The PCF8523 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power consumption. Data is transferred serially via an I²C-bus with a maximum data rate of 1000 kbit/s. Alarm and timer functions are available with the possibility to generate a wake-up signal on an interrupt pin. An offset register allows fine-tuning of the clock. The PCF8523 has a backup battery switch-over circuit, which detects power failures and automatically switches to the battery supply when a power failure occurs.

Features

• Ultra low power consumption: 120 nA @ 3 V
• Clock operating voltage: 1.2 V to 5.5 V
• 2 line bi-directional 1 MHz Fast-mode Plus I²C interface
• Battery backup input pin and switch-over circuitry
• Integrated oscillator load capacitors for CL = 7 and 12.5 pF
• Second countdown timer with interrupt output

Applications

• Time keeping application
• Battery powered devices
• Metering
• High duration timers
• Daily alarms
• Low standby power applications

The PCF2123 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power applications. Data is transferred serially via a Serial Peripheral Interface (SPI-bus) with a maximum data rate of 6.25 Mbit/s. An alarm and timer function is also available providing the possibility to generate a wake-up signal on an interrupt pin. An offset register allows fine tuning of the clock.

Features

• Ultra low power consumption: 100 nA @ 2 V
• Clock operating voltage: 1.1 to 5.5 V
• 3-line SPI with separate, combinable data I/O
• Serial interface (at V_DD = 1.6 to 5.5 V)
• Free programmable timer and alarm with interrupt capability
• Integrated oscillator load capacitors for C_L = 7 pF

Applications

• Time keeping application
• Battery powered devices
• Metering
• High duration timers
• Daily alarms
• Low standby power applications