The HCPL-7840 isolation amplifi er family was designed for current sensing in electronic motor drives. In a typical implementation, motor currents fl ow through an external resistor and the resulting analog voltage drop is sensed by the HCPL-7840. A diff erential output voltage is created on the other side of the HCPL-7840 optical isolation barrier.This diff erential 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 commonmode transient slew rates (of at least 10 kV/μs).

The high CMR capability of the HCPL-7840 isolation amplifi er provides the precision and stability needed to accurately monitor
motor current in high noise motor control environ-ments, providing for smoother control(less "torque ripple") in various types of motor control applications.

The product can also be used for general analog signal isolation applications requiring high accuracy, stability,and linearity under similarly severe noise con-ditions. For general applications, we recommend the HCPL-7840 (gain
tolerance of ± 5%). The HCPL-7840 utilizes sigma delta(∑-Δ) analog-to-digital converter technology, chopper stabilized amplifi ers, and a fully diff erential circuit topology fabricated using Avago's 0.8 μm CMOS IC process.Together, these features deliver
unequaled isolationmode noise rejection, as well as excellent off set and gain accuracy and stability over time and temperature. This performance is delivered in a compact, auto-insertable,industry standard 8-pin DIP package that meets worldwide regulatory safety standards. (A gull-wing surface mount option #300 is also available).

? 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

? 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 off set 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 diff erential circuit topology
? 0.8 μm CMOS IC technology