Precision Optically Isolated Voltage Sensor

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The ACPL-C87B/C87A/C870 voltage sensors are optical isolation amplifiers designed specifically for voltage sensing. Its 2V input range and high 1GΩ input impedance, makes it well suited for isolated voltage sensing requirements in electronic power converters applications including motor drives and renewable energy systems. In a typical voltage sensing implementation, a resistive voltage divider is used to scale the DC-link voltage to suit the input range of the voltage sensor. A differential output voltage that is proportional to the input voltage is created on the other side of the optical isolation barrier.

For general applications, the ACPL-C87A (±1% gain tolerance) and the ACPL-C870 (±3% gain tolerance) are recommended. For high precision requirements, the ACPL-C87B (±0.5% gain tolerance) can be used. The ACPL-C87B/C87A/C870 optical isolation amplifiers family operates from a single 5V supply and provides excellent linearity. An active-high shutdown pin is available which reduces the Idd1 current to only 15 uA, making them suitable for battery-powered and other power-sensitive applications.

The high common-mode transient immunity (15kV/us) of the ACPL-C87B/C87A/C870 provides the precision and stability needed to accurately monitor DC-link voltage in high noise environments. Combined with superior optical coupling technology, the ACPL-C87B/C87A/C870 implements sigma-delta modulation, chopper stabilized amplifiers, and differential outputs to provide unequaled isolation-mode noise rejection, low offset, high gain accuracy and stability. This performance is delivered in a compact, auto-insertable Stretched SO-8 (SSO-8) package that meets worldwide regulatory safety standards.


  • 0.5% High Gain Accuracy (ACPL-C87B only)
  • Unity Gain 1V/V
  • -35 ppm/°C Low Gain Drift
  • -0.3 mV Input Offset Voltage
  • 0.1% Excellent Non-Linearity Max
  • Active High Shutdown Pin
  • 100 kHz Wide Bandwidth
  • 3 V to 5.5 V Wide Supply Range for Output Side
  • –40°C to +105°C Operating Temperature Range
  • Advanced Sigma-Delta A/D Modulation Technology
  • 15 kV/µs Common-Mode Transient Immunity
  • Compact, Auto-Insertable Stretched SO-8 Package
  • Safety and Regulatory Approvals (pending):
    • IEC/EN/DIN EN 60747-5-5: 1230 Vpeak working insulation voltage
    • UL 1577: 5000 Vrms/1min double protection rating
    • CSA: Component Acceptance Notice #5


  • Isolated Voltage Sensing in AC and Servo Motor Drives
  • Isolated DC-Bus Voltage Sensing in Solar Inverters,
  • Wind Turbine Inverters
  • Isolated Sensor Interfaces
  • Signal Isolation in Data Acquisition Systems
  • General Purpose Voltage Isolation

Lifecycle Status


Substance Compliance

  • RoHS6
    Fully Compliant
Specification Value
Lifecycle Active
Distrib. Inventory Yes
RoHS6 Compliant Y
Product Type Miniature Isolation Amplifier
Package Stretched SO8
Operating Temperature Deg C -40 to +105
Gain Error at 25 Deg C (%) Max ±0.5
VDD2 (V) 3 - 5.5
CMR (min.) (V/µs) 15000.0
Vcm (V) 1000.0
UL Insulation Rating Viso (VRMS) 5000.0
IEC Maximum Working Insulation Voltage Viorm (VPEAK) 1414.0
IEC Highest Allowable Overvoltage Viotm (VPEAK) 8000
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