHz
Flash memory ON
TA = -40 °C to 25 °C 13 19
TA = 85 °C 16 21
TA = 105 °C 18.5 24
TA = 125 °C 23.5 32
MSI clock, 65 kHz
fHCLK = 65 kHz,
Flash memory ON
TA = -40 °C to 25 °C 13.5 19
TA = 85 °C 16.5 21
TA = 105 °C 18.5 24
TA = 125 °C 24 33
MSI clock, 131 kHz
fHCLK = 131 kHz,
Flash memory ON
TA = -40 °C to 25 °C 15.5 21
TA = 55 °C 17.5 22
TA = 85 °C 18.5 23
TA = 105 °C 21 26
TA = 125 °C 26 35
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
2. As the CPU is in Sleep mode, the difference between the current consumption with Flash memory ON and OFF (nearly
12 µA) is the same whatever the clock frequency.
2:: II:
DS10668 Rev 6 63/126
STM32L031x4/6 Electrical characteristics
96
Figure 18. IDD vs VDD, at TA= 25/55/ 85/105/125 °C, Stop mode with RTC enabled
and running on LSE Low drive
Figure 19. IDD vs VDD, at TA= 25/55/85/105/125 °C, Stop mode with RTC disabled,
all clocks off
Table 31. Typical and maximum current consumptions in Stop mode
Symbol Parameter Conditions Typ Max(1)
1. Guaranteed by characterization results at 125 °C, unless otherwise specified.
Unit
IDD (Stop) Supply current in Stop mode
TA = -40°C to 25°C 0.38 0.99
µA
TA = 55°C 0.54 1.9
TA= 85°C 1.35 4.2
TA = 105°C 3.1 9
TA = 125°C 7.55 19
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Electrical characteristics STM32L031x4/6
64/126 DS10668 Rev 6
Table 32. Typical and maximum current consumptions in Standby mode
Symbol Parameter Conditions Typ Max(1) Unit
IDD
(Standby)
Supply current in Standby
mode
Independent watchdog
and LSI enabled
TA = -40 °C to 25 °C 0.8 1.6
µA
TA = 55 °C 0.9 1.8
TA= 85 °C 1 2
TA = 105 °C 1.3 3
TA = 125 °C 2.15 7
Independent watchdog
and LSI off
TA = -40 °C to 25 °C 0.255 0.6
TA = 55 °C 0.28 0.7
TA = 85 °C 0.405 1
TA = 105 °C 0.7 1.7
TA = 125 °C 1.55 5
1. Guaranteed by characterization results at 125 °C, unless otherwise specified
Table 33. Average current consumption during wakeup
Symbol parameter System frequency
Current
consumption
during wakeup
Unit
IDD (WU from
Stop)
Supply current during wakeup from
Stop mode
HSI 1
mA
HSI/4 0.7
MSI 4,2 MHz 0.7
MSI 1,05 MHz 0.4
MSI 65 KHz 0.1
IDD (Reset) Reset pin pulled down - 0.21
IDD (Power Up) BOR on - 0.23
IDD (WU from
StandBy)
With Fast wakeup set MSI 2,1 MHz 0.5
With Fast wakeup disabled MSI 2,1 MHz 0.12
DS10668 Rev 6 65/126
STM32L031x4/6 Electrical characteristics
96
On-chip peripheral current consumption
The current consumption of the on-chip peripherals is given in the following tables. The
MCU is placed under the following conditions:
all I/O pins are in input mode with a static value at VDD or VSS (no load)
all peripherals are disabled unless otherwise mentioned
the given value is calculated by measuring the current consumption
with all peripherals clocked off
with only one peripheral clocked on
Table 34. Peripheral current consumption in Run or Sleep mode(1)
Peripheral
Typical consumption, VDD = 3.0 V, TA = 25 °C
Unit
Range 1,
VCORE=1.8 V
VOS[1:0] = 01
Range 2,
VCORE=1.5 V
VOS[1:0] = 10
Range 3,
VCORE=1.2 V
VOS[1:0] = 11
Low-power
sleep and run
APB1
WWDG3222
µA/MHz (fHCLK)
LPUART1 8 6.5 5.5 6
I2C1 11 9.5 7.5 9
LPTIM1 10 8.5 6.5 8
TIM2 10.5 8.5 7 9
USART2 14.5 12 9.5 11
APB2
ADC1(2) 5.553.54
µA/MHz (fHCLK)
SPI1 4 3 3 2.5
TIM21 7.5 6 5 5.5
TIM227656
DBGMCU 1.5 1 1 0.5
SYSCFG 2.5 2 2 1.5
Cortex-
M0+ core
I/O port
GPIOA 3.5 3 2.5 2.5
µA/MHz (fHCLK)
GPIOB 3.5 2.5 2 2.5
GPIOC 8.5 6.5 5.5 7
GPIOH 1.5 1 1 0.5
AHB
CRC 1.5 1 1 1
µA/MHz (fHCLK)
FLASH 0(3) 0(3) 0(3) 0(3)
DMA1 10 8 6.5 8.5
All enabled 101 83 66 85
PWR 2.5 2 2 1 µA/MHz (fHCLK)
1. Data based on differential IDD measurement between all peripherals off an one peripheral with clock enabled, in the following
conditions: fHCLK = 32 MHz (range 1), fHCLK = 16 MHz (range 2), fHCLK = 4 MHz (range 3), fHCLK = 64kHz (Low-power
run/sleep), fAPB1 = fHCLK, fAPB2 = fHCLK, default prescaler value for each peripheral. The CPU is in Sleep mode in both cases.
No I/O pins toggling. Not tested in production.
2. HSI oscillator is off for this measure.
3. Current consumption is negligible and close to 0 µA.
Electrical characteristics STM32L031x4/6
66/126 DS10668 Rev 6
6.3.5 Wakeup time from low-power mode
The wakeup times given in the following table are measured with the MSI or HSI16 RC
oscillator. The clock source used to wake up the device depends on the current operating
mode:
Sleep mode: the clock source is the clock that was set before entering Sleep mode
Stop mode: the clock source is either the MSI oscillator in the range configured before
entering Stop mode, the HSI16 or HSI16/4.
Standby mode: the clock source is the MSI oscillator running at 2.1 MHz
All timings are derived from tests performed under ambient temperature and VDD supply
voltage conditions summarized in Table 20.
Table 35. Peripheral current consumption in Stop and Standby mode(1)
Symbol Peripheral
Typical consumption, TA = 25 °C
Unit
VDD=1.8 V VDD=3.0 V
IDD(PVD / BOR) -0.71.2
µA
IREFINT -1.31.4
- LSE Low drive(2) 0.1 0.1
- LSI 0.27 0.31
-IWDG0.2 0.3
- LPTIM1, Input 100 Hz 0.01 0.01
- LPTIM1, Input 1 MHz 6 6
- LPUART1 0.2 0.2
-RTC (LSE in Bypass
mode) 0.2 0.2
1. LPTIM, LPUART peripherals can operate in Stop mode but not in Standby mode
2. LSE Low drive consumption is the difference between an external clock on OSC32_IN and a quartz between OSC32_IN
and OSC32_OUT.
DS10668 Rev 6 67/126
STM32L031x4/6 Electrical characteristics
96
Table 36. Low-power mode wakeup timings
Symbol Parameter Conditions Typ Max Unit
tWUSLEEP Wakeup from Sleep mode fHCLK = 32 MHz 7 8
Number
of clock
cycles
tWUSLEEP_
LP
Wakeup from Low-power sleep mode,
fHCLK = 262 kHz
fHCLK = 262 kHz
Flash memory enabled 78
fHCLK = 262 kHz
Flash memory switched OFF 910
tWUSTOP
Wakeup from Stop mode, regulator in Run
mode
fHCLK = fMSI = 4.2 MHz 5.0 8
µs
fHCLK = fHSI = 16 MHz 4.9 7
fHCLK = fHSI/4 = 4 MHz 8.0 11
Wakeup from Stop mode, regulator in low-
power mode
fHCLK = fMSI = 4.2 MHz
Voltage range 1 5.0 8
fHCLK = fMSI = 4.2 MHz
Voltage range 2 5.0 8
fHCLK = fMSI = 4.2 MHz
Voltage range 3 5.0 8
fHCLK = fMSI = 2.1 MHz 7.3 13
fHCLK = fMSI = 1.05 MHz 13 23
fHCLK = fMSI = 524 kHz 28 38
fHCLK = fMSI = 262 kHz 51 65
fHCLK = fMSI = 131 kHz 100 120
fHCLK = MSI = 65 kHz 200 260
fHCLK = fHSI = 16 MHz 4.9 7
fHCLK = fHSI/4 = 4 MHz 8.0 11
Wakeup from Stop mode, regulator in low-
power mode, code running from RAM
fHCLK = fHSI = 16 MHz 4.9 7
fHCLK = fHSI/4 = 4 MHz 7.9 10
fHCLK = fMSI = 4.2 MHz 4.7 8
tWUSTDBY
Wakeup from Standby mode
FWU bit = 1 fHCLK = MSI = 2.1 MHz 65 130
Wakeup from Standby mode
FWU bit = 0 fHCLK = MSI = 2.1 MHz 2.2 3 ms
Electrical characteristics STM32L031x4/6
68/126 DS10668 Rev 6
6.3.6 External clock source characteristics
High-speed external user clock generated from an external source
In bypass mode the HSE oscillator is switched off and the input pin is a standard GPIO.The
external clock signal has to respect the I/O characteristics in Section 6.3.12. However, the
recommended clock input waveform is shown in Figure 20.
Figure 20. High-speed external clock source AC timing diagram
Table 37. High-speed external user clock characteristics(1)
1. Guaranteed by design.
Symbol Parameter Conditions Min Typ Max Unit
fHSE_ext
User external clock source
frequency
CSS is on or PLL
is used 1832MHz
CSS is off, PLL
not used 0832MHz
VHSEH
OSC_IN/CK_IN(2) input pin high
level voltage
2. HSE external user clock is applied to OSC_IN on LQFP48 package and to CK_IN on other packages.
-
0.7VDD -V
DD
V
VHSEL
OSC_IN/CK_IN(2) input pin low
level voltage VSS -0.3V
DD
tw(HSE)
tw(HSE)
OSC_IN/CK_IN(2) high or low time 12 - -
ns
tr(HSE)
tf(HSE)
OSC_IN/CK_IN(2) rise or fall time - - 20
Cin(HSE) OSC_IN/CK_IN(2) input capacitance - 2.6 - pF
DuCy(HSE) Duty cycle 45 - 55 %
IL
OSC_IN/CK_IN(2) Input leakage
current VSS VIN VDD --±1µA
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STM32L031x4/6 Electrical characteristics
96
Low-speed external user clock generated from an external source
The characteristics given in the following table result from tests performed using a low-
speed external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 20.
Figure 21. Low-speed external clock source AC timing diagram
Table 38. Low-speed external user clock characteristics(1)
1. Guaranteed by design.
Symbol Parameter Conditions Min Typ Max Unit
fLSE_ext
User external clock source
frequency
-
1 32.768 1000 kHz
VLSEH
OSC32_IN input pin high level
voltage 0.7VDD -V
DD
V
VLSEL
OSC32_IN input pin low level
voltage VSS -0.3V
DD
tw(LSE)
tw(LSE)
OSC32_IN high or low time 465 - -
ns
tr(LSE)
tf(LSE)
OSC32_IN rise or fall time - - 10
CIN(LSE) OSC32_IN input capacitance - - 0.6 - pF
DuCy(LSE) Duty cycle - 45 - 55 %
ILOSC32_IN Input leakage current VSS VIN VDD --±1µA
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High-speed external clock generated from a crystal/ceramic resonator
The high-speed external (HSE) clock can be supplied with a 1 to 25 MHz crystal/ceramic
resonator oscillator (LQFP48 package only). All the information given in this paragraph are
based on characterization results obtained with typical external components specified in
Table 39. In the application, the resonator and the load capacitors have to be placed as
close as possible to the oscillator pins in order to minimize output distortion and startup
stabilization time. Refer to the crystal resonator manufacturer for more details on the
resonator characteristics (frequency, package, accuracy).
For CL1 and CL2, it is recommended to use high-quality external ceramic capacitors in the
5 pF to 25 pF range (typ.), designed for high-frequency applications, and selected to match
the requirements of the crystal or resonator (see Figure 22). CL1 and CL2 are usually the
same size. The crystal manufacturer typically specifies a load capacitance which is the
series combination of CL1 and CL2. PCB and MCU pin capacitance must be included (10 pF
can be used as a rough estimate of the combined pin and board capacitance) when sizing
CL1 and CL2. Refer to the application note AN2867 “Oscillator design guide for ST
microcontrollers” available from the ST website www.st.com.
Figure 22. HSE oscillator circuit diagram
Table 39. HSE oscillator characteristics(1)
1. Guaranteed by design.
Symbol Parameter Conditions Min Typ Max Unit
fOSC_IN Oscillator frequency - 1 25 MHz
RFFeedback resistor - - 200 - kΩ
Gm
Maximum critical crystal
transconductance Startup - - 700 µA
/V
tSU(HSE)
(2)
2. Guaranteed by characterization results. tSU(HSE) is the startup time measured from the moment it is
enabled (by software) to a stabilized 8 MHz oscillation is reached. This value is measured for a standard
crystal resonator and it can vary significantly with the crystal manufacturer.
Startup time VDD is stabilized - 2 - ms
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STM32L031x4/6 Electrical characteristics
96
Low-speed external clock generated from a crystal/ceramic resonator
The low-speed external (LSE) clock can be supplied with a 32.768 kHz crystal/ceramic
resonator oscillator. All the information given in this paragraph are based on
characterization results obtained with typical external components specified in Table 40. In
the application, the resonator and the load capacitors have to be placed as close as
possible to the oscillator pins in order to minimize output distortion and startup stabilization
time. Refer to the crystal resonator manufacturer for more details on the resonator
characteristics (frequency, package, accuracy).
Note: For information on selecting the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available from the ST website www.st.com.
Figure 23. Typical application with a 32.768 kHz crystal
Note: An external resistor is not required between OSC32_IN and OSC32_OUT and it is forbidden
to add one.
Table 40. LSE oscillator characteristics(1)
Symbol Parameter Conditions(2) Min(2) Typ Max Unit
fLSE LSE oscillator frequency - 32.768 - kHz
Gm
Maximum critical crystal
transconductance
LSEDRV[1:0]=00
lower driving capability --0.5
µA/V
LSEDRV[1:0]= 01
medium low driving capability - - 0.75
LSEDRV[1:0] = 10
medium high driving capability --1.7
LSEDRV[1:0]=11
higher driving capability --2.7
tSU(LSE)(3) Startup time VDD is stabilized - 2 - s
1. Guaranteed by design.
2. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator design guide for ST
microcontrollers”.
3. Guaranteed by characterization results. tSU(LSE) is the startup time measured from the moment it is enabled (by software) to
a stabilized 32.768 kHz oscillation is reached. This value is measured for a standard crystal resonator and it can vary
significantly with the crystal manufacturer. To increase speed, address a lower-drive quartz with a high- driver mode.
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6.3.7 Internal clock source characteristics
The parameters given in Table 41 are derived from tests performed under ambient
temperature and VDD supply voltage conditions summarized in Table 20.
High-speed internal 16 MHz (HSI16) RC oscillator
Table 41. 16 MHz HSI16 oscillator characteristics
Symbol Parameter Conditions Min Typ Max Unit
fHSI16 Frequency VDD = 3.0 V - 16 - MHz
TRIM(1)(2)
1. The trimming step differs depending on the trimming code. It is usually negative on the codes which are
multiples of 16 (0x00, 0x10, 0x20, 0x30...0xE0).
HSI16 user-
trimmed resolution
Trimming code is not a multiple of
16 -± 0.4 0.7 %
Trimming code is a multiple of 16 - - ± 1.5 %
ACCHSI16
(2)
2. Guaranteed by characterization results.
Accuracy of the
factory-calibrated
HSI16 oscillator
VDDA = 3.0 V, TA = 25 °C –1(3)
3. Guaranteed by test in production.
-1
(3) %
VDDA = 3.0 V, TA = 0 to 55 °C –1.5 - 1.5 %
VDDA = 3.0 V, TA = -10 to 70 °C –2 - 2 %
VDDA = 3.0 V, TA = -10 to 85 °C –2.5 - 2 %
VDDA = 3.0 V, TA = -10 to 105 °C –4 - 2 %
VDDA = 1.65 V to 3.6 V
TA = -40 to 125 °C –5.45 - 3.25 %
tSU(HSI16)(2) HSI16 oscillator
startup time - - 3.7 6 µs
IDD(HSI16)(2) HSI16 oscillator
power consumption - - 100 140 µA
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DS10668 Rev 6 73/126
STM32L031x4/6 Electrical characteristics
96
Figure 24. HSI16 minimum and maximum value versus temperature
Low-speed internal (LSI) RC oscillator
Multi-speed internal (MSI) RC oscillator
Table 42. LSI oscillator characteristics
Symbol Parameter Min Typ Max Unit
fLSI(1)
1. Guaranteed by test in production.
LSI frequency 26 38 56 kHz
DLSI(2)
2. This is a deviation for an individual part, once the initial frequency has been measured.
LSI oscillator frequency drift
0°C TA 85°C –10 - 4 %
tsu(LSI)(3)
3. Guaranteed by design.
LSI oscillator startup time - - 200 µs
IDD(LSI)(3) LSI oscillator power consumption - 400 510 nA
Table 43. MSI oscillator characteristics
Symbol Parameter Condition Typ Max Unit
fMSI
Frequency after factory calibration, done at
VDD= 3.3 V and TA = 25 °C
MSI range 0 65.5 -
kHz
MSI range 1 131 -
MSI range 2 262 -
MSI range 3 524 -
MSI range 4 1.05 -
MHzMSI range 5 2.1 -
MSI range 6 4.2 -
ACCMSI Frequency error after factory calibration - ±0.5 - %
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Electrical characteristics STM32L031x4/6
74/126 DS10668 Rev 6
DTEMP(MSI)(1) MSI oscillator frequency drift
C TA 85 °C -±3-%
DVOLT(MSI)(1) MSI oscillator frequency drift
1.65 V VDD 3.6 V, TA = 25 °C --2.5%/V
IDD(MSI)(2) MSI oscillator power consumption
MSI range 0 0.75 -
µA
MSI range 1 1 -
MSI range 2 1.5 -
MSI range 3 2.5 -
MSI range 4 4.5 -
MSI range 5 8 -
MSI range 6 15 -
tSU(MSI) MSI oscillator startup time
MSI range 0 30 -
µs
MSI range 1 20 -
MSI range 2 15 -
MSI range 3 10 -
MSI range 4 6 -
MSI range 5 5 -
MSI range 6,
Voltage range 1
and 2
3.5 -
MSI range 6,
Voltage range 3 5-
tSTAB(MSI)(2) MSI oscillator stabilization time
MSI range 0 - 40
µs
MSI range 1 - 20
MSI range 2 - 10
MSI range 3 - 4
MSI range 4 - 2.5
MSI range 5 - 2
MSI range 6,
Voltage range 1
and 2
-2
MSI range 3,
Voltage range 3 -3
fOVER(MSI) MSI oscillator frequency overshoot
Any range to
range 5 -4
MHz
Any range to
range 6 -6
1. This is a deviation for an individual part, once the initial frequency has been measured.
2. Guaranteed by characterization results.
Table 43. MSI oscillator characteristics (continued)
Symbol Parameter Condition Typ Max Unit
DS10668 Rev 6 75/126
STM32L031x4/6 Electrical characteristics
96
6.3.8 PLL characteristics
The parameters given in Table 44 are derived from tests performed under ambient
temperature and VDD supply voltage conditions summarized in Table 20.
6.3.9 Memory characteristics
RAM memory
Flash memory and data EEPROM
Table 44. PLL characteristics
Symbol Parameter
Value
Unit
Min Typ Max(1)
1. Guaranteed by characterization results.
fPLL_IN
PLL input clock(2)
2. Take care of using the appropriate multiplier factors so as to have PLL input clock values compatible with
the range defined by fPLL_OUT
.
2- 24MHz
PLL input clock duty cycle 45 - 55 %
fPLL_OUT PLL output clock 2 - 32 MHz
tLOCK
PLL input = 16 MHz
PLL VCO = 96 MHz - 115 160 µs
Jitter Cycle-to-cycle jitter - ±600 ps
IDDA(PLL) Current consumption on VDDA - 220 450
µA
IDD(PLL) Current consumption on VDD - 120 150
Table 45. RAM and hardware registers
Symbol Parameter Conditions Min Typ Max Unit
VRM Data retention mode(1)
1. Minimum supply voltage without losing data stored in RAM (in Stop mode or under Reset) or in hardware
registers (only in Stop mode).
STOP mode (or RESET) 1.65 - - V
Table 46. Flash memory and data EEPROM characteristics
Symbol Parameter Conditions Min Typ Max(1) Unit
VDD
Operating voltage
Read / Write / Erase -1.65-3.6V
tprog
Programming time for
word or half-page
Erasing - 3.28 3.94
ms
Programming - 3.28 3.94
Electrical characteristics STM32L031x4/6
76/126 DS10668 Rev 6
IDD
Average current during
the whole programming /
erase operation
TA = 25 °C, VDD = 3.6 V
- 500 700 µA
Maximum current (peak)
during the whole
programming / erase
operation
-1.52.5mA
1. Guaranteed by design.
Table 47. Flash memory and data EEPROM endurance and retention
Symbol Parameter Conditions
Value
Unit
Min(1)
1. Guaranteed by characterization results.
NCYC(2)
Cycling (erase / write)
Program memory
TA = –40°C to 105 °C
10
kcycles
Cycling (erase / write)
EEPROM data memory 100
Cycling (erase / write)
Program memory
TA = –40°C to 125 °C
0.2
Cycling (erase / write)
EEPROM data memory 2
tRET(2)
2. Characterization is done according to JEDEC JESD22-A117.
Data retention (program memory) after
10 kcycles at TA = 85 °C
TRET = +85 °C
30
years
Data retention (EEPROM data memory)
after 100 kcycles at TA = 85 °C 30
Data retention (program memory) after
10 kcycles at TA = 105 °C
TRET = +105 °C
10
Data retention (EEPROM data memory)
after 100 kcycles at TA = 105 °C
Data retention (program memory) after
200 cycles at TA = 125 °C
TRET = +125 °C
Data retention (EEPROM data memory)
after 2 kcycles at TA = 125 °C
Table 46. Flash memory and data EEPROM characteristics
Symbol Parameter Conditions Min Typ Max(1) Unit
DS10668 Rev 6 77/126
STM32L031x4/6 Electrical characteristics
96
6.3.10 EMC characteristics
Susceptibility tests are performed on a sample basis during device characterization.
Functional EMS (electromagnetic susceptibility)
While a simple application is executed on the device (toggling 2 LEDs through I/O ports).
the device is stressed by two electromagnetic events until a failure occurs. The failure is
indicated by the LEDs:
Electrostatic discharge (ESD) (positive and negative) is applied to all device pins until
a functional disturbance occurs. This test is compliant with the IEC 61000-4-2 standard.
FTB: A Burst of Fast Transient voltage (positive and negative) is applied to VDD and
VSS through a 100 pF capacitor, until a functional disturbance occurs. This test is
compliant with the IEC 61000-4-4 standard.
A device reset allows normal operations to be resumed.
The test results are given in Table 48. They are based on the EMS levels and classes
defined in application note AN1709.
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software. Please note that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for his application.
Software recommendations
The software flowchart must include the management of runaway conditions such as:
Corrupted program counter
Unexpected reset
Critical data corruption (control registers...)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the NRST pin or the oscillator pins for 1
second.
Table 48. EMS characteristics
Symbol Parameter Conditions Level/
Class
VFESD
Voltage limits to be applied on any I/O pin to
induce a functional disturbance
VDD = 3.3 V, LQFP48, TA = +25 °C,
fHCLK = 32 MHz
conforms to IEC 61000-4-2
3B
VEFTB
Fast transient voltage burst limits to be
applied through 100 pF on VDD and VSS
pins to induce a functional disturbance
VDD = 3.3 V, LQFP48, TA = +25 °C,
fHCLK = 32 MHz
conforms to IEC 61000-4-4
4A
Electrical characteristics STM32L031x4/6
78/126 DS10668 Rev 6
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behavior is detected, the software can be hardened
to prevent unrecoverable errors occurring (see application note AN1015).
Electromagnetic Interference (EMI)
The electromagnetic field emitted by the device are monitored while a simple application is
executed (toggling 2 LEDs through the I/O ports). This emission test is compliant with
IEC 61967-2 standard which specifies the test board and the pin loading.
6.3.11 Electrical sensitivity characteristics
Based on three different tests (ESD, LU) using specific measurement methods, the device is
stressed in order to determine its performance in terms of electrical sensitivity.
Electrostatic discharge (ESD)
Electrostatic discharges (a positive then a negative pulse separated by 1 second) are
applied to the pins of each sample according to each pin combination. The sample size
depends on the number of supply pins in the device (3 parts × (n+1) supply pins). This test
conforms to the ANSI/JEDEC standard.
Table 49. EMI characteristics
Symbol Parameter Conditions Monitored
frequency band
Max vs.
fOSC/fCPU Unit
8MHz/32MHz
SEMI Peak level
VDD = 3.6 V,
TA = 25 °C,
LQFP48 package
conforming to IEC61967-2
0.1 to 30 MHz 10
dBµV30 to 130 MHz 5
130 MHz to 1GHz –5
EMI Level 1.5 -
Table 50. ESD absolute maximum ratings
Symbol Ratings Conditions Class Maximum
value(1)
1. Guaranteed by characterization results.
Unit
VESD(HBM)
Electrostatic discharge
voltage (human body model)
TA = +25 °C,
conforming to
ANSI/JEDEC JS-001
22000
V
VESD(CDM)
Electrostatic discharge
voltage (charge device
model)
TA = +25 °C,
conforming to
ANSI/ESD STM5.3.1.
C4 500
(1)
DS10668 Rev 6 79/126
STM32L031x4/6 Electrical characteristics
96
Static latch-up
Two complementary static tests are required on six parts to assess the latch-up
performance:
A supply overvoltage is applied to each power supply pin
A current injection is applied to each input, output and configurable I/O pin
These tests are compliant with EIA/JESD 78A IC latch-up standard.
6.3.12 I/O current injection characteristics
As a general rule, current injection to the I/O pins, due to external voltage below VSS or
above VDD (for standard pins) must be avoided during normal product operation. However,
in order to give an indication of the robustness of the microcontroller in cases when
abnormal injection accidentally happens, susceptibility tests are performed on a sample
basis during device characterization.
Functional susceptibility to I/O current injection
While a simple application is executed on the device, the device is stressed by injecting
current into the I/O pins programmed in floating input mode. While current is injected into
the I/O pin, one at a time, the device is checked for functional failures.
The failure is indicated by an out of range parameter: ADC error above a certain limit (higher
than 5 LSB TUE), out of conventional limits of induced leakage current on adjacent pins (out
of –5 µA/+0 µA range), or other functional failure (for example reset occurrence oscillator
frequency deviation).
The test results are given in the Table 52.
Table 51. Electrical sensitivities
Symbol Parameter Conditions Class
LU Static latch-up class TA = +125 °C conforming to JESD78A II level A
Table 52. I/O current injection susceptibility
Symbol Description
Functional susceptibility
Unit
Negative
injection
Positive
injection
IINJ
Injected current on BOOT0 –0 NA(1)
1. Current injection is not possible.
mA
Injected current on PA0, PA2, PA4, PA5,
PC15, PH0 and PH1 –5 0
Injected current on any other FT and FTf
pin –5 (2)
2. It is recommended to add a Schottky diode (pin to ground) to analog pins which may potentially inject
negative currents.
NA(1)
Injected current on any other pin 5 (2) +5
Electrical characteristics STM32L031x4/6
80/126 DS10668 Rev 6
6.3.13 I/O port characteristics
General input/output characteristics
Unless otherwise specified, the parameters given in Table 53 are derived from tests
performed under the conditions summarized in Table 20. All I/Os are CMOS and TTL
compliant.
Table 53. I/O static characteristics
Symbol Parameter Conditions Min Typ Max Unit
VIL Input low level voltage
TC, FT, FTf, RST
I/Os - - 0.3VDD
V
BOOT0 pin - - 0.14VDD(1)
VIH Input high level voltage All I/Os 0.7 VDD --
Vhys
I/O Schmitt trigger voltage hysteresis
(2)
Standard I/Os - 10% VDD(3) -
BOOT0 pin - 0.01 -
Ilkg Input leakage current (4)
VSS VIN VDD
All I/Os except
PA11, PA12, BOOT0
and FTf I/Os
--±50
nA
VSS VIN VDD
PA11 and P12 I/Os - - –50/+250
VSS VIN VDD
FTf I/Os - - ±100
VDDVIN 5V
All I/Os except for
PA11, PA12, BOOT0
and FTf I/Os
--200
VDDVIN 5V
FTf I/Os --500
VDDVIN 5V
PA11, PA12 and
BOOT0
- - 10 µA
RPU Weak pull-up equivalent resistor(5) VIN = VSS 25 45 65 kΩ
RPD Weak pull-down equivalent resistor(5) VIN = VDD 25 45 65 kΩ
CIO I/O pin capacitance - - 5 - pF
1. Guaranteed by characterization.
2. Hysteresis voltage between Schmitt trigger switching levels. Guaranteed by characterization results.
3. With a minimum of 200 mV. Guaranteed by characterization results.
4. The max. value may be exceeded if negative current is injected on adjacent pins.
5. Pull-up and pull-down resistors are designed with a true resistance in series with a switchable PMOS/NMOS. This
MOS/NMOS contribution to the series resistance is minimum (~10% order).
DS10668 Rev 6 81/126
STM32L031x4/6 Electrical characteristics
96
Figure 25. VIH/VIL versus VDD (CMOS I/Os)
Figure 26. VIH/VIL versus VDD (TTL I/Os)
Output driving current
The GPIOs (general purpose input/outputs) can sink or source up to ±8 mA, and sink or
source up to ±15 mA with the non-standard VOL/VOH specifications given in Table 54 .
In the user application, the number of I/O pins which can drive current must be limited to
respect the absolute maximum rating specified in Section 6.2:
The sum of the currents sourced by all the I/Os on VDD, plus the maximum Run
consumption of the MCU sourced on VDD, cannot exceed the absolute maximum rating
IVDD(Σ) (see Table 18).
The sum of the currents sunk by all the I/Os on VSS plus the maximum Run
consumption of the MCU sunk on VSS cannot exceed the absolute maximum rating
IVSS(Σ) (see Table 18).
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Electrical characteristics STM32L031x4/6
82/126 DS10668 Rev 6
Output voltage levels
Unless otherwise specified, the parameters given in Table 54 are derived from tests
performed under ambient temperature and VDD supply voltage conditions summarized in
Table 20. All I/Os are CMOS and TTL compliant.
Table 54. Output voltage characteristics
Symbol Parameter Conditions Min Max Unit
VOL(1)
1. The IIO current sunk by the device must always respect the absolute maximum rating specified in
Table 18. The sum of the currents sunk by all the I/Os (I/O ports and control pins) must always be
respected and must not exceed ΣIIO(PIN).
Output low level voltage for an I/O
pin CMOS port(2),
IIO = +8 mA
2.7 V VDD 3.6 V
2. TTL and CMOS outputs are compatible with JEDEC standards JESD36 and JESD52.
-0.4
V
VOH(3)
3. The IIO current sourced by the device must always respect the absolute maximum rating specified in
Table 18. The sum of the currents sourced by all the I/Os (I/O ports and control pins) must always be
respected and must not exceed ΣIIO(PIN).
Output high level voltage for an
I/O pin VDD–0.4 -
VOL (1) Output low level voltage for an I/O
pin
TTL port(2),
IIO =+ 8 mA
2.7 V VDD 3.6 V
-0.4
VOH (3)(4)
4. Guaranteed by characterization results.
Output high level voltage for an
I/O pin
TTL port(2),
IIO = –6 mA
2.7 V VDD 3.6 V
2.4 -
VOL(1)(4) Output low level voltage for an I/O
pin
IIO = +15 mA
2.7 V VDD 3.6 V -1.3
VOH(3)(4) Output high level voltage for an
I/O pin
IIO = –15 mA
2.7 V VDD 3.6 V VDD–1.3 -
VOL(1)(4) Output low level voltage for an I/O
pin
IIO = +4 mA
1.65 V VDD< 3.6 V -0.45
VOH(3)(4) Output high level voltage for an
I/O pin
IIO = –4 mA
1.65 V VDD 3.6 V
VDD
0.45 -
VOLFM+(1)(4) Output low level voltage for an FTf
I/O pin in Fm+ mode
IIO = 20 mA
2.7 V VDD 3.6 V -0.4
IIO = 10 mA
1.65 V VDD 3.6 V -0.4
DS10668 Rev 6 83/126
STM32L031x4/6 Electrical characteristics
96
Input/output AC characteristics
The definition and values of input/output AC characteristics are given in Figure 27 and
Table 55, respectively.
Unless otherwise specified, the parameters given in Table 55 are derived from tests
performed under ambient temperature and VDD supply voltage conditions summarized in
Table 20.
Table 55. I/O AC characteristics(1)
OSPEEDRx
[1:0] bit value(1) Symbol Parameter Conditions Min Max(2) Unit
00
fmax(IO)out Maximum frequency(3) CL = 50 pF, VDD = 2.7 V to 3.6 V - 400
kHz
CL = 50 pF, VDD = 1.65 V to 2.7 V - 100
tf(IO)out
tr(IO)out
Output rise and fall time
CL = 50 pF, VDD = 2.7 V to 3.6 V - 125
ns
CL = 50 pF, VDD = 1.65 V to 2.7 V - 320
01
fmax(IO)out Maximum frequency(3) CL = 50 pF, VDD = 2.7 V to 3.6 V - 2
MHz
CL = 50 pF, VDD = 1.65 V to 2.7 V - 0.6
tf(IO)out
tr(IO)out
Output rise and fall time
CL = 50 pF, VDD = 2.7 V to 3.6 V - 30
ns
CL = 50 pF, VDD = 1.65 V to 2.7 V - 65
10
Fmax(IO)out Maximum frequency(3) CL = 50 pF, VDD = 2.7 V to 3.6 V - 10
MHz
CL = 50 pF, VDD = 1.65 V to 2.7 V - 2
tf(IO)out
tr(IO)out
Output rise and fall time
CL = 50 pF, VDD = 2.7 V to 3.6 V - 13
ns
CL = 50 pF, VDD = 1.65 V to 2.7 V - 28
11
Fmax(IO)out Maximum frequency(3) CL = 30 pF, VDD = 2.7 V to 3.6 V - 35
MHz
CL = 50 pF, VDD = 1.65 V to 2.7 V - 10
tf(IO)out
tr(IO)out
Output rise and fall time
CL = 30 pF, VDD = 2.7 V to 3.6 V - 6
ns
CL = 50 pF, VDD = 1.65 V to 2.7 V - 17
Fm+
configuration(4)
fmax(IO)out Maximum frequency(3)
CL = 50 pF, VDD = 2.5 V to 3.6 V
-1MHz
tf(IO)out Output fall time - 10
ns
tr(IO)out Output rise time - 30
fmax(IO)out Maximum frequency(3)
CL = 50 pF, VDD = 1.65 V to 3.6 V
-350KHz
tf(IO)out Output fall time - 15
ns
tr(IO)out Output rise time - 60
-t
EXTIpw
Pulse width of external
signals detected by the
EXTI controller
-8-ns
1. The I/O speed is configured using the OSPEEDRx[1:0] bits. Refer to the line reference manual for a description of GPIO Port
configuration register.
2. Guaranteed by design.
3. The maximum frequency is defined in Figure 27.
4. When Fm+ configuration is set, the I/O speed control is bypassed. Refer to the line reference manual for a detailed
description of Fm+ I/O configuration.
Electrical characteristics STM32L031x4/6
84/126 DS10668 Rev 6
Figure 27. I/O AC characteristics definition
6.3.14 NRST pin characteristics
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, RPU , except when it is internally driven low (see Table 56).
Unless otherwise specified, the parameters given in Table 56 are derived from tests
performed under ambient temperature and VDD supply voltage conditions summarized in
Table 20.
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Table 56. NRST pin characteristics
Symbol Parameter Conditions Min Typ Max Unit
VIL(NRST)(1)
1. Guaranteed by design.
NRST input low level voltage - VSS -0.8
V
VIH(NRST)(1) NRST input high level voltage - 1.4 - VDD
VOL(NRST)(1) NRST output low level
voltage
IOL = 2 mA
2.7 V < VDD < 3.6 V --
0.4
IOL = 1.5 mA
1.65 V < VDD < 2.7 V --
Vhys(NRST)(1) NRST Schmitt trigger voltage
hysteresis --10%V
DD(2)
2. 200 mV minimum value
-mV
RPU
Weak pull-up equivalent
resistor(3)
3. The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution to
the series resistance is around 10%.
VIN = VSS 25 45 65 kΩ
VF(NRST)(1) NRST input filtered pulse - - - 50 ns
VNF(NRST)(1) NRST input not filtered pulse - 350 - - ns
DS10668 Rev 6 85/126
STM32L031x4/6 Electrical characteristics
96
Figure 28. Recommended NRST pin protection
1. The reset network protects the device against parasitic resets.
2. The external capacitor must be placed as close as possible to the device.
3. The user must ensure that the level on the NRST pin can go below the VIL(NRST) max level specified in
Table 56. Otherwise the reset will not be taken into account by the device.
6.3.15 12-bit ADC characteristics
Unless otherwise specified, the parameters given in Table 57 are values derived from tests
performed under ambient temperature, fPCLK frequency and VDDA supply voltage conditions
summarized in Table 20: General operating conditions.
Note: It is recommended to perform a calibration after each power-up.
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Table 57. ADC characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDDA
Analog supply voltage for
ADC on
Fast channel 1.65 - 3.6
V
Standard channel 1.75(1) -3.6
IDDA (ADC)
Current consumption of the
ADC on VDDA
1.14 Msps - 200 -
µA
10 ksps - 40 -
Current consumption of the
ADC on VDD(2)
1.14 Msps - 70 -
10 ksps - 1 -
fADC ADC clock frequency
Voltage scaling Range 1 0.14 - 16
MHzVoltage scaling Range 2 0.14 - 8
Voltage scaling Range 3 0.14 - 4
fS(3) Sampling rate 0.05 - 1.14 MHz
fTRIG(3) External trigger frequency
fADC = 16 MHz - - 941 kHz
--171/f
ADC
VAIN Conversion voltage range 0 - VDDA V
RAIN(3) External input impedance See Equation 1 and
Table 58 for details --50kΩ
RADC(3)(4) Sampling switch resistance - - 1 kΩ
CADC(3) Internal sample and hold
capacitor --8pF
Electrical characteristics STM32L031x4/6
86/126 DS10668 Rev 6
Equation 1: RAIN max formula
The formula above (Equation 1) is used to determine the maximum external impedance
allowed for an error below 1/4 of LSB. Here N = 12 (from 12-bit resolution).
tCAL(3) Calibration time
fADC = 16 MHz 5.2 µs
83 1/fADC
WLATENCY ADC_DR register write
latency
ADC clock = HSI16
1.5 ADC
cycles + 2
fPCLK cycles
-
1.5 ADC
cycles + 3
fPCLK cycles -
ADC clock = PCLK/2 - 4.5 - fPCLK
cycle
ADC clock = PCLK/4 - 8.5 - fPCLK
cycle
tlatr(3) Trigger conversion latency
fADC = fPCLK/2 = 16 MHz 0.266 µs
fADC = fPCLK/2 8.5 1/fPCLK
fADC = fPCLK/4 = 8 MHz 0.516 µs
fADC = fPCLK/4 16.5 1/fPCLK
fADC = fHSI16 = 16 MHz 0.252 - 0.260 µs
JitterADC ADC jitter on trigger
conversion fADC = fHSI16 -1-1/f
HSI16
tS(3) Sampling time
fADC = 16 MHz 0.093 - 10.03 µs
1.5 - 239.5 1/fADC
tSTAB(3) Power-up time 0 0 1 µs
tConV(3) Total conversion time
(including sampling time)
fADC = 16 MHz 0.875 10.81 µs
14 to 173 (tS for sampling +12.5 for
successive approximation) 1/fADC
1. VDDA minimum value can be decreased in specific temperature conditions. Refer to Table 58: RAIN max for fADC = 16
MHz.
2. A current consumption proportional to the APB clock frequency has to be added (see Table 34: Peripheral current
consumption in Run or Sleep mode).
3. Guaranteed by design.
4. Standard channels have an extra protection resistance which depends on supply voltage. Refer to Table 58: RAIN max for
fADC = 16 MHz.
Table 57. ADC characteristics (continued)
Symbol Parameter Conditions Min Typ Max Unit
RAIN
TS
fADC CADC 2N2+
()ln××
----------------------------------------------------------------RADC
<
AIN fADC
DS10668 Rev 6 87/126
STM32L031x4/6 Electrical characteristics
96
Table 58. RAIN max for fADC = 16 MHz(1)
Ts
(cycles)
tS
(µs)
RAIN max for
fast channels
(kΩ)
RAIN max for standard channels (kΩ)
VDD >
2.7 V
VDD >
2.4 V
VDD >
2.0 V
VDD >
1.8 V
VDD >
1.75 V
VDD > 1.65 V
and
TA > 10 °C
VDD > 1.65 V
and
TA > 25 °C
1.5 0.09 0.5 < 0.1 NA NA NA NA NA NA
3.5 0.22 1 0.2 < 0.1 NA NA NA NA NA
7.5 0.47 2.5 1.7 1.5 < 0.1 NA NA NA NA
12.5 0.78 4 3.2 3 1 NA NA NA NA
19.5 1.22 6.5 5.7 5.5 3.5 NA NA NA < 0.1
39.5 2.47 13 12.2 12 10 NA NA NA 5
79.5 4.97 27 26.2 26 24 < 0.1 NA NA 19
160.5 10.03 50 49.2 49 47 32 < 0.1 < 0.1 42
1. Guaranteed by design.
Table 59. ADC accuracy(1)(2)(3)
Symbol Parameter Conditions Min Typ Max Unit
ET Total unadjusted error
1.65 V < VDDA < 3.6 V, range
1/2/3
-2 4
LSB
EO Offset error - 1 2.5
EG Gain error - 1 2
EL Integral linearity error - 1.5 2.5
ED Differential linearity error - 1 1.5
ENOB
Effective number of bits 10.2 11
bits
Effective number of bits (16-bit mode
oversampling with ratio =256)(4) 11.3 12.1 -
SINAD Signal-to-noise distortion 63 69 -
dBSNR
Signal-to-noise ratio 63 69 -
Signal-to-noise ratio (16-bit mode
oversampling with ratio =256)(4) 70 76 -
THD Total harmonic distortion - –85 –73
1. ADC DC accuracy values are measured after internal calibration.
2. ADC Accuracy vs. Negative Injection Current: Injecting negative current on any of the standard (non-robust) analog input
pins must be avoided as this significantly reduces the accuracy of the conversion being performed on another analog input.
It is recommended to add a Schottky diode (pin to ground) to standard analog pins which may potentially inject negative
current.
Any positive injection current within the limits specified for IINJ(PIN) and ΣIINJ(PIN) in Section 6.3.12 does not affect the ADC
accuracy.
3. Better performance may be achieved in restricted VDDA, frequency and temperature ranges.
4. This number is obtained by the test board without additional noise, resulting in non-optimized value for oversampling mode.
«HF;
Electrical characteristics STM32L031x4/6
88/126 DS10668 Rev 6
Figure 29. ADC accuracy characteristics
Figure 30. Typical connection diagram using the ADC
1. Refer to Table 57: ADC characteristics for the values of RAIN, RADC and CADC.
2. Cparasitic represents the capacitance of the PCB (dependent on soldering and PCB layout quality) plus the
pad capacitance (roughly 7 pF). A high Cparasitic value will downgrade conversion accuracy. To remedy
this, fADC must be reduced.
6.3.16 Temperature sensor characteristics
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Table 60. Temperature sensor calibration values
Calibration value name Description Memory address
TS_CAL1
TS ADC raw data acquired at
temperature of 30 °C,
VDDA= 3 V
0x1FF8 007A - 0x1FF8 007B
TS_CAL2
TS ADC raw data acquired at
temperature of 130 °C
VDDA= 3 V
0x1FF8 007E - 0x1FF8 007F
DS10668 Rev 6 89/126
STM32L031x4/6 Electrical characteristics
96
6.3.17 Comparators
Table 61. Temperature sensor characteristics
Symbol Parameter Min Typ Max Unit
TL(1)
1. Guaranteed by characterization results.
VSENSE linearity with temperature - ±1±C
Avg_Slope(1) Average slope 1.48 1.61 1.75 mV/°C
V130 Voltage at 130°C ±5°C(2)
2. Measured at VDD = 3 V ±10 mV. V130 ADC conversion result is stored in the TS_CAL2 byte.
640 670 700 mV
IDDA(TEMP)(3) Current consumption - 3.4 6 µA
tSTART(3)
3. Guaranteed by design.
Startup time - - 10
µs
TS_temp(4)(3)
4. Shortest sampling time can be determined in the application by multiple iterations.
ADC sampling time when reading the
temperature 10 - -
Table 62. Comparator 1 characteristics
Symbol Parameter Conditions Min(1) Typ Max(1)
1. Guaranteed by characterization.
Unit
VDDA Analog supply voltage - 1.65 3.6 V
R400K R400K value - - 400 -
kΩ
R10K R10K value - - 10 -
VIN
Comparator 1 input
voltage range -0.6-V
DDA V
tSTART Comparator startup time - - 7 10
µs
td Propagation delay(2)
2. The delay is characterized for 100 mV input step with 10 mV overdrive on the inverting input, the non-
inverting input set to the reference.
--310
Voffset Comparator offset - - ±3±10 mV
dVoffset/dt
Comparator offset
variation in worst voltage
stress conditions
VDDA = 3.6 V
VIN+ = 0 V
VIN- = VREFINT
TA = 25 °C
0 1.5 10 mV/1000 h
ICOMP1 Current consumption(3)
3. Comparator consumption only. Internal reference voltage not included.
- - 160 260 nA
Electrical characteristics STM32L031x4/6
90/126 DS10668 Rev 6
6.3.18 Timer characteristics
TIM timer characteristics
The parameters given in the Table 64 are guaranteed by design.
Refer to Section 6.3.13: I/O port characteristics for details on the input/output alternate
function characteristics (output compare, input capture, external clock, PWM output).
Table 63. Comparator 2 characteristics
Symbol Parameter Conditions Min Typ Max(1)
1. Guaranteed by characterization results.
Unit
VDDA Analog supply voltage - 1.65 - 3.6 V
VIN
Comparator 2 input voltage
range -0-V
DDA V
tSTART Comparator startup time
Fast mode - 15 20
µs
Slow mode - 20 25
td slow
Propagation delay(2) in slow
mode
2. The delay is characterized for 100 mV input step with 10 mV overdrive on the inverting input, the non-
inverting input set to the reference.
1.65 V VDDA 2.7 V - 1.8 3.5
2.7 V VDDA 3.6 V - 2.5 6
td fast
Propagation delay(2) in fast
mode
1.65 V VDDA 2.7 V - 0.8 2
2.7 V VDDA 3.6 V - 1.2 4
Voffset Comparator offset error - - ±4±20 mV
dThreshold/dt Threshold voltage temperature
coefficient
VDDA = 3.3V
TA = 0 to 50 °C
V- =VREFINT
,
3/4 VREFINT
,
1/2 VREFINT
,
1/4 VREFINT
.
-15 30
ppm
/°C
ICOMP2 Current consumption(3)
3. Comparator consumption only. Internal reference voltage (necessary for comparator operation) is not
included.
Fast mode - 3.5 5
µA
Slow mode - 0.5 2
Table 64. TIMx(1) characteristics
Symbol Parameter Conditions Min Max Unit
tres(TIM) Timer resolution time
-1-t
TIMxCLK
fTIMxCLK = 32 MHz 31.25 - ns
fEXT
Timer external clock
frequency on CH1 to CH4
-0f
TIMxCLK/2 MHz
fTIMxCLK = 32 MHz 0 16 MHz
ResTIM Timer resolution - - 16 bit
0m
DS10668 Rev 6 91/126
STM32L031x4/6 Electrical characteristics
96
6.3.19 Communications interfaces
I2C interface characteristics
The I2C interface meets the timings requirements of the I2C-bus specification and user
manual rev. 03 for:
Standard-mode (Sm) : with a bit rate up to 100 kbit/s
Fast-mode (Fm) : with a bit rate up to 400 kbit/s
Fast-mode Plus (Fm+) : with a bit rate up to 1 Mbit/s.
The I2C timing requirements are guaranteed by design when the I2C peripheral is properly
configured (refer to the reference manual for details). The SDA and SCL I/O requirements
are met with the following restrictions: the SDA and SCL I/O pins are not "true" open-drain.
When configured as open-drain, the PMOS connected between the I/O pin and VDDIOx is
disabled, but is still present. Only FTf I/O pins support Fm+ low level output current
maximum requirement (refer to Section 6.3.13: I/O port characteristics for the I2C I/Os
characteristics).
All I2C SDA and SCL I/Os embed an analog filter (see Table 65 for the analog filter
characteristics).
The analog spike filter is compliant with I2C timings requirements only for the following
voltage ranges:
Fast mode Plus: 2.7 V
VDD 3.6 V and voltage scaling Range 1
Fast mode:
–2V VDD 3.6 V and voltage scaling Range 1 or Range 2.
–V
DD < 2 V, voltage scaling Range 1 or Range 2, Cload < 200 pF.
In other ranges, the analog filter must be disabled. The digital filter can be used instead.
Note: In Standard mode, no spike filter is required.
tCOUNTER
16-bit counter clock
period when internal clock
is selected (timer’s
prescaler disabled)
- 1 65536 tTIMxCLK
fTIMxCLK = 32 MHz 0.0312 2048 µs
tMAX_COUNT Maximum possible count
- - 65536 × 65536 tTIMxCLK
fTIMxCLK = 32 MHz - 134.2 s
1. TIMx is used as a general term to refer to the TIM2, TIM21, and TIM22 timers.
Table 64. TIMx(1) characteristics (continued)
Symbol Parameter Conditions Min Max Unit
Table 65. I2C analog filter characteristics(1)
1. Guaranteed by characterization results.
Symbol Parameter Conditions Min Max Unit
tAF
Maximum pulse width of spikes that
are suppressed by the analog filter
Range 1
50(2)
2. Spikes with widths below tAF(min) are filtered.
100(3)
nsRange 2 -
Range 3 -
Electrical characteristics STM32L031x4/6
92/126 DS10668 Rev 6
SPI characteristics
Unless otherwise specified, the parameters given in the following tables are derived from
tests performed under ambient temperature, fPCLKx frequency and VDD supply voltage
conditions summarized in Table 20.
Refer to Section 6.3.12: I/O current injection characteristics for more details on the
input/output alternate function characteristics (NSS, SCK, MOSI, MISO).
3. Spikes with widths above tAF(max) are not filtered
Table 66. SPI characteristics in voltage Range 1 (1)
Symbol Parameter Conditions Min Typ Max Unit
fSCK
1/tc(SCK)
SPI clock frequency
Master mode
--
16
MHz
Slave mode receiver 16
Slave mode Transmitter
1.71<VDD<3.6V --12
(2)
Slave mode Transmitter
2.7<VDD<3.6V --16
(2)
Duty(SCK)
Duty cycle of SPI clock
frequency Slave mode 30 50 70 %
tsu(NSS) NSS setup time Slave mode, SPI presc = 2 4*Tpclk - -
ns
th(NSS) NSS hold time Slave mode, SPI presc = 2 2*Tpclk - -
tw(SCKH)
tw(SCKL)
SCK high and low time Master mode Tpclk–2 Tpclk Tpclk+2
tsu(MI) Data input setup time
Master mode 8.5 - -
tsu(SI) Slave mode 8.5 - -
th(MI) Data input hold time
Master mode 6 - -
th(SI) Slave mode 1 - -
ta(SO Data output access time Slave mode 15 - 36
tdis(SO) Data output disable time Slave mode 10 - 30
tv(SO) Data output valid time
Slave mode 1.71<VDD<3.6V - 29 41
Slave mode 2.7<VDD<3.6V - 22 28
tv(MO) Master mode - 10 17
th(SO) Data output hold time
Slave mode 9 - -
th(MO) Master mode 3 - -
1. Guaranteed by characterization results.
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.
DS10668 Rev 6 93/126
STM32L031x4/6 Electrical characteristics
96
Table 67. SPI characteristics in voltage Range 2 (1)
Symbol Parameter Conditions Min Typ Max Unit
fSCK
1/tc(SCK)
SPI clock frequency
Master mode
--
8
MHz
Slave mode Transmitter
1.65<VDD<3.6V 8
Slave mode Transmitter
2.7<VDD<3.6V 8(2)
Duty(SCK)
Duty cycle of SPI clock
frequency Slave mode 30 50 70 %
tsu(NSS) NSS setup time Slave mode, SPI presc = 2 4*Tpclk - -
ns
th(NSS) NSS hold time Slave mode, SPI presc = 2 2*Tpclk - -
tw(SCKH)
tw(SCKL)
SCK high and low time Master mode Tpclk–2 Tpclk Tpclk+2
tsu(MI) Data input setup time
Master mode 12 - -
tsu(SI) Slave mode 11 - -
th(MI) Data input hold time
Master mode 6.5 - -
th(SI) Slave mode 2 - -
ta(SO Data output access time Slave mode 18 - 52
tdis(SO) Data output disable time Slave mode 12 - 42
tv(SO) Data output valid time
Slave mode -40 55
Master mode - 16 26
tv(MO) Data output hold time
Slave mode 12 - -
th(SO) Master mode 4 - -
1. Guaranteed by characterization results.
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.
Electrical characteristics STM32L031x4/6
94/126 DS10668 Rev 6
Table 68. SPI characteristics in voltage Range 3 (1)
Symbol Parameter Conditions Min Typ Max Unit
fSCK
1/tc(SCK)
SPI clock frequency
Master mode
--
2
MHz
Slave mode 2(2)
Duty(SCK)
Duty cycle of SPI clock
frequency Slave mode 30 50 70 %
tsu(NSS) NSS setup time Slave mode, SPI presc = 2 4*Tpclk - -
ns
th(NSS) NSS hold time Slave mode, SPI presc = 2 2*Tpclk - -
tw(SCKH)
tw(SCKL)
SCK high and low time Master mode Tpclk–2 Tpclk Tpclk+2
tsu(MI) Data input setup time
Master mode 28.5 - -
tsu(SI) Slave mode 22 - -
th(MI) Data input hold time
Master mode 7 - -
th(SI) Slave mode 5 - -
ta(SO Data output access time Slave mode 30 - 70
tdis(SO) Data output disable time Slave mode 40 - 80
tv(SO) Data output valid time
Slave mode - 53 86
Master mode - 30 54
tv(MO) Data output hold time
Slave mode 18 - -
th(SO) Master mode 8 - -
1. Guaranteed by characterization results.
2. The maximum SPI clock frequency in slave transmitter mode is determined by the sum of tv(SO) and tsu(MI) which has to fit
into SCK low or high phase preceding the SCK sampling edge. This value can be achieved when the SPI communicates
with a master having tsu(MI) = 0 while Duty(SCK) = 50%.
DS10668 Rev 6 95/126
STM32L031x4/6 Electrical characteristics
96
Figure 31. SPI timing diagram - slave mode and CPHA = 0
Figure 32. SPI timing diagram - slave mode and CPHA = 1(1)
1. Measurement points are done at CMOS levels: 0.3VDD and 0.7VDD.
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Figure 33. SPI timing diagram - master mode(1)
1. Measurement points are done at CMOS levels: 0.3VDD and 0.7VDD.
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STM32L031x4/6 Package information
120
7 Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at www.st.com.
ECOPACK® is an ST trademark.
7.1 LQFP48 package information
Figure 34. LQFP48, 7 x 7 mm, 48-pin low-profile quad flat package outline
1. Drawing is not to scale.
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Table 69. LQFP48 - 48-pin low-profile quad flat package, 7 x 7 mm, package
mechanical data
Symbol
millimeters inches(1)
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Min Typ Max Min Typ Max
A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 1.400 1.450 0.0531 0.0551 0.0571
b 0.170 0.220 0.270 0.0067 0.0087 0.0106
c 0.090 - 0.200 0.0035 - 0.0079
D 8.800 9.000 9.200 0.3465 0.3543 0.3622
D1 6.800 7.000 7.200 0.2677 0.2756 0.2835
D3 - 5.500 - - 0.2165 -
E 8.800 9.000 9.200 0.3465 0.3543 0.3622
E1 6.800 7.000 7.200 0.2677 0.2756 0.2835
E3 - 5.500 - - 0.2165 -
e - 0.500 - - 0.0197 -
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
k 0°3.5°7° 0°3.5°7°
ccc - - 0.080 - - 0.0031
DS10668 Rev 6 99/126
STM32L031x4/6 Package information
120
Figure 35. LQFP48 recommended footprint
1. Dimensions are expressed in millimeters.
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100/126 DS10668 Rev 6
LQFP48 device marking
The following figure gives an example of topside marking versus pin 1 position identifier
location.
Other optional marking or inset/upset marks, which depends assembly location, are not
indicated below.
Figure 36. Example of LQFP48 marking (package top view)
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.
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STM32L031x4/6 Package information
120
7.2 UFQFPN48 package information
Figure 37. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package outline
1. Drawing is not to scale.
2. All leads/pads must also be soldered to the PCB to improve the lead/pad solder joint life.
3. There is an exposed die pad on the underside of the UFQFPN package. It is recommended to connect and
solder this back-side pad to PCB ground.
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102/126 DS10668 Rev 6
Figure 38. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package recommended footprint
1. Dimensions are expressed in millimeters.
Table 70. UFQFPN48 - 48-lead, 7x7 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package mechanical data
Symbol
millimeters inches(1)
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Min Typ Max Min Typ Max
A 0.500 0.550 0.600 0.0197 0.0217 0.0236
A1 0.000 0.020 0.050 0.0000 0.0008 0.0020
D 6.900 7.000 7.100 0.2717 0.2756 0.2795
E 6.900 7.000 7.100 0.2717 0.2756 0.2795
D2 5.500 5.600 5.700 0.2165 0.2205 0.2244
E2 5.500 5.600 5.700 0.2165 0.2205 0.2244
L 0.300 0.400 0.500 0.0118 0.0157 0.0197
T - 0.152 - - 0.0060 -
b 0.200 0.250 0.300 0.0079 0.0098 0.0118
e - 0.500 - - 0.0197 -
ddd - - 0.080 - - 0.0031
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DS10668 Rev 6 103/126
STM32L031x4/6 Package information
120
UFQFPN48 device marking
The following figure gives an example of topside marking versus pin 1 position identifier
location.
Other optional marking or inset/upset marks, which depends assembly location, are not
indicated below.
Figure 39. Example of UFQFPN48 marking (package top view)
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.
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7.3 LQFP32 package information
Figure 40. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package outline
1. Drawing is not to scale.
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STM32L031x4/6 Package information
120
Figure 41. LQFP32 recommended footprint
1. Dimensions are expressed in millimeters.
Table 71. LQFP32, 7 x 7 mm, 32-pin low-profile quad flat package mechanical data
Symbol
millimeters inches(1)
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Min Typ Max Min Typ Max
A - - 1.600 - - 0.0630
A1 0.050 - 0.150 0.0020 - 0.0059
A2 1.350 1.400 1.450 0.0531 0.0551 0.0571
b 0.300 0.370 0.450 0.0118 0.0146 0.0177
c 0.090 - 0.200 0.0035 - 0.0079
D 8.800 9.000 9.200 0.3465 0.3543 0.3622
D1 6.800 7.000 7.200 0.2677 0.2756 0.2835
D3 - 5.600 - - 0.2205 -
E 8.800 9.000 9.200 0.3465 0.3543 0.3622
E1 6.800 7.000 7.200 0.2677 0.2756 0.2835
E3 - 5.600 - - 0.2205 -
e - 0.800 - - 0.0315 -
L 0.450 0.600 0.750 0.0177 0.0236 0.0295
L1 - 1.000 - - 0.0394 -
k 0°3.5°7° 0°3.5°7°
ccc - - 0.100 - - 0.0039
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106/126 DS10668 Rev 6
LQFP32 device marking
The following figure gives an example of topside marking versus pin 1 position identifier
location.
Other optional marking or inset/upset marks, which depends assembly location, are not
indicated below.
Figure 42. Example of LQFP32 marking (package top view)
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.
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STM32L031x4/6 Package information
120
7.4 UFQFPN32 package information
Figure 43. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package outline
1. Drawing is not to scale.
2. There is an exposed die pad on the underside of the UFQFPN package. It is recommended to connect and
solder this backside pad to PCB ground.
Table 72. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package mechanical data
Symbol
millimeters inches(1)
1. Values in inches are converted from mm and rounded to 4 decimal digits.
Min Typ Max Min Typ Max
A 0.500 0.550 0.600 0.0197 0.0217 0.0236
A1 - - 0.050 - - 0.0020
A3 - 0.152 - - 0.0060 -
b 0.180 0.230 0.280 0.0071 0.0091 0.0110
D 4.900 5.000 5.100 0.1929 0.1969 0.2008
D1 3.400 3.500 3.600 0.1339 0.1378 0.1417
D2 3.400 3.500 3.600 0.1339 0.1378 0.1417
E 4.900 5.000 5.100 0.1929 0.1969 0.2008
E1 3.400 3.500 3.600 0.1339 0.1378 0.1417
E2 3.400 3.500 3.600 0.1339 0.1378 0.1417
e - 0.500 - - 0.0197 -
L 0.300 0.400 0.500 0.0118 0.0157 0.0197
ddd - - 0.080 - - 0.0031
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Package information STM32L031x4/6
108/126 DS10668 Rev 6
Figure 44. UFQFPN32 - 32-pin, 5x5 mm, 0.5 mm pitch ultra thin fine pitch quad flat
package recommended footprint
1. Dimensions are expressed in millimeters.
UFQFPN32 device marking
The following figure gives an example of topside marking versus pin 1 position identifier
location.
Other optional marking or inset/upset marks, which depends assembly location, are not
indicated below.
Figure 45. Example of UFQFPN32 marking (package top view)
1. Parts marked as “ES”, “E” or accompanied by an Engineering Sample notification letter, are not yet
qualified and therefore not yet ready to be used in production and any consequences deriving from such
usage will not be at ST charge. In no event, ST will be liable for any customer usage of these engineering
samples in production. ST Quality has to be contacted prior to any decision to use these Engineering
samples to run qualification activity.
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DS10668 Rev 6 109/126
STM32L031x4/6 Package information
120
7.5 UFQFPN28 package information
Figure 46. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package outline
1. Drawing is not to scale.
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Table 73. UFQPN28 - 28-lead, 4 x 4 mm, 0.5 mm pitch, ultra thin fine pitch quad flat
package mechanical data(1)
Symbol
millimeters inches
Min Typ Max Min Typ Max
A 0.500 0.550 0.600 0.0197 0.0217 0.0236
A1 - 0.000 0.050 - 0.0000 0.0020
D 3.900 4.000 4.100 0.1535 0.1575 0.1614
D1 2.900 3.000 3.100 0.1142 0.1181 0.1220
E 3.900 4.000 4.100 0.1535 0.1575 0.1614
E1 2.900 3.000 3.100 0.1142 0.1181 0.1220
L 0.300