Innovative Current Sensor ICs

For Industrial, Consumer and Computer Applications (IC&C)

Overview

Current Sensor Packaging Technology Overview

Allegro MicroSystems, LLC. has a long history of packaging innovation for current sensor IC solutions.

For measuring less than 50 A currents, Allegro employs its patented flip-chip current sensor assembly technology for its integrated current sensor ICs. This packaging technique provides several major benefits to any circuit designer: increased sensitivity, high galvanic isolation, low primary resistance, and enables the use of standard, surface-mount packages. By flipping the die inside the package, the Hall-Effect sensor IC is placed as close as possible to the current conductor, thereby increasing the magnetic field that it sees. Second, the IC is electrically isolated from the primary conductor, providing galvanic isolation up to 3600 VRMS for 60 seconds. This enables high-side current monitoring without the need for additional components to provide the isolation barrier necessary to interface the current measurement circuit with other low-voltage circuits. Third, the primary conductor design is independent of the IC itself, so that its shape can be optimized for low resistance, <=1 mΩ, reducing power losses in the system. Finally, these parts are all manufactured in surface-mount packages with JEDEC standard footprints, simplifying assembly for high-volume applications.

Figure 1: Flip-chip  current sensor IC assembly

Figure 1: Flip-chip current sensor IC assembly - Top view

For 50 A to 200 A current ranges, Allegro has created its proprietary CB package. The CB package integrates a copper primary conductor and a linear Hall-Effect current sensor IC in a single through-hole package. This provides an extremely robust solution that can handle up to 200 A continuously and pulses up to 1200 A.

The complete assembly is calibrated at the factory, eliminating the need for the customer to program the part. These parts are UL recognized and provide superior galvanic isolation, with a dielectric withstand voltage of 4800 VRMS for 60 seconds, basic isolation of 700 VRMS and a reinforced isolation rating of 450 VRMS. Lastly, the ultra-low resistance (typical = 100 µΩ) helps minimize power losses in high-current applications.

Allegro also offers Hall-Effect current sensor ICs in SIP packages for integration with a magnetic concentrator to create custom current sensing assemblies. Allegro has recently developed an ultra-thin 1 mm thick KT package to enable magnetic concentrators with very small air gaps and therefore very-high gain.

Allegro Current Sensor Packaging

Figure 2: Current sensor IC package options


Digital Temperature Compensation Overview

Allegro’s patented digital temperature compensation circuitry greatly improves both sensitivity and quiescent voltage output (QVO) error performance over a wide operating temperature range. The sensitivity and QVO of each part is measured at final test at both room temperature and hot (85°C ~ 150°C depending on the part), and the necessary compensation coefficients required to insure a flat response over the full operating temperature range are stored in EEPROM memory for both sensitivity and QVO.

Typical signal chain for current sensor IC with digital temperature compensation

Figure 3: Typical signal chain for current sensor IC with digital temperature compensation

Allegro achieves ±1% typical total error performance from 25°C ~ 150°C with the use of this new technology. By performing this calibration at final test, Allegro removes the need to do any temperature calibration of the parts once they are mounted on your PCB, making it easier to design into any application.

It is important to note that the temperature compensation is done in parallel with the analog signal path, so there is no reduction in the overall system bandwidth as a result of this new temperature compensation circuitry. When compared to previous generations of products, this circuitry results in much more accurate and stable output signal performance without compromising the response time of the output signal.

See the plots below for typical sensitivity, QVO and total error performance for the ACS723LLCTR-20AB-T product, one of the most recent current sensor ICs from Allegro that incorporates this new digital temperature compensation technology.

ACS723LLCTR-20AB-T Total Error vs. Temperature

ACS723LLCTR-20AB-T QVO Error vs. Temperature

ACS723LLCTR-20AB-T QVO Error vs. Temperature

ACS723LLCTR-20AB-T Sensitivity Error vs. Temperature

ACS723LLCTR-20AB-T Sensitivity Error vs. Temperature

Typical performance characteristics

Figure 4: Typical performance characteristics for a current sensor IC with digital temperature compensation

Motor Control Applications

Allegro Motor Control Applications

Allegro’s current sensor ICs can be used in several locations in a typical motor drive application due to their galvanic isolation and good dV/dt performance.

Due to their high galvanic isolation, Allegro's current sensor ICs are well suited to measuring the phase currents in a motor directly. This simplifies the control (no need to recreate the phase currents from indirect measurements) and reduces the bandwidth requirements on the current sensor, leading to a lower noise solution. The low resistance primary conductor, <= 1mOhm, translates into low power losses. The surface-mount packages make assembly cheaper and more reliable.

Parts like the ACS710, ACS711, and ACS716 also include integrated fault outputs that can be used to detect short circuits or other over current conditions.

Features
  • High bandwidth, low noise analog outputs – up to 120 kHz
  • High galvanic isolation – up to 3 kV dielectric withstand strength
  • High dV/dt immunity due to integrated shield in flip-chip devices
  • Low resistance on the primary conductor – 0.65 mΩ ~ 1 mΩ
  • Dedicated fault pin available on selected devices

Key Devices: ACS717/ACS718 | ACS710 | ACS716 | ACS722 | ACS723 | ACS726 | ACS711

ACS717 and ACS718 - linear current sensor ICs come in a high-isolation MA package ideal for space-constrained applications

Allegro ACS711

Benefits

  • IEC/UL 60950-1 Ed. 2 certified to:
    • Dielectric strength = 4800 VRMS (tested for 60 seconds)
    • Basic isolation = 1550 VPEAK
    • Reinforced isolation = 800 VPEAK
  • Small footprint, low-profile SOIC16 wide-body package suitable for space-constrained applications that require high-galvanic isolation
  • 0.85 mΩ primary conductor for low power loss and high inrush current withstand capability
  • Low, 350 µARMS/√Hz noise density results in typical input referred noise of 70 mA (RMS) at max bandwidth (40 kHz)
  • 3.3 V (ACS717) and 5.0 V (ACS718) single supply operation
  • Output voltage proportional to AC or DC current
  • Factory-trimmed sensitivity and quiescent output voltage for improved accuracy
  • Chopper stabilization results in extremely stable quiescent output voltage
  • Ratiometric output from supply voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS717 Bidirectional ±10 to 20 4800 3.3 40 K SOICW-16
ACS718 Bidirectional ±10 to 20 4800 6 40 K SOICW-16

ACS710 - 5 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation

Allegro ACS710

Benefits

  • Small footprint package suitable for space-constrained applications
  • 1 mΩ primary conductor resistance for low power loss
  • High isolation voltage, suitable for line-powered applications
  • User-adjustable Overcurrent Fault level
  • 3 to 5.5 V, single-supply operation
  • Ratiometric output from supply voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS710 Bidirectional ±12 to 75 3000 3.3 ~ 5 120 K SOIC-16

ACS716 - 3.3 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation

Allegro ACS716

Benefits

  • Small footprint package suitable for space-constrained applications
  • 1 mΩ primary conductor resistance for low power loss
  • High isolation voltage, suitable for line-powered applications
  • User-adjustable Overcurrent Fault level
  • 3 to 3.6 V, single-supply operation
  • Factory trimmed sensitivity and quiescent output voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS716 Bidirectional ±12 to 75 3000 3.3 120 K SOIC-16

ACS722 - 3.3 V, 80 kHz current sensor IC w/ digital temperature compensation

Allegro ACS722

Benefits

  • 0.65 mΩ primary conductor resistance for low power loss and high inrush current withstand capability
  • 3 to 3.6 V, single-supply operation
  • Output voltage proportional to AC or DC current
  • Nearly-zero magnetic hysteresis
  • Ratiometric output from supply voltage
  • Small footprint, low-profile SOIC8 package suitable for space-constrained applications
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS722 Bidirectional & Unidirectional ±5 to 40 2400 3.3 80 L SOIC-8

ACS723 - 5 V, 80 kHz current sensor IC w/ digital temperature compensation

Allegro ACS723

Benefits

  • Pin-selectable band width: 80 kHz for high bandwidth applications or 20 kHz for low noise performance.
  • 0.65 mΩ primary conductor resistance for low power loss and high inrush current withstand capability
  • Small footprint, low-profile SOIC8 package suitable for space-constrained applications
  • 4.5 to 5.5 V, single-supply operation
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS723 Bidirectional & Unidirectional 0~10 to 0~40 2400 5 80 L SOIC-8

ACS726 - Differential output current sensor IC w/ digital temperature compensation

Allegro ACS726

Benefits

  • Fully differential architecture for improved immunity to offset drift and common-mode noise
  • 1.1 mΩ primary conductor resistance for low power loss and high inrush current withstanding capability
  • Small footprint, low-profile QSOP24 package suitable for space-constrained applications
  • 3 to 3.6 V, single-supply operation
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS726 Bidirectional ±20, ±40 2100 3.3 120 L QSOP-24

ACS711 - Price competitive current sensor IC for low-side sensing

Allegro ACS711

Benefits

  • Economical low- and high-side current sensing
  • Output voltage proportional to AC or DC currents
  • Low-noise analog signal path
  • Small footprint, low-profile SOIC8 and QFN packages
  • Integrated electrostatic shield for output stability
  • No external sense resistor required; single-package solution
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS711 Bidirectional ±12.5 to 32 <100 VDC 3.3 ~ 5 100 E, K QFN-12
SOIC-8

Solar Microinverters

Allegro Solar Microinverters

In any microinverter for use with solar panels, there are multiple stages where current sensing is needed for efficient control.

The DC/DC converter stage requires current sensor ICs that can accurately sense the current flowing in the DC bus, withstand high dV/dt events, and provide the necessary functional isolation to survive operation at 400 VDC or greater.

With increasing demands on the accuracy of reporting power fed back onto the grid, there are increased requirements on the measurement accuracy at the output of the inverter as well.

Features
  • High bandwidth, low noise analog outputs – up to 120 kHz
  • High galvanic isolation – up to 3 kV dielectric withstand strength
  • High dV/dt immunity due to integrated shield in flip-chip devices
  • Low resistance on the primary conductor – 0.65 mΩ ~ 1 mΩ
  • Dedicated fault pin available on selected devices

Featured Products: ACS710 | ACS716 | ACS722 | ACS723 | ACS726

ACS710 - 5 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation

Allegro ACS710

Benefits

  • Small footprint package suitable for space-constrained applications
  • 1 mΩ primary conductor resistance for low power loss
  • High isolation voltage, suitable for line-powered applications
  • User-adjustable Overcurrent Fault level
  • 3 to 5.5 V, single-supply operation
  • Ratiometric output from supply voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS710 Bidirectional ±12 to 75 3000 3.3 ~ 5 120 K SOIC-16

ACS716 - 3.3 V, 120 kHz current sensor IC w/ dedicated fault pin, 3 kV isolation

Allegro ACS716

Benefits

  • Small footprint package suitable for space-constrained applications
  • 1 mΩ primary conductor resistance for low power loss
  • High isolation voltage, suitable for line-powered applications
  • User-adjustable Overcurrent Fault level
  • 3 to 3.6 V, single-supply operation
  • Factory trimmed sensitivity and quiescent output voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS716 Bidirectional ±12 to 75 3000 3.3 120 K SOIC-16

ACS722 - 3.3 V, 80 kHz current sensor IC w/ digital temperature compensation

Allegro ACS722

Benefits

  • 0.65 mΩ primary conductor resistance for low power loss and high inrush current withstand capability
  • 3 to 3.6 V, single supply operation
  • Output voltage proportional to AC or DC current
  • Nearly-zero magnetic hysteresis
  • Ratiometric output from supply voltage
  • Small footprint, low-profile SOIC8 package suitable for space-constrained applications
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS722 Bidirectional & Unidirectional ±5 to 40 2400 3.3 80 L SOIC-8

ACS723 - 5 V, 80 kHz current sensor IC w/ digital temperature compensation

Allegro ACS723

Benefits

  • Pin-selectable band width: 80 kHz for high bandwidth applications or 20 kHz for low noise performance.
  • 0.65 mΩ primary conductor resistance for low power loss and high inrush current withstand capability
  • Small footprint, low-profile SOIC8 package suitable for space-constrained applications
  • 4.5 to 5.5 V, single-supply operation
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS723 Bidirectional & Unidirectional 0~10 to 0~40 2400 5 80 L SOIC-8

ACS726 - Differential output current sensor IC w/ digital temperature compensation

Allegro ACS726

Benefits

  • Fully differential architecture for improved immunity to offset drift and common-mode noise
  • 1.1 mΩ primary conductor resistance for low power loss and high inrush current withstanding capability
  • Small footprint, low-profile QSOP24 package suitable for space-constrained applications
  • 3 to 3.6 V, single-supply operation
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS726 Bidirectional ±20, ±40 2100 3.3 120 L QSOP-24

Power Amplifiers

Allegro Power Amplifiers

Whether you are designing a base station or a handheld radio, being able to properly control the power amplifier in your radio is key to balancing power output versus performance.

Drain bias current is a key parameter to monitor in many output stages, and Allegro offers several current sensor ICs that are well suited to this task.

Features
  • Space saving, surface-mount packages – QFN and SOIC-8
  • Integrated low resistance primary conductor for low power loss – 0.6 mΩ~1.2 mΩ
  • 3.3 V or 5 V single-supply operation
  • Resistor-like transfer function for easy integration

Featured Products: ACS711 | ACS712

ACS711 - 100 kHz current sensor IC in QFN or SOIC package

Allegro ACS711

Benefits

  • Economical low- and high-side current sensing
  • Output voltage proportional to AC or DC currents
  • Low-noise analog signal path
  • Small footprint, low-profile SOIC8 and QFN packages
  • Integrated electrostatic shield for output stability
  • No external sense resistor required; single-package solution
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS711 Bidirectional ±12.5 to 32 <100 VDC 3.3 ~ 5 100 E, K QFN-12
SOIC-8

ACS712 - 80 kHz current sensor IC in SOIC package

Allegro ACS712

Benefits

  • Low-noise analog signal path
  • 5 µs output rise time in response to step input current
  • Total output error 1.5% at TA = 25°C
  • Small footprint, low-profile SOIC8 package
  • 1.2 mΩ internal conductor resistance
  • Extremely stable output offset voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS712 Bidirectional ±5 to 30 2100 5 80 E SOIC-8

Servers

Allegro Servers

Allegro offers several current sensing solutions for use in server power management. The integrated current conductor in these ICs reduces I2R losses in the power path.

Some ICs include I2C communications interfaces and dedicated fault output pins for easy system integration.

Features
  • Low resistance primary conductor for low power losses – 0.1 mΩ ~ 0.5 mΩ
  • Allegro’s latest digital temperature compensation circuitry
  • I2C interface for easy system integration
  • Dedicated fault output for fast response to overcurrent events

Featured Products: ACS764 | ACS770

ACS764 - 0.5 mΩ current sensor IC w/ I2C interface

Allegro ACS764

Benefits

  • High accuracy: typical error <2% over operating temperature range
  • Fast response digital fault output with programmable level through I2C bus interface
  • User-selectable decimation averaging of current output; up to 256 samples
  • 16 programmable I2C addresses
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS764 Unidirectional 0~16, 0~32 <100 VDC 3.3 2 X QSOP-24

ACS770 - 0.1 mΩ current sensor IC for up to 200 A

Allegro ACS770

Benefits

  • 4.1 µs output rise time in response to step input current
  • Small package size, with easy mounting capability
  • Monolithic Hall IC for high reliability
  • Ultra-low power loss: 100 µΩ internal conductor resistance
  • Output voltage proportional to AC or DC currents
  • Extremely stable output offset voltage
Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS770 Bidirectional & Unidirectional ±50 to 200 4800 5 120 E, K & L CB

Selection Guide

0 to 50 A Integrated Current Sensor ICs

Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS709 Bidirectional ±12 to 75 2100 3.3 ~ 5 120 L QSOP-24
ACS710 Bidirectional ±12 to 75 3000 3.3 ~ 5 120 K SOIC-16
ACS711 Bidirectional ±12.5 to 32 <100 VDC 3.3 ~ 5 100 E, K QFN-12
SOIC-8
ACS712 Bidirectional ±5 to 30 2100 5 80 E SOIC-8
ACS713 Unidirectional 0~20, 0~30 2100 5 80 E SOIC-8
ACS714 Bidirectional ±5 to 50 2100 5 80 E, L SOIC-8
ACS715 Unidirectional 0~20, 0~30 2100 5 80 E, L SOIC-8
ACS716 Bidirectional ±12 to 75 3000 3.3 120 K SOIC-16
ACS717 Bidirectional ±10 to 20 4800 3.3 40 K SOIC-16
ACS718 Bidirectional ±10 to 20 4800 6 40 K SOIC-16
ACS722 Bidirectional & Unidirectional ±5 to 40 2400 3.3 80 L SOIC-8
ACS723 Bidirectional & Unidirectional 0~10 to 0~40 2400 5 80 L SOIC-8
ACS724 Unidirectional 10 to 30
±10 to 30
2400 5 120 L SOIC-8
ACS725 Unidirectional 10
±20 to 40
2400 3.3 120 L SOIC-8
ACS726 Bidirectional ±20, ±40 2100 3.3 120 L QSOP-24
ACS764 Unidirectional 0~16, 0~32 <100 VDC 3.3 2 X QSOP-24

50 to 200 A Current Sensor ICs

Part Number Type Measurement Range (A) Isolation Voltage (VRMS) Supply Voltage Bandwidth (kHz) Temp Ranges Packages
ACS758 Bidirectional & Unidirectional ±50 to 200 4800 5 120 E, K & L CB
ACS759 Bidirectional & Unidirectional ±50 to 200 4800 3.3 120 E, K & L CB
ACS770 Bidirectional & Unidirectional ±50 to 200 4800 5 120 E, K & L CB

SIP Package 0 to >1000 A Current Sensor ICs

Part Number Supply Voltage Quiescent Output (V) Typical Sensitivity (mV/G) Output Bandwidth (kHz) Temp Ranges Packages
A1363 4.5 to 5.5 Typ 50% VCC 0.6~14, customer programmable 120 L KT, LU
A1366 4.5 to 5.5 Typ 50% VCC 1, 2, 5, & 10, factory programmed 120 L KT, LU

Temperature range codes: S = -20°C to 85°C, E = -40°C to 85°C, K = -40°C to 125°C, L = -40°C to 150°C, X = -20°C to 125°C

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