PA74/76 • PA74A/76A
PA74-76U 1
PA74, PA76, PA74A, PA76A
Power Dual Operational Amplifiers
PA74/PA76 • PA74A/76A
COMMAND
INPUT
0/10V
AMB
R2
9K
R3
10K
R4
10K
R5
10K
R6
10K
R1
5K
1/2 PA74 1/2 PA74
+28V
+
_
+
_
+28V
FEATURES
• LOW COST
• WIDE COMMON MODE RANGE —
Includes negative supply
• WIDE SUPPLY VOLTAGE RANGE
Single supply: 5V to 40V
Split supplies: ±2.5V to ±20V
• HIGH EFFICIENCY — |Vs–2.2V| at 2.5A typ
• HIGH OUTPUT CURRENT — 3A
• LOW DISTORTION
APPLICATIONS
• HALF & FULL BRIDGE MOTOR DRIVERS
• AUDIO POWER AMPLIFIER
STEREO — 30W RMS per channel
BRIDGE — 60W RMS per package
• IDEAL FOR SINGLE SUPPLY SYSTEMS
5V — Peripherals, 12V — Automotive
28V — Avionic
DESCRIPTION
The amplier design consists of dual monolithic input and output
stages to achieve the desired input and output characteristics
of the PA74 and PA76. The input stage utilizes a dual power op
amp on a single chip monolithic that drives the output stages.
The output stages are congured in a non inverting unity gain
buffer conguration. The output stages of the amplier are also
compensated for stability. The PA74 and PA76 dual ampliers are
designed with both monolithic and hybrid technologies providing
a cost effective solution for applications requiring multiple ampli-
ers per board or bridge mode congurations. Both ampliers
are internally compensated but are not recommended for use
as unity gain followers.
This dual hybrid circuit utilizes a beryllia (BeO) substrate, thick
lm resistors, ceramic capacitors and monolithic ampliers to
maximize reliability and power handling capability, 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 isolation washers voids the
warranty.
EQUIVALENT SCHEMATIC ONE CHANNEL
TYPICAL APPLICATION
R1 and R2 set up amplier A in a non-inverting gain of 2.8.
Amp B is set up as a unity gain inverter driven from the output
of amp A. Note that amp B inverts signals about the reference
node, which is set at mid-supply (14V) by R5 and R6. When
the command input is 5V, the output of amp A is 14V. Since
this is equal to the reference node voltage, the output of amp
B is also 14V, resulting in 0V across the motor. Inputs more
positive than 5V result in motor current ow from left to right
(see Figure 1). Inputs less positive than 5V drive the motor in
the opposite direction.
The ampliers are especially well-suited for this application.
The extended common mode range allows command inputs
as low as 0V. Its superior output swing abilities let it drive
within 2V of supply at an output current of 2A. This means
that a command input that ranges from 0.714V to 9.286V will
drive a 24V motor from full scale CCW to full scale CW at up
to ±2A. A single power op amp with an output swing capability
of Vs –6 would require ±30V supplies and would be required to
swing 48V p-p at twice the speed to deliver an equivalent drive.
EXTERNAL CONNECTIONS
FIGURE 1: BIDIRECTIONAL
SPEED CONTROL FROM A
SINGLE SUPPLY.
8-PIN TO-3
PACKAGE STYLE CE
+VS
-IN
-VS
+IN
I BIAS
MONITOR
THERMAL
PROTECT
CURRENT
GAIN
CURRENT
GAIN
OUT
+VS
+IN,A
-IN,A
OUT,A
–VS
+IN,B
-IN,B
OUT,B
TOP
VIEW
1
23
4
5
6
7
8
A
B
–
+
–+
PA76
+VS
-IN,A
+IN,A
+IN,B
–IN,B
-VS
OUT,B
OUT,A
TOP
VIEW
1
23
4
5
6
7
8
B
–
+
A
–
+
PA74
Copyright © Apex Microtechnology, Inc. 2012
(All Rights Reserved)
www.apexanalog.com OCT 2012
PA74-76U REVH
2 PA74-76U
PA74/76 • PA74A/76A
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, total 5V to 40V
OUTPUT CURRENT SOA
POWER DISSIPATION, internal (per amplier) 36W
POWER DISSIPATION, internal (both ampliers) 60W
INPUT VOLTAGE, differential ±VS
INPUT VOLTAGE, common mode +VS, -VS–0.5V
JUNCTION TEMPERATURE, max1 150°C
TEMPERATURE, pin solder–10 sec max 350°C
TEMPERATURE RANGE, storage –65°C to 150°C
OPERATING TEMPERATURE RANGE, case –55°C to 125°C
SPECIFICATIONS
PA74/76 PA74A/PA76A
PARAMETER TEST CONDITIONS2 MIN TYP MAX MIN TYP MAX UNITS
INPUT
OFFSET VOLTAGE, initial 1.5 10 .5 7 mV
OFFSET VOLTAGE, vs. temperature Full temperature range 20 10 µV/°C
BIAS CURRENT, initial 100 500 * 250 nA
COMMON MODE RANGE Full temperature range –VS +VS–1.3 * * V
COMMON MODE REJECTION, DC Full temperature range 60 70 * * dB
POWER SUPPLY REJECTION Full temperature range 60 90 * * dB
CHANNEL SEPARATION IOUT = 1A, F = 1kHz 50 70 * * dB
INPUT NOISE VOLTAGE RS = 100Ω, f = 1 to 100KHz
GAIN
OPEN LOOP GAIN Full temperature range 89 100 * * * dB
GAIN BANDWIDTH PRODUCT AV = 40dB 0.9 1.4 * * MHz
POWER BANDWIDTH VO(P-P) = 28V 13.6 * kHz
OUTPUT
CURRENT, peak 2.5 3 A
SLEW RATE 0.5 1.4 * * V/µs
VOLTAGE SWING Full temp. range, IO = 100mA |VS| –1.1 |VS| –0.9 * * V
VOLTAGE SWING Full temp. range, IO = 1A |VS| –2.0 |VS| –1.7 * * V
VOLTAGE SWING IO = 2.5A (PA74, 76) |VS| –3.5 |VS| –2.9 * * V
VOLTAGE SWING IO = 3.0A (PA74A, PA76A) |VS| –4.0 |VS| –3.3 V
POWER SUPPLY
VOLTAGE, VSS3 30 40 * * * V
CURRENT, quiescent, total 18 40 * * mA
THERMAL
RESISTANCE, junction to case
DC, single amplier 3.2 3.5 * * °C/W
DC, both ampliers4 1.9 2.1 * * °C/W
AC, single amplier 2.4 2.6 * * °C/W
AC, both ampliers4 1.4 1.6 * * °C/W
RESISTANCE, junction to air 30 * * °C/W
TEMPERATURE RANGE, case Meets full range specications –25 85 –25 85 °C
NOTES: * The specication of PA74A/PA76A is identical to the specication for PA74/PA76 in applicable column to the left.
1. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF.
2. Unless otherwise noted, the following conditions apply: ±VS = ±15V, TC = 25°C.
3. +VS and –VS denote the positive and negative supply rail respectively. VSS denotes the total rail-to-rail supply voltage.
4. Rating applies when power dissipation is equal in the two ampliers.
The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or
subject to temperatures in excess of 850°C to avoid generating toxic fumes.
CAUTION
PA74/76 • PA74A/76A
PA74-76U 3
-80 1401006020-20
0.4
1.2
1.0
0.8
0.6
2.0
1.8
1.5
1.4
NORMALIZED QUIESCENT CURRENT, I
Q
(X)
CASE TEMPERATURE, TC (°C)
NORMALIZED QUIESCENT CURRENT
vs. CASE TEMPERATURE
NORMALIZED QUIESCENT CURRENT
vs. SUPPLY VOTAGE
NORMALIZED QUIESCENT CURRENT, I
Q
(X)
SUPPLY VOLTAGE, VS (V)
200 15105
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
OUTPUT VOLTAGE SWING
OUTPUT CURRENT, IO (A)
VOLTAGE DROP FROM SUPPLY, V
DROP
(V)
0.0 3.50.5 1.0 1.5 2.0 2.5 3.0
1.5
1.0
0.5
0.0
2.0
2.5
3.0
3.5
4.0
PULSE RESPONSE
TIME, t (s)
OUTPUT VOLTAGE, VO (V)
400 1.4K1.2K1.0K8006002000
-10
15
10
5
0
-5
-15
+VS = +15V
AV = +1
VIN = 10Vp
-VS = -15V
RL = 10Ω
fIN = 1KHz
PULSE RESPONSE
TIME, t (s)
OUTPUT VOLTAGE, VO (V)
20 7060504030100
-10
15
10
5
0
-5
-15
+VS = +15V
AV = +1
VIN = 10Vp
-VS = -15V
RL = 10Ω
fIN = 20KHz
0 40 80 120 160-40-80
1.0
0.9
0.8
0.7
0.6
1.1
1.2
1.3
NORMALIZED BIAS CURRENT, IB (X)
TEMPERATURE, (°C)
IB
FREQUENCY, f (Hz)
80
120
160
200
240
280
1K 10K 100K 1M 10M
PHASE, Ф (°)
PHASE vs. FREQUENCY
FREQUENCY, f (Hz)
60
40
20
0
-20
-40
1K 10K 100K 1M 10M
GAIN, A (dB)
VOLTAGE GAIN vs. FREQUENCY
80
VOS
NORMALIZED OFFSET VOLTAGE, V
OS
(X)
12080400-40
-4
8
4
0
TEMPERATURE, (°C)
4 PA74-76U
PA74/76 • PA74A/76A
GENERAL
Please read Application Note 1 "General Operating Consider-
ations" which covers stability, supplies, heatsinking, mounting,
SOA interpretation, and specication interpretation. Visit www.
apexanalog.com for design tools that help automate tasks such
as calculations for stability, internal power dissipation, heatsink
selection; Apex Microtechnology's complete Application Notes
library; Technical Seminar Workbook; and Evaluation Kits.
STABILITY CONSIDERATIONS
All monolithic power op amps use output stage topologies
that present special stability problems. This is primarily due to
non-complementary (both devices are NPN) output stages with
a mismatch in gain and phase response for different polarities
of output current. It is difficult for the opamp manufacturer to
optimize compensation for all operating conditions.
SAFE OPERATING AREA (SOA)
The SOA curves combine the effect of all limits for this power
op amp. For a given application, the direction and magnitude
of the output current should be calculated or measured and
checked against the SOA curves. This is simple for resistive
loads but more complex for reactive and EMF generating loads.
THERMAL CONSIDERATIONS
Thermal grease or a Apex Microtechnology TW03 thermal
washer, RCS = .1 to .2°C/W, is the only recommended interface
for the PA74/76. Internal power dissipation increases directly
with frequency therefore it is critical to sufficiently heat sink
the PA74 and PA76. Even unloaded the PA74 and PA76 can
dissipate up to 3 watts while running at higher frequencies.
SOA
TWO AMPLIFIERS LOADED
ONE AMPLIFIER
LOADED
1001.0 10
0.1
1.0
10
SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE, VS - VO (V)
OUTPUT CURRENT FROM +VS or -VS, (A)
DC, TC = 85°C
DC, TC = 25°C
PARALLEL CONFIGURATION CONSIDERATIONS
LOSSES
The PA74 and PA76 utilize a parallel conguration to achieve
the desired current output requirements. The parallel congura-
tion inherently creates internal losses due to circulating currents.
The circulating currents generate power losses through the
current sharing resistors when delivering current to the load.
SUPPLY CURRENT
The parallel conguration used in the PA74 and PA76 also
generates supply currents while high voltage sign waves are
seen at the output. Listed below are the supply currents expected
while running at a particular frequency and when VO ≈ 15Vpp,
note that the outputs are not loaded.
Frequency Supply Current
100Hz 18mA
1KHz 20mA
5KHz 32mA
10KHz 50mA
15KHz 75mA
SATURATION OPERATION
The parallel conguration used in the PA74 and PA76 is
sensitive to operation in the saturation region. The PA74 and
PA76 may exhibit large peak currents; this is mainly due to
thermal protection limitations.
0
10
20
30
40
50
60
70
POWER DERATING
0 25 50 75 100 125
TWO AMPLIFIERS LOADED
ONE AMPLIFIER LOADED
CASE TEMPERATURE, TC (°C)
INTERNAL POWER DISSIPATION, P (W)
PA74/76 • PA74A/76A
PA74-76U 5
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Apex Microtechnology, Apex and Apex Precision Power are trademarks of Apex Microtechnolgy, Inc. All other corporate names noted herein may be trademarks
of their respective holders.
Copyright © Apex Microtechnology, Inc. 2012
(All Rights Reserved)
www.apexanalog.com OCT 2012
PA74-76U REVH