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 — 450V (±225V)

• LOW QUIESCENT CURRENT — 2mA

• HIGH OUTPUT CURRENT — 100mA

• PROGRAMMABLE CURRENT LIMIT

• LOW BIAS CURRENT — FET Input

APPLICATIONS

• PIEZOELECTRIC POSITIONING

• HIGH VOLTAGE INSTRUMENTATION

• ELECTROSTATIC TRANSDUCERS

• PROGRAMMABLE POWER SUPPLIES UP TO 440V

DESCRIPTION

The PA88 is a high voltage, low quiescent current MOS-

FET operational amplifier designed for output currents up to

100mA. Output voltages can swing up to ±215V with a dual

supply and up to +440 volts 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 PA88 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 beryllia (BeO) substrates, thick

film resistors, ceramic capacitors and semiconductor chips to

maximize reliability, minimize size and give top performance.

Ultrasonically bonded aluminum wires provide reliable inter-

connections 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 will void the product warranty. Please see

“General Operating Considerations”.

EQUIVALENT SCHEMATIC

TYPICAL APPLICATION

LOW POWER, PIEZOELECTRIC POSITIONING

Piezo positioning may be applied to the focusing of

segmented mirror systems. The composite mirror may be

composed of hundreds of elements, each requiring focusing

under computer control. In such complex systems the PA88’s

advantage of low quiescent power consumption reduces

the costs of power supplies and cooling, while providing the

interface between the computer and the high voltage drive to

the piezo positioners.

EXTERNAL CONNECTIONS

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8-PIN TO-3

PACKAGE STYLE CE