ACPL-785J Isolation Amplifier with Short Circuit and Overload Detection

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The ACPL-785J isolation amplifier is designed for current sensing in electronic motor drives. In a typical implementation, motor currents flow through an external resistor and the resulting analog voltage drop is sensed by the ACPL-785J. A larger analog output voltage is created on the other side of the ACPL-785J’s optical isolation barrier. The output voltage is proportional to the motor current and can be connected directly to a single-supply A/D converter. A digital over-range output (/FAULT) and an analog rectified output (ABSVAL) are also provided.

The wire OR-able over-range output (/FAULT) is useful for quick detection of short circuit conditions on any of the motor phases. The wire-OR-able rectified output (ABSVAL), simplifies measure-ment of motor load since it performs polyphase rectification. Since the common-mode voltage swings several hundred volts in tens of nanoseconds in modern electronic motor drives, the ACPL-785J was designed to ignore very high common-mode transient slew rates (10 kV/μs).

±3% gain tolerance part (HCPL-788J) is also available


  • Output Voltage Directly Compatible with A/D Converters (0 V to VREF)
  • Fast (3 μs) Short Circuit Detection with Transient Fault Rejection
  • Absolute Value Signal Output for Overload Detection
  • 1 μV/°C Offset Change vs. Temperature
  • SO-16 Package
  • –40°C to +85°C Operating Temperature Range
  • 25 kV/μs Isolation Transient Immunity
  • Regulatory Approvals: UL, CSA, IEC/EN/DIN EN 60747-5-5 (1230 Vpeak Working Voltage)
  • Options:


  • Inverter Current Sensing
  • Switching Power Supply Signal Isolation
  • Industrial A/D Converter
  • Motor Phase and Rail Current Sensing
  • General Purpose Current Sensing and Monitoring

Lifecycle Status


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Substance Compliance

  • RoHS6
    Fully Compliant
Specification Value
Lifecycle Active
Distrib. Inventory Yes
RoHS6 Compliant Y
Product Type Miniature Isolation Amplifier
Package SO16
Operating Temperature Deg C -40 to +85
Gain Error at 25 Deg C (%) Max ±5
VDD2 (V) 4.5 - 5.5
CMR (min.) (V/µs) 25000.0
UL Insulation Rating Viso (VRMS) 5000.0
IEC Maximum Working Insulation Voltage Viorm (VPEAK) 1230.0
IEC Highest Allowable Overvoltage Viotm (VPEAK) 8000

Application Note6 i
Brochures1 i
Design Guide1 i
Options Data Sheet3 i
Product Change Notice (PCN)6 i
Regulatory Certificate2 i
Selection Guide2 i
White Papers2 i
FAQs1 i
Promotional Material1 i


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