APEX MICROTECHNOLOGY CORPORATION
TELEPHONE (520) 690-8600 FAX (520) 888-3329 ORDERS (520) 690-8601 EMAIL prodlit@apexmicrotech.com
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 pro-
vides an extremely wide range of supply capability with two
overlapping 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 ca-
pacitors and silicon semiconductors to maximize reliability,
minimize size and give top performance. Ultrasonically bonded
aluminum wires provide reliable interconnections at all operat-
ing 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
TOP VIEW
1
2
3
4
5
6
7
8
–V
S
+IN
–IN
BAL
N.C.
OUTPUT
BAL
+V
S
NOTE: Input offset trimpot optional.
Recommended value of 100K .
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
error 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
+75V
–
75V
70K
PA81J
HIGH VOLTAGE PROGRAMMABLE POWER SUPPLY
±1mA
D/A
.47
.47
±70V
HTTP://WWW.APEXMICROTECH.COM (800) 546-APEX (800) 546-2739
M I C R O T E C H N O L O G Y
HIGH VOLTAGE POWER OPERATIONAL AMPLIFIERS
PA81J PA82J SERIES
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
C2
C3
Q11
Q6
Q7