P r o d u c t I n n o v a t i o n F r o m

PA84 • PA84A • PA84S

PA84U

1

PA84, PA84A, PA84S

FEATURES

• HIGH SLEW RATE — 200V/µs

• FAST SETTLING TIME — .1% in 1µs (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

overvoltages 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 sup-

ply 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 semiconduc-

tor 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 warranty.

Please see “General Operating Considerations”.

EXTERNAL CONNECTION

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 100KΩ.

PHASE COMPENSATION

GAIN

1

10

100

1000

10nF

500pF

50pF

none

200Ω

2KΩ

20KΩ

none

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 combination

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

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

*

*

*

*

*

*

8-PIN TO-3

PACKAGE STYLE CE

Power Operational Amplifiers

PA84 • PA84A • PA84S

P r o d u c t

I n n o v a t i o n

F r o m

Copyright © Cirrus Logic, Inc. 2009

(All Rights Reserved)

http://www.cirrus.com

MAY 2009

APEX − PA84UREVP