PA83 • PA83A
High Voltage Power Operational Amplifiers
RoHS
COMPLIANT
FEATURES
• Low Bias Current, Low Noise — FET Input
• Fully Protected Input — Up to ±150V
• Wide Supply Range — ±15V to ±150V
APPLICATIONS
• High Voltage Instrumentation
• Electrostatic Transducers & Deflection
• Programmable Power Supplies up to 290V
• Analog Simulators
DESCRIPTION
The PA83 is a high voltage operational amplifier designed for output voltage swings up to ±145V with a
dual (±) supply or 290V with a single supply. Its input stage is protected against transient and steady state
overvoltages up to and including the supply rails. High accuracy is achieved with a cascode input circuit con‐
figuration. All internal biasing is referenced to a zener diode fed by a FET constant current source. As a result,
the PA83 features an unprecedented supply range and excellent supply rejection. The output stage is biased
in the class A/B mode for linear operation. Internal phase compensation assures stability at all gain settings
without need for external components. Fixed current limits protect these amplifiers against shorts to com‐
mon at supply voltages up to 120V. For operation into inductive loads, two external flyback pulse protection
diodes are recommended. However, a heatsink may be necessary to maintain the proper case temperature
under normal operating conditions.
This hybrid circuit utilizes beryllia (BeO) substrates, thick (cermet) film 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 thermal isolation washers
and/or improper mounting torque voids product warranty. Please see Application Note 1 “General Operating
Considerations.”
Figure 1: Equivalent Schematic
4
2
3
Q1
Q5
C2
Q8
C5 C4
5 Q12A
Q13
Q14
6 Q15
C1
D1
Q2
Q3
Q4
C3
Q9
Q10
Q12B
Q11
Q6
Q7
1
Q17
Q16
C6
7
D2
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© Apex Microtechnology Inc.
All rights reserved
Dec 2015
PA83U Rev Y
