ACPL-C870/A/B Optically Isolated Voltage Sensors Broadcom ACPL-C870/ACPL-C87A/ACPL-C87B Optically Isolated Voltage Sensors are optical isolation amplifiers designed specifically for voltage sensing. The 2V input range and high 1GΩ input impedance makes these Broadcom devices well suited for isolated voltage sensing requirements in electronic power converters applications, including motor drives and renewable energy systems.