PA74/76 • PA74/76A
M I C R O T E C H N O L O G Y
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
8-PIN TO-3
PACKAGE STYLE CE
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
FIGURE 1: BIDIRECTIONAL
SPEED CONTROL FROM A
SINGLE SUPPLY.
DESCRIPTION
The amplifier 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 configured in a non inverting unity gain
buffer configuration. The output stages of the amplifier are also
compensated for stability. The PA74 and PA76 dual amplifiers are
designed with both monolithic and hybrid technologies providing
a cost effective solution for applications requiring multiple ampli-
fiers per board or bridge mode configurations. Both amplifiers
are internally compensated but are not recommended for use
as unity gain followers.
This dual hybrid circuit utilizes a beryllia (BeO) substrate, thick
film resistors, ceramic capacitors and monolithic amplifiers 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.
TYPICAL APPLICATION
R1 and R2 set up amplifier 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 flow from left to right
(see Figure 1). Inputs less positive than 5V drive the motor in
the opposite direction.
The amplifiers 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.
EQUIVALENT SCHEMATIC
ONE CHANNEL
EXTERNAL CONNECTIONS
(TOp viEws)
PA74
PA76
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1
PA74/76 • PA74A/PA76A
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, total
OUTPUT CURRENT
POWER DISSIPATION, internal (per amplifier)
POWER DISSIPATION, internal (both amplifiers)
INPUT VOLTAGE, differential
INPUT VOLTAGE, common mode
JUNCTION TEMPERATURE, max
1
TEMPERATURE, pin solder–10 sec max
TEMPERATURE RANGE, storage
OPERATING TEMPERATURE RANGE, case
MIN
PA74/76
TYP
1.5
20
100
70
90
70
MAX
10
500
+V
S
–1.3
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
5V to 40V
SOA
36W
60W
±V
S
+V
S
, -V
S
–0.5V
150°C
300°C
–65°C to 150°C
–55°C to 125°C
PA74A/PA76A
MIN
TYP
MAX
.5
10
*
*
*
*
7
250
*
SPECIFICATIONS
PARAMETER
INPUT
OFFSET VOLTAGE, initial
OFFSET VOLTAGE, vs. temperature
BIAS CURRENT, initial
COMMON MODE RANGE
COMMON MODE REJECTION, DC
POWER SUPPLY REJECTION
CHANNEL SEPARATION
INPUT NOISE VOLTAGE
GAIN
OPEN LOOP GAIN
GAIN BANDWIDTH PRODUCT
POWER BANDWIDTH
OUTPUT
CURRENT, peak
SLEW RATE
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
POWER SUPPLY
VOLTAGE, VSS
3
CURRENT, quiescent, total
THERMAL
RESISTANCE, junction to case
DC, single amplifier
DC, both amplifiers
4
AC, single amplifier
AC, both amplifiers
4
RESISTANCE, junction to air
TEMPERATURE RANGE, case
TEST CONDITIONS
2
UNITS
mV
µV/°C
nA
V
dB
dB
dB
Full temperature range
Full temperature range
Full temperature range
Full temperature range
I
OUT
= 1A, F = 1kHz
R
S
= 100Ω, f = 1 to 100KHz
Full temperature range
A
V
= 40dB
V
O(P-P)
= 28V
–V
S
60
60
50
*
*
*
*
89
0.9
100
1.4
13.6
*
*
*
*
*
*
dB
MHz
kHz
A
V/µs
V
V
V
V
Full temp. range, I
O
= 100mA
Full temp. range, I
O
= 1A
I
O
= 2.5A (PA74, 76)
I
O
= 3.0A (PA74A, PA76A)
2.5
0.5
|V
S
| –1.1
|V
S
| –2.0
|V
S
| –3.5
1.4
|V
S
| –0.9
|V
S
| –1.7
|V
S
| –2.9
3
*
*
*
*
|V
S
| –4.0
40
40
*
*
*
*
*
|V
S
| –3.3
*
*
*
*
30
18
V
mA
Meets full range specifications
–25
3.2
1.9
2.4
1.4
30
3.5
2.1
2.6
1.6
85
–25
*
*
*
*
*
*
*
*
*
*
85
°C/W
°C/W
°C/W
°C/W
°C/W
°C
NOTES: * The specification of PA74A/PA76A is identical to the specification 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 amplifiers.
CAUTION
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.
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2
TYPICAL PERFORMANCE
GRAPHS
PA74/76 • PA74A/PA76A
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
3
PA74/76 • PA74A/PA76A
GENERAL
Please read Application Note 1 "General Operating Consider-
ations" which covers stability, supplies, heatsinking, mounting,
SOA interpretation, and specification interpretation. Visit www.
apexmicrotech.com for design tools that help automate tasks
such as calculations for stability, internal power dissipation,
heatsink selection; Apex's complete Application Notes library;
Technical Seminar Workbook; and Evaluation Kits.
OPERATING
CONSIDERATIONS
PARALLEL CONFIGURATION CONSIDERATIONS
LOSSES
The PA74 and PA76 utilize a parallel configuration to
achieve the desired current output requirements. The paral-
lel configuration 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.
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.
SUPPLY CURRENT
The parallel configuration 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
100Hz
1KHz
5KHz
10KHz
15KHz
Supply Current
18mA
20mA
32mA
50mA
75mA
SATURATION OPERATION
The parallel configuration 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.
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 an Apex 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.
This data sheet has been carefully checked and is believed to be
NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
APEX MICROTECHNOLOGY CORPORATION • 5980
reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifications are subject to change without notice.
4
PA74–76U REV D OCTOBER 2006 © 2006 Apex Microtechnology Corp.
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