Description
The HCPL-7840 isolation amplifer family was 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 HCPL-7840. A differential output voltage is created on the other side of the HCPL-7840 optical isolation barrier. This differential output voltage is proportional to the motor current and can be converted to a single-ended signal by using an op-amp as shown in the recommended application circuit. Since common-mode voltage swings of several hundred volts in tens of nanoseconds are common in modern switching inverter motor drives, the HCPL-7840 was designed to ignore very high common mode transient slew rates (of at least 10 kV/μs).

FEATUREs
• 15 kV/μs common-mode rejection at VCM = 1000 V
• Compact, auto-insertable standard 8-pin DIP package
• 0.00025 V/V/°C gain drift vs. temperature
• 0.3 mV input offset voltage
• 100 kHz bandwidth
• 0.004% nonlinearity
• Worldwide safety approval:
    UL 1577 (3750 Vrms/1 min.)
    and CSA, IEC/EN/DIN EN 60747-5-2
• Advanced Sigma-Delta (∑-Δ) A/D converter technology
• Fully differential circuit topology
• 0.8 μm CMOS IC technology

APPLICATIONs
• Motor phase and rail current sensing
• Inverter current sensing
• Switched mode power supply signal isolation
• General purpose current sensing and monitoring
• General purpose analog signal isolation