APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com

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FEATURES

• HIGH VOLTAGE OPERATION — ±150V (PA82J)

• HIGH OUTPUT CURRENT — ±30mA (PA81J)

• LOW BIAS CURRENT, LOW NOISE — FET Input

APPLICATIONS

• HIGH IMPEDANCE BUFFERS UP TO ±140V

• ELECTROSTATIC TRANSDUCER & DEFLECTION

• PROGRAMMABLE POWER SUPPLIES TO ±145V

• BIOCHEMISTRY STIMULATORS

• COMPUTER TO VACUUM TUBE INTERFACE

DESCRIPTION

The PA80 series of high voltage operation amplifiers provides

an extremely wide range of supply capability with two over-

lapping products. High accuracy is achieved with a cascode

input circuit configuration. All internal biasing is referenced

to a zener diode. As a result, these models offer outstanding

common mode and power supply rejection. The output stage

operates in the class A/B mode for best linearity. Internal phase

compensation assures stability at all gain settings without

external components. Fixed internal current limits protect

these amplifiers against a short circuit to common at most

supply voltages. For sustained high energy flyback, external

fast recovery diodes should be used. However, a heatsink

may be necessary to maintain the proper case temperature

under normal operating conditions.

This hybrid circuit utilizes thick film resistors, ceramic

capacitors and silicon semiconductors to maximize reliabil-

ity, minimize size and give top performance. Ultrasonically

bonded aluminum wires provide reliable interconnections

at all operating temperatures. The 8-pin TO-3 package (see

Package Outlines) is hermetically sealed and isolated from

the internal circuits. The use of compressible thermal washers

voids the warranty.

EXTERNAL CONNECTIONS

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TYPICAL APPLICATION

The PA81 and 70K ohm resistor form a current to voltage

converter, accepting ±1mA from a 12 bit current output digital

to analog converter. The power op amp contribution to the er-

ror budget is insignificant. At a case temperature of 70°C, the

combination of voltage offset and bias errors amounts to less

than 31ppm of full scale range. Incorporation of the optional

offset trim can further reduce these errors to under 9ppm.

EQUIVALENT SCHEMATIC

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8-PIN TO-3

PACKAGE STYLE CE