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MOTOR, VALVE AND ACTUATOR CONTROL
MAGNETIC DEFLECTION CIRCUITS UP TO 10A
POWER TRANSDUCERS UP TO 100kHz
TEMPERATURE CONTROL UP TO 360W
PROGRAMMABLE POWER SUPPLIES UP TO 90V
AUDIO AMPLIFIERS UP TO 120W RMS
POWER RATING
Not all vendors use the same method to rate the power
handling capability of a Power Op Amp. APEX rates the
internal dissipation, which is consistent with rating methods
used by transistor manufacturers and gives conservative
results. Rating delivered power is highly application depen-
dent and therefore can be misleading. For example, the 125W
internal dissipation rating of the PA12 could be expressed as
an output rating of 250W for audio (sine wave) or as 440W if
using a single ended DC load. Please note that all vendors rate
maximum power using an infinite heatsink.
DESCRIPTION
The PA12 is a state of the art high voltage, very high output
current operational amplifier designed to drive resistive, induc-
tive and capacitive loads. For optimum linearity, especially at
low levels, the output stage is biased for class A/B operation
using a thermistor compensated base-emitter voltage multi-
plier circuit. The safe operating area (SOA) can be observed
for all operating conditions by selection of user program-
mable current limiting resistors. For continuous operation
under load, a heatsink of proper rating is recommended.
This hybrid integrated circuit utilizes thick film (cermet)
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 isolation washers voids the warranty.
THERMAL STABILITY
APEX has eliminated the tendency of class A/B output
stages toward thermal runaway and thus has vastly increased
amplifier reliability. This feature, not found in most other Power
Op Amps, was pioneered by APEX in 1981 using thermistors
which assure a negative temperature coefficient in the quies-
cent current. The reliability benefits of this added circuitry far
outweigh the slight increase in component count.
EXTERNAL CONNECTIONS
R
CL+
+V
S
3
CL+
2
1
OUT
OUTPUT
TOP VIEW
EQUIVALENT SCHEMATIC
3
Q2A
D1
Q1
Q3
1
7
Q4
Q5
8
4
A1
5
C1
6
Q6A
Q6B
Q2B
2
+IN 4
鈥揑N
5
6
鈥揤
S
7
F.O.
8
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R
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APEX MICROTECHNOLOGY CORPORATION
鈥?TELEPHONE (520) 690-8600 鈥?FAX (520) 888-3329 鈥?ORDERS (520) 690-8601 鈥?EMAIL prodlit@apexmicrotech.com
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