Apex Microtechnology's PA85 is a high-voltage, high-power bandwidth MOSFET operational amplifier designed for output currents up to 200 mA. Output voltages can swing up to ±215 V with a dual supply and up to +440 V with a single supply. The safe operating area (SOA) has no second-breakdown limitations and can be observed with all types of loads by choosing an appropriate current limiting resistor. High accuracy is achieved with a cascade input circuit configuration. All internal biasing is referenced to a bootstrapped Zener-MOSFET current source. As a result, the PA85 features an unprecedented supply range and excellent supply rejection.

The MOSFET output stage is biased on for linear operation. External compensation provides user flexibility. This hybrid circuit utilizes thick film (cermet) resistors, ceramic capacitors, and silicon semiconductor chips to maximize reliability, minimize size, and provide top performance. Ultrasonically bonded aluminum wires provide reliable interconnections at all operating temperatures. The 8-pin TO-3 package is hermetically sealed and electrically isolated.