PA85 PA85A RoHS High Voltage Power Operational Amplifiers COMPLIANT FEATURES High Voltage 450V (225V) High Slew Rate 1000V/s High Output Current 200mA 500 kHz Power Bandwidth APPLICATIONS High Voltage Instrumentation Piezo Transducer Excitation Programmable Power Supplies up to 430V Electrostatic Transducers & Deflection DESCRIPTION The PA85 is a high voltage, high power bandwidth MOSFET operational amplifier designed for output cur- rents up to 200mA. Output voltages can swing up to 215V with a dual supply and up to +440V 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 cascode 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 give 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. The use of compressible isolation washers voids the warranty. Figure 1: Equivalent Schematic 9 6 4 4 4 4 4 &203 &/ 4 4 4 ,1 ,1 4 4 % 4 287 4 4 4 4 9 6 Apex Microtechnology Inc. Apr 2020 www.apexanalog.com All rights reserved PA85U Rev UPA85 PA85A TYPICAL CONNECTION Figure 2: Typical Connection 2 PA85U Rev U