HCPL-7800

The Agilent Technologies HCPL-7800 is an isolation amplifier family specifically designed for current sensing applications in electronic motor drives. It utilizes advanced Sigma-Delta (Σ−∆) A/D converter technology and a fully differential circuit topology to provide high accuracy, stability, and linearity even in noisy environments.

Key features include a common-mode rejection ratio (CMR) of 15 kV/µs at VCM = 1000 V, a bandwidth of 100 kHz, and low gain drift of 0.00025 V/V/°C. The device also boasts a low input offset voltage of 0.3 mV and nonlinearity of 0.004%.

In a typical implementation, motor currents are sensed through an external resistor, and the resulting voltage drop is measured by the HCPL-7800. A differential output voltage is generated across the optical isolation barrier, proportional to the motor current. This output can be converted to a single-ended signal using an op-amp.

The HCPL-7800 is housed in a compact, auto-insertable, standard 8-pin DIP package, meeting worldwide safety standards. It is suitable for motor phase and rail current sensing, inverter current sensing, switched-mode power supply signal isolation, and general-purpose analog signal isolation.