Burr-Brown OPA502BM High current, high power operational amplifier Datasheet

®
OPA502
High Current, High Power
OPERATIONAL AMPLIFIER
FEATURES
APPLICATIONS
● HIGH OUTPUT CURRENT: 10A
● MOTOR DRIVER
● WIDE POWER SUPPLY VOLTAGE:
±10V to ±45V
● USER-SET CURRENT LIMIT
● SERVO AMPLIFIER
● PROGRAMMABLE POWER SUPPLY
● ACTUATOR DRIVER
● SLEW RATE: 10V/µs
● FET INPUT: IB = 200pA max
● CLASS A/B OUTPUT STAGE
● AUDIO AMPLIFIER
● TEST EQUIPMENT
● QUIESCENT CURRENT: 25mA max
● HERMETIC TO-3 PACKAGE —
ISOLATED CASE
V+
3
DESCRIPTION
The OPA502 is a high output current operational
amplifier designed to drive a wide range of resistive
and reactive loads. Its complementary class A/B
output stage provides superior performance in
applications requiring freedom from crossover distortion. Resistor-programmable current limits provide
protection for both the amplifier and the load during
abnormal operating conditions. An adjustable foldover
current limit can also be used to protect against
potentially damaging conditions.
5
280Ω
2
+Output
Drive
1
Current
Sense
4
20kΩ
Bias
Circuit
20kΩ
The OPA502 employs a custom monolithic op amp/
driver circuit and rugged complementary output
transistors, providing excellent DC and dynamic
performance.
The industry-standard 8-pin TO-3 package is electrically isolated from all circuitry. This allows the
OPA502 to be mounted directly to a heat sink without
cumbersome insulating hardware which degrade
thermal performance. The OPA502 is available in
–40°C to +85°C temperature range.
280Ω
6
7
8
RFO
– Output
Drive
V–
International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111
Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
®
© 1992 Burr-Brown Corporation
PDS-1166B
1
Printed in U.S.A. March, 1998
OPA502
SPECIFICATIONS
TCASE = +25°C, VS = ±40V, unless otherwise noted.
OPA502BM
PARAMETER
CONDITION
OFFSET VOLTAGE
Input Offset Voltage
vs Temperature
vs Power Supply
Specified Temp. Range
VS = ±10V to ±45V
MIN
TYP
MAX
UNITS
±5
74
±0.5
±5
92
mV
µV/°C
dB
200
pA
pA
INPUT BIAS CURRENT(1)
Input Bias Current
Input Offset Current
VCM = 0V
VCM = 0V
12
±3
NOISE
Input Voltage Noise
Noise Density,
Current Noise Density,
f = 1kHz
f = 1kHz
25
3
nV/√Hz
fA/√Hz
(V+) –4
(V–) +4
106
V
V
dB
1012 || 5
1012 || 4
Ω || pF
Ω || pF
103
dB
2.0
10
See Typical Curves
0.06
MHz
V/µs
INPUT VOLTAGE RANGE
Common-Mode Input Range, Positive
Negative
Common-Mode Rejection
Linear Operation
Linear Operation
VCM = ±35V
(V+) –5
(V–) +5
74
INPUT IMPEDANCE
Differential
Common-Mode
OPEN-LOOP GAIN
Open-Loop Voltage Gain
FREQUENCY RESPONSE
Gain-Bandwidth Product
Slew Rate
Full-Power Bandwidth
Total Harmonic Distortion
VO = ±34V, RL = 6Ω
92
G = +10, RL = 50Ω
68Vp-p, RL = 6Ω
5
G = +3, f = 20kHz
VO = 20V, RL = 8Ω
Capacitive Load
%
See Figure 6
OUTPUT
Voltage Output, Positive
Negative
Positive
Negative
Current Output
Short Circuit Current
POWER SUPPLY
Specified Operating Voltage
Operating Voltage Range
Quiescent Current
TEMPERATURE RANGE
Specification
Storage
Thermal Resistance, θJC
θJA
IO = 10A
IO = 10A
IO = 1A
IO = 1A
(V+) –6
(V–) +6
±10
IO = 0
(V+)–3.5
(V–) +3.6
(V+) –2.5
(V–) +3.1
See SOA Curves
Resistor Programmed
±40
±20
–40
–55
DC
AC f ≥ 50Hz
No Heat Sink
1.25
0.8
30
V
V
V
V
±45
±25
+85
+125
1.4
0.9
V
V
mA
°C
°C
°C/W
°C/W
°C/W
NOTE: (1) High-speed test at TJ = 25°C.
ABSOLUTE MAXIMUM RATINGS(1)
PACKAGE/ORDERING INFORMATION
Supply Voltage, V+ to V– ..................................................................... 90V
Output Current .................................................................. See SOA Curve
Input Voltage .............................................................. (V–) –1V to (V+)+1V
Case Temperature, Operating ......................................................... 150°C
Junction Temperature ...................................................................... 200°C
PRODUCT
PACKAGE
PACKAGE
DRAWING
NUMBER(1)
OPA502BM
8-Pin TO-3
030
TEMPERATURE
RANGE
–40°C to +85°C
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
NOTE: (1) Stresses above these ratings may cause permanent damage.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
®
OPA502
2
ELECTROSTATIC
DISCHARGE SENSITIVITY
PIN CONFIGURATION
Top View
TO-3
V+
2
3
+Output
Drive
1
+In
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
+
RCL
Current
Sense
VO
4
ESD damage can range from subtle performance degradation
to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric
changes could cause the device not to meet its published
specifications.
–
–In
RCL
5
8
6
–Output
Drive
7
V–
RFO
TYPICAL PERFORMANCE CURVES
TCASE = +25°C, VS = ±40V, unless otherwise noted.
CURRENT LIMIT vs TEMPERATURE
CURRENT LIMIT vs LIMIT RESISTOR
2.4
0.24
2.2
0.22
RCL = 5.0Ω
1
ICL (A)
ICL (A)
2.0
–ICL
+ICL
0.20
1.8
0.18
1.6
0.16
RCL = 0.5Ω
1.4
0.14
NOTE: These are average values.
–ICL is typically 8% higher.
+ICL is typically 8% lower.
1.2
0.01
0.10
1
0.10
–50
10
–25
0
OPEN-LOOP GAIN AND PHASE vs FREQUENCY
50
75
100
125
SUPPLY CURRENT vs TEMPERATURE
100
–45
80
–90
–135
RL = 50Ω
40
–180
30
Supply Current (mA)
0
Phase (degrees)
120
60
25
Case Temperature (°C)
RCL (Ω)
Voltage Gain (dB)
0.12
1.0
0.10
ICL (A)
10
20
VS = ±10 to ±45V
RL = 4Ω
20
0
10
10
100
1k
10k
100k
1M
10M
–50
Frequency (Hz)
–25
0
25
50
75
100
125
Case Temperature (°C)
®
3
OPA502
TYPICAL PERFORMANCE CURVES
(CONT)
TCASE = +25°C, VS = ±40V, unless otherwise noted.
INPUT BIAS CURRENT vs
INPUT COMMON-MODE VOLTAGE
INPUT BIAS AND OFFSET CURRENTS
vs TEMPERATURE
2.2
1.8
1nA
Normalized (IB)
Input Bias and Offset Current (pA)
10nA
IB
100
IOS
10
1.4
1.0
0.6
0.2
1
–50
–25
0
25
50
75
100
–40
125
–30
–20
–10
10
0
VOLTAGE NOISE DENSITY vs FREQUENCY
40
2.8
RL = 10kΩ
2.4
2.0
1k
GBWP (MHz)
Voltage Noise (nV/ Hz)
30
GAIN BANDWIDTH PRODUCT vs TEMPERATURE
10k
100
RL = 50Ω
1.6
G = +10
1.2
0.8
RL = 4Ω
0.4
10
0
1
10
100
10k
1k
100k
–50
–25
Frequency (Hz)
0
50
25
75
100
125
Case Temperature (°C)
POWER SUPPLY REJECTION vs FREQUENCY
COMMON-MODE REJECTION vs FREQUENCY
120
120
100
100
CMRR (dB)
PSRR (dB)
20
Common-Mode Voltage (V)
Case Temperature (°C)
80
60
40
80
60
40
20
20
1
10
100
1k
10k
100k
1M
1
Frequency (Hz)
100
1k
Frequency (Hz)
®
OPA502
10
4
10k
100k
1M
TYPICAL PERFORMANCE CURVES
(CONT)
TCASE = +25°C, VS = ±40V, unless otherwise noted.
FULL POWER RESPONSE
SLEW RATE vs TEMPERATURE
35
14
30
Output Voltage (VPK)
Slew Rate (V/µs)
12
–SR
10
8
G = +10
VO = 34VPK
RL = 6Ω
6
+SR
25
20
15
G = +10
RL = 8Ω
THD < 2%
10
5
0
4
–50
–25
0
25
50
75
100
10k
125
100k
TOTAL HARMONIC DISTORTION AND NOISE
vs FREQUENCY
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
1.000
5
0.100
4
PO = 100mW
PO = 5W
|±VS| – |VOUT| (V)
G = +3
RL = 8Ω
Measurement
BW = 80kHz
PO = 50W
0.010
(+VS) – VO
3
|–VS| – |VO|
2
1
0.001
0
20
100
10k 20k
1k
0
1
2
3
Frequency (Hz)
4
5
6
7
8
9
10
IOUT (A)
OUTPUT VOLTAGE SWING vs TEMPERATURE
5
IO = +10A
4
|±VS| – |VO| (V)
THD + N (%)
1M
Frequency (Hz)
Case Temperature (°C)
IO = +1A
3
2
IO = –10A
IO = –1A
1
0
–50
–25
0
25
50
75
100
125
Case Temperature (°C)
®
5
OPA502
TYPICAL PERFORMANCE CURVES
(CONT)
TCASE = +25°C, VS = ±40V, unless otherwise noted.
SMALL SIGNAL RESPONSE
G = +3, CL = 1000pF
LARGE SIGNAL RESPONSE
G = +3, RL = 4Ω
APPLICATIONS INFORMATION
+40V
Power supply terminals should be bypassed with low series
impedance capacitors such as ceramic or tantalum close to the
device pins. Power supply wiring should have low series
impedance and inductance. Figure 1 indicates the high current
connections in bold lines.
2µF
R1
R2
+
RCL
Current limit is set with two external resistors—one for
positive output current and one for negative output current
(see Figure 1). For conventional current limit, independent of
output voltage, pin 7 should be left open (see “Foldback
Current Limit”). Limiting occurs when the output current
causes sufficient voltage drop across RCL to turn on the
respective current limit transistor. The limit current decreases
at high temperature (see typical performance curve “Current
Limit vs Temperature).
5
4
VIN
OPA502
1
8
R2
R1
VO
–
RCL
6
2µF
Load
0.1µF
NOTE: Bold lines indicate
high current paths.
–40V
The current limit resistors can be chosen from a variety of
types. Most common wire-wound types are satisfactory, although some physically large types may have excessive
inductance which can cause problems. You should test your
circuits with the exact resistor type planned for production
use.
G=1+
3
2
Figure 1 also shows nominal current limit produced by standard resistor values. See also the typical performance curve
“Current Limit vs Limit Resistance”. The output current must
flow through this resistor, so its power rating must be chosen
accordingly. The table in Figure 1 shows the power dissipation of the current limit resistor during continuous current
limit (room temperature). Connections from the current limit
resistors to the device pins can typically add 0.02Ω to 0.05Ω
to the effective value of RCL. This significantly affects the
current limit value for high output currents.
RCL
(Ω)
ICL
at 25°C
(A)
Power
Dissipation1
of RCL (W)
10
5
2
1
0.68
0.5
0.3
0.2
0.15
0.1
0.11
0.19
0.44
0.78
1.22
1.65
2.73
4.0
5.4
8.1
0.12
0.18
0.39
0.61
1.0
1.4
2.2
3.2
4.4
6.6
NOTE 1: Power dissipation during continuous
current limit at TCASE = +25°C.
FIGURE 1. Basic Circuit Connections.
You can set different current limits for positive and negative
current. Resistors are chosen with the same table of values in
Figure 1.
tor. The power dissipated by the output transistor is equal to
the product of the output current and the voltage across the
conducting transistor, VCE. The Safe Operating Area (SOA
curve, Figure 2) shows the permissible range of voltage and
current.
SAFE OPERATING AREA
Stress on the output transistors is determined by the output
current and the voltage across the conducting output transis®
OPA502
0.1µF
6
circuit can be set to allow high output current when VCE is low
(high output voltage). Output current limits at a lower value
under the more stressful condition when VCE is high, (output
voltage is low).
The safe output current decreases as VCE increases. Output
short-circuits are a very demanding case for SOA. A shortcircuit to ground forces the full power supply voltage (V+ or
V–) across the conducting transistor. With VS = ±40V the
current limit must be set for 3A (25°C) to be safe for continuous short-circuit to ground. For further insight on SOA,
consult AB-039.
The behavior of this voltage-dependant current limit is described by the following equation.
0.81 +
ILIMIT =
SAFE OPERATING AREA
10
t=
t=
TC = +25°C
m
0.5
s
1m
5.0
TC = +85°C
where: VO is the output voltage measured with respect to
ground.
s
t=
s
IO (A)
RFO is the resistor connected from pin 7 to ground (in
k ohms).
5m
2.0
0.28 VO
RFO + 20
+ 0.03
RCL
1.0
RCL is the current limit resistor (in ohms).
0.5
Ther mal Limitation
(TJ = 200°C)
0.2
The foldover limit circuitry can be set to allow large voltage
and current to resistive loads, yet limit output current to a safe
value with an output short circuit.
Second Breakdown
Limited
0.1
1
2
5
10
20
50
100
Reactive or EMF-generating loads can produce unexpected
behavior with the foldover circuit driven into limiting. With a
reactive load, peak output current occurs at low or zero output
voltage. Compared to a resistive load, a reactive load with the
same total impedance will be more likely to activate the
foldover limit circuitry.
|VS – VOUT| (V)
FIGURE 2. Safe Operating Area (SOA).
UNBALANCED POWER SUPPLIES
Some applications do not require equal positive and negative
output voltage swing. The power supply voltages of the
OPA502 do not need to be equal. Figure 3 shows a circuit
designed for a positive output voltage and current. The –5V
power supply voltage assures that the inputs of the OPA502
are operated within their linear common-mode range. The V+
power supply could range from 15V to 85V. The total voltage
(V– to V+) can range from 20V to 90V.
V+
Fast Recovery Diode
5A, 100V
MR821
OPA502
55V
at 0.5A
MR821
9kΩ
1kΩ
V–
2Ω
VIN
FIGURE 4. Diode Protection of Output.
0 to 50V
VO
OPA502
22Ω
0 to 5V
Inductive or
EMF-Generating
Load
OUTPUT PROTECTION
The output stage of the OPA502 is protected by internal diode
clamps to the power supply terminals. These internal diodes
are similar to common silicon rectifier types and may not be
fast enough for adequate protection. For loads that can deliver
large reverse kickback current (greater than 5A) to the output,
external fast-recovery clamp diodes are recommended
(Figure 4). For these diodes (internal or external) to provide
the intended protection, the power supplies must provide a
low impedance to a reverse current.
0.5A
RL
–5V
at 50mA
FIGURE 3. Unbalanced Power Supplies.
FOLDOVER CURRENT LIMIT
By connecting a resistor from pin 7 to ground, you can make
the limit current vary with output voltage. The foldover limit
®
7
OPA502
MOUNTING AND HEAT SINKING
Most applications require a heat sink to assure that the maximum junction temperature is not exceeded. The heat sink
required depends on the power dissipated and on ambient
conditions. Consult Application Bulletin AB-038 for information on determining heat sink requirements.
COMPENSATION AND STABILITY
Capacitance at the inverting input causes a high frequency
pole in the feedback path. This reduces phase margin, causing
pulse response ringing, and in severe cases, oscillations. A
low value feedback capacitor can reduce or eliminate this
effect by maintaining a constant feedback factor at high
frequency (see Figure 5).
The case of the OPA502 is isolated from all circuitry and can
be fastened directly to a heat sink. This eliminates cumbersome insulating hardware that degrades thermal performance.
Consult Application Bulletin AB-037 for proper mounting
techniques and procedures for TO-3 power products.
Depending on the load conditions, precautions may be required when using the OPA502 in low gains. Gains less than
+3V/V or –2V/V may cause oscillations, particularly with
capacitive loads. Figure 6 shows several circuits for low gain
and capacitive loads.
SOCKET
Large value feedback capacitors used to limit the closed-loop
bandwidth or form an integrator may also produce instability
because the closed-loop gain approaches unity at high frequency.
C2 =
A mating socket, 0804MC is available for the OPA502 and
can be purchased from Burr-Brown. Although not required,
this socket makes interchanging parts easy, especially during
design and testing.
R1
C
R2 IN
R2
R1
OPA502
CIN
CIN = Input capacitance, package and wiring ≈ 20pF
FIGURE 5. Compensating Input Capacitance.
®
OPA502
8
10kΩ
20kΩ
VIN
470pF
10kΩ
OPA502
CL ≤ 0.01µF
G = –2
10kΩ
20kΩ
VIN
4µH
10Ω
OPA502
CL ≤ 0.1µF
G = –2
Prevents
phase-inversion
in G = 1 circuits
IN4148
20kΩ
OPA502
VIN
10kΩ
470pF
CL ≤ 2200pF
G = +1
FIGURE 6. Compensation Circuits.
®
9
OPA502
20kΩ
10kΩ
10pF
G = +21
47pF
10Ω
0.1Ω
OPA502
VIN
VS = ±15V
4.7kΩ
100kΩ
4µH
0.1Ω
OPA27
VS = ±40V
1kΩ
4Ω
THD at 50W
0.02% at 20kHz
0.002% at 1kHz
FIGURE 7. Low Distortion Composite Amplifier.
+35V
+35V
10kΩ
10kΩ
10kΩ
20kΩ
0.2Ω
0.2Ω
3nF
20Ω
OPA502
OPA502
0.2Ω
VIN
1kΩ
0.2Ω
Load
±10V
120Vp-p
(±60V)
G = +3
G = –1
–35V
–35V
FIGURE 8. Bridge Drive Circuit.
+30V
10V
REF102
+30V
20kΩ
+5V
20pF
8-bit
data port
(8 + 4 bits)
40kΩ
0-1mA
0.1Ω
10kΩ
10kΩ
OPA602
4.7kΩ
DAC7801
12-bit
M-DAC
OPA502
0.1Ω
470pF
–30V
FIGURE 9. Digitally Programmable Power Supply.
®
OPA502
10
VO
±20V
at 5A
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