POWER OPERATIONAL AMPLIFIERS
PA84 • PA84A • PA84S
M I C R O T E C H N O L O G Y
HTTP://WWW.APEXMICROTECH.COM
(800) 546-APEX
(800) 546-2739
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
100K 50K
+150V
4.7K
±10V
10K
390pF
PA84
INK JET
CONTROL
–150V
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”.
DAC
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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
4
2
C1
D1
3
Q3
Q1
Q5
Q2
Q4
8
Q6
Q8
C5
*
C4
Q12A
Q9
Q10
Q12B
Q11
1
Q7
EXTERNAL CONNECTION
PHASE COMPENSATION
BAL
3
4
2
5
*
*
C6
*
7
Q13
*
Q14
*
Q15
D2
Q16
Q17
+V
S
1
GAIN
OUT
C
C
1
10
100
1000
C
C
10nF
500pF
50pF
none
R
C
200
Ω
2K
Ω
20K
Ω
none
6
BAL
5
TOP VIEW
R
C
6
8
7
–IN
+IN
–V
S
COMP
NOTES:
1. Phase Compensation required
for safe operation.
2. Input offset trimpot optional.
Recommended value 100K
Ω
.
APEX MICROTECHNOLOGY CORPORATION
• TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
CIRRUS [ CIRRUS LOGIC ]
