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

EXTERNAL CONNECTION

FEATURES

• HIGH SLEW RATE — 200V/

µs

• FAST SETTLING TIME — .1% in 1

µs (PA84S)

• FULLY PROTECTED INPUT — Up to

±150v

• LOW BIAS CURRENT, LOW NOISE — FET Input

• WIDE SUPPLY RANGE —

±15V to ±150V

APPLICATIONS

• HIGH VOLTAGE INSTRUMENTATION

• ELECTROSTATIC TRANSDUCERS & DEFLECTION

• PROGRAMMABLE POWER SUPPLIES UP TO 290V

• ANALOG SIMULATORS

DESCRIPTION

The PA84 is a high voltage operational amplifier designed for

output voltage swings up to

±145V with a dual supply or 290V

with a single supply. Two versions are available. The new

PA84S, fast settling amplifier can absorb differential input over-

voltages up to

±50V while the established PA84 and PA84A can

handle differential input overvoltages of up to

±300V. Both

versions are protected against common mode transients and

overvoltages up to the supply rails. High accuracy is achieved

with a cascode input circuit configuration. All internal biasing is

referenced to a zener diode fed by a FET constant current

source. As a result, the PA84 features an unprecedented supply

range and excellent supply rejection. The output stage is biased-

on for linear operation. External phase compensation allows for

user flexibility in obtaining the maximum slew rate. Fixed current

limits protect these amplifiers against shorts to common at

supply voltages up to 150V. 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 integrated circuit utilizes a beryllia (BeO) sub-

strate, thick film resistors, ceramic capacitors and semicon-

ductor 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 will void the product war-

ranty. Please see “General Operating Considerations”.

TOP VIEW

1

2

3

4

5

6

7

8

+IN

–IN

BAL

COMP

OUT

BAL

NOTES:

1. Phase Compensation required

for safe operation.

2. Input offset trimpot optional.

Recommended value 100K

.

Ω

PHASE COMPENSATION

GAIN

1

10

100

1000

10nF

500pF

50pF

none

200

2K

20K

none

Ω

Ω

Ω

TYPICAL APPLICATION

The PA84 is ideally suited to driving ink jet control units

(often a piezo electric device) which require precise pulse

shape control to deposit crisp clear date or lot code information

on product containers. The external compensation network

has been optimized to match the gain setting of the circuit and

the complex impedance of the ink jet control unit. The combi-

nation of speed and high voltage capabilities of the PA84 form

ink droplets of uniform volume at high production rates to

enhance the value of the printer.

EQUIVALENT SCHEMATIC

+150V

–150V

100K

PA84

±10V

50K

INK JET

CONTROL

10K

DAC

......

......

......

4.7K

390pF

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(800) 546-APEX

(800) 546-2739

MICROTECHNOLOGY

POWER OPERATIONAL AMPLIFIERS

PA84 • PA84A • PA84S

2

7

4

3

5

6

1

Q1

Q2

D1

D2

Q15

Q12B

Q9

C4

Q8

Q13

Q4

Q3

C1

Q16

Q17

Q5

C5

Q12A

Q14

C6

Q10

Q6

Q7

Q11

8

*

*

*

*

*

*