PA88 Datasheet, PDF (1/5 Pages) Cirrus Logic – HIGH VOLTAGE POWER OPERATIONAL AMPLIFIERS

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PA88PA•8P8 A• P8A88A8A
High Voltage Power Operational Amplifiers
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 MOSFET
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 cur-
rent 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
Q1
Q6
– IN
5
Q10A
Q13
Q2
Q4
Q7
+ IN
4
Q10B
3
D1
+V_S
D19
Q8
Q9
COMP
CL
78
Q12
2
Q11
Q17
1
OUT
Q16
D2
Q18
–V_S
6
PATENTED
TYPICAL APPLICATION
8-pin TO-3
PACKAGE STYLE CE
R_F
+V_S
C_C
R _IN
PA88
PIEZO DRIVE
V _OUT
COMPUTER
FOCUS
COMMAND
VOLTAGE
–V _S
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
+Vs
3
CL R _CL
2
+IN ₄
TOP VIEW
1 OUT
PHASE COMPENSATION
GAIN
1
10
20
100
C_C
68pf
33pf
15pf
3.3pf
R_C
100W
100W
100W
—
–IN ⁵
6
7
–Vs
COMP
COMP
8
C_C
R_CL =
.7
I_LIM
R_C
C_C RATED FOR FULL
SUPPLY VOLTAGE
PA88_hU_{ttp://www.cirrus.com}
Copyright © Cirrus Logic, Inc. 2009
(All Rights Reserved)
MAY 2009₁
APEX − PA88UREVN