ETC OPA541

®
OPA541
High Power Monolithic
OPERATIONAL AMPLIFIER
FEATURES
APPLICATIONS
● POWER SUPPLIES TO ±40V
● MOTOR DRIVER
● OUTPUT CURRENT TO 10A PEAK
● PROGRAMMABLE CURRENT LIMIT
● SERVO AMPLIFIER
● SYNCHRO EXCITATION
● AUDIO AMPLIFIER
● INDUSTRY-STANDARD PIN OUT
● FET INPUT
● TO-3 AND LOW-COST POWER PLASTIC
PACKAGES
● PROGRAMMABLE POWER SUPPLY
DESCRIPTION
The OPA541 is a power operational amplifier capable
of operation from power supplies up to ±40V and
delivering continuous output currents up to 5A. Internal current limit circuitry can be user-programmed
with a single external resistor, protecting the amplifier
and load from fault conditions. The OPA541 is fabricated using a proprietary bipolar/FET process.
Pinout is compatible with popular hybrid power amplifiers such as the OPA511, OPA512 and the 3573.
The OPA541 uses a single current-limit resistor to set
both the positive and negative current limits. Applications currently using hybrid power amplifiers requiring two current-limit resistors need not be modified.
The OPA541 is available in an 11-pin power plastic
package and an industry-standard 8-pin TO-3 hermetic package. The power plastic package has a copper-lead frame to maximize heat transfer. The TO-3
package is isolated from all circuitry, allowing it to be
mounted directly to a heat sink without special insulators.
+VS
–In
+In
Current
Sense
R CL
Output
Drive
VO
External
–VS
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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
®
PDS-737H
1
SBOS153
OPA541
SPECIFICATIONS
ELECTRICAL
At TC= +25°C and VS = ±35VDC, unless otherwise noted.
OPA541AM/AP
PARAMETER
CONDITIONS
INPUT OFFSET VOLTAGE
VOS
vs Temperature
vs Supply Voltage
vs Power
MIN
Specified Temperature Range
VS = ±10V to ±VMAX
INPUT BIAS CURRENT
IB
INPUT OFFSET CURRENT
IOS
MAX
TYP
MAX
UNITS
±2
±20
±2.5
±20
±10
±40
±10
±60
±0.1
±15
✻
✻
±1
±30
✻
✻
mV
µV/°C
µV/V
µV/W
4
50
✻
✻
pA
±1
±30
5
✻
✻
✻
pA
nA
Specified Temperature Range
INPUT CHARACTERISTICS
Common-Mode Voltage Range
Common-Mode Rejection
Input Capacitance
Input Impedance, DC
GAIN CHARACTERISTICS
Open Loop Gain at 10Hz
Gain-Bandwidth Product
OUTPUT
Voltage Swing
±(|VS| – 6)
95
±(|VS| – 3)
113
5
1
✻
✻
✻
✻
✻
✻
V
dB
pF
TΩ
RL = 6Ω
90
97
1.6
✻
✻
✻
dB
MHz
IO = 5A, Continuous
IO = 2A
IO = 0.5A
±(|VS| – 5.5)
±(|VS| – 4.5)
±(|VS| – 4)
9
±(|VS| – 4.5)
±(|VS| – 3.6)
±(|VS| – 3.2)
10
✻
✻
✻
✻
✻
✻
✻
✻
V
V
V
A
6
45
10
55
2
✻
✻
✻
✻
✻
V/µs
kHz
µs
nF
RL = 8Ω, VO = 20Vrms
2V Step
Specified Temperature Range, G = 1
Specified Temperature Range, G >10
Specified Temperature Range, RL = 8Ω
3.3
POWER SUPPLY
Power Supply Voltage, ±VS
Current, Quiescent
Specified Temperature Range
±10
THERMAL RESISTANCE
θJC (Junction-to-Case)(2)
θJC(2)
θJA (Junction-to-Ambient)
OPA541AP (Plastic)
AC Output f > 60Hz
DC Output
No Heat Sink
Phase Margin
TEMPERATURE RANGE
TCASE
MIN
Specified Temperature Range
VCM = (|±VS| – 6V)
Current, Peak
AC PERFORMANCE
Slew Rate
Power Bandwidth
Settling Time to 0.1%
Capacitive Load
OPA541BM/SM
TYP
✻
✻
SOA(1)
✻
40
±30
20
±35
25
✻
±35
✻
Degrees
±40
✻
°C/W
°C/W
°C/W
°C/W
2.5
3
40
40
AM, BM, AP
SM
–25
V
mA
+85
✻
–55
✻
+125
°C
°C
✻ Specification same as OPA541AM/AP.
NOTE: (1) SOA is the Safe Operating Area shown in Figure 1. (2) Plastic package may require insulator which typically adds 1°C/W.
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.
®
OPA541
2
CONNECTION DIAGRAMS
Top View
Plastic Package
TO–3
Tab at –VS
NC
+VS
3
+In
–In
2
1
Current
Sense
4
RCL
5
2
VO
8
6
–VS
1
Output
Drive
7
4
6
–In
3
5
+In
8
NC
7
–VS
9
11
NC
Output
Drive
NC
10
Current
Sense
RCL
+VS
VO
ABSOLUTE MAXIMUM RATINGS
ORDERING INFORMATION
Supply Voltage, +VS to –VS ............................................................... 80V
Output Current ............................................................................. see SOA
Power Dissipation, Internal(1) ........................................................... 125W
Input Voltage: Differential .................................................................... ±VS
Common-mode ............................................................. ±VS
Temperature: Pin solder, 10s ........................................................ +300°C
Junction(1) ............................................................... +150°C
Temperature Range:
AM, BM SM
Storage .................................................................... –65°C to +150°C
Operating (case) ...................................................... –55°C to +125°C
AP
Storage ...................................................................... –40°C to +85°C
Operating (case) ........................................................ –25°C to +85°C
PRODUCT
PACKAGE
TEMPERATURE
RANGE
OPA541AP
OPA541AM
OPA541BM
OPA541SM
Power Plastic
TO-3
TO-3
TO-3
–25°C to +85°C
–25°C to +85°C
–25°C to +85°C
–55°C to +125°C
CONTINUOUS
CURRENT
5A
5A
5A
5A
at
at
at
at
25°C
25°C
25°C
25°C
PACKAGE INFORMATION
NOTE: (1) Long term operation at the maximum junction temperature will
result in reduced product life. Derate internal power dissipation to achieve
high MTTF.
PRODUCT
PACKAGE
PACKAGE DRAWING
NUMBER(1)
OPA541AP
OPA541AM
OPA541BM
OPA541SM
Power Plastic
TO-3
TO-3
TO-3
242
030
030
030
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
ELECTROSTATIC
DISCHARGE SENSITIVITY
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.
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.
®
3
OPA541
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±35VDC, unless otherwise noted.
INPUT BIAS CURRENT
vs TEMPERATURE
OPEN-LOOP GAIN AND PHASE
vs FREQUENCY
100
Voltage Gain (dB)
Input Bias Current (nA)
0
–45
–90
90
10
1
0.1
0.01
Z L = 2k Ω
Phase
70
–135
–180
Z L = 3.3nF
50
Gain
30
Z L = 2k Ω
10
Z L = 3.3nF
–10
0.001
–25
0
25
50
75
100
1
125
10
100
NORMALIZED QUIESCENT CURRENT
vs TOTAL POWER SUPPLY VOLTAGE
100k
1M
10M
6
1.2
5
1.1
|±VS | – |VOUT | (V)
Normalized IQ
10k
OUTPUT VOLTAGE SWING
vs OUTPUT CURRENT
1.3
TC = –25°C
1
TC = +25°C
0.9
0.8
TC = +125°C
0.7
(+VS ) – VO
4
|–VS | – |VO |
3
2
1
0.6
0
20
30
40
50
60
70
80
90
0
1
2
3
4
5
6
7
8
+V S + |–VS | (V)
IOUT (A)
VOLTAGE NOISE DENSITY
vs FREQUENCY
TOTAL HARMONIC DISTORTION + NOISE
vs FREQUENCY
1k
9
10
10
1
THD + Noise (%)
Voltage Noise Density (nV/√Hz)
1k
Frequency (Hz)
Temperature (°C)
100
PO = 100mW
0.1
PO = 5W
PO = 50W
A V = –5
0.01
10
0.001
1
10
100
1k
10k
10
100k
®
OPA541
100
1k
Frequency (Hz)
Frequency (Hz)
4
10k
100k
Phase (Degrees)
110
TYPICAL PERFORMANCE CURVES
(CONT)
At TA = +25°C, VS = ±35VDC, unless otherwise noted.
CURRENT LIMIT vs RESISTANCE LIMIT
vs TEMPERATURE
CURRENT LIMIT
vs RESISTANCE LIMIT
10
10
Power Plastic
Power Plastic at –25°C
Power Plastic at +85°C
TO-3
ILIMIT (A)
ILIMIT (A)
TO-3 at –25°C
TO-3 at +85°C
1
1
NOTE: These are averaged values.
–I OUT is typically 10% higher.
+I OUT is typically 10% lower.
NOTE: These are averaged values.
–I OUT is typically 10% higher.
+I OUT is typically 10% lower.
0.1
0.01
0.1
1
0.1
0.01
10
0.1
1
R CL (Ω )
R CL (Ω )
COMMON-MODE REJECTION
vs FREQUENCY
DYNAMIC RESPONSE
10
120
Voltage (2V/division)
110
CMRR (dB)
100
90
80
70
60
50
10
100
1k
10k
100k
Time (1µs/division)
1M
Frequency (Hz)
®
5
OPA541
INSTALLATION
INSTRUCTIONS
Sinusoidal outputs create dissipation according to rms load
current. For the same RCL, AC peaks would still be limited
to 5A, but rms current would be 3.5A, and a current limiting
resistor with a lower power rating could be used. Some
applications (such as voice amplification) are assured of
signals with much lower duty cycles, allowing a current
resistor with a low power rating. Wire-wound resistors may
be used for RCL. Some wire-wound resistors, however, have
excessive inductance and may cause loop-stability problems. Be sure to evaluate circuit performance with resistor
type planned for production to assure proper circuit operation.
POWER SUPPLIES
The OPA541 is specified for operation from power supplies
up to ±40V. It can also be operated from unbalanced power
supplies or a single power supply, as long as the total power
supply voltage does not exceed 80V. The power supplies
should be bypassed with low series impedance capacitors
such as ceramic or tantalum. These should be located as near
as practical to the amplifier’s power supply pins. Good
power amplifier circuit layout is, in general, like good high
frequency layout. Consider the path of large power supply
and output currents. Avoid routing these connections near
low-level input circuitry to avoid waveform distortion and
oscillations.
HEAT SINKING
Power amplifiers are rated by case temperature, not ambient
temperature as with signal op amps. Sufficient heat sinking
must be provided to keep the case temperature within rated
limits for the maximum ambient temperature and power
dissipation. The thermal resistance of the heat sink required
may be calculated by:
CURRENT LIMIT
Internal current limit circuitry is controlled by a single
external resistor, RCL. Output load current flows through this
external resistor. The current limit is activated when the
voltage across this resistor is approximately a base-emitter
turn-on voltage. The value of the current limit resistor is
approximately:
0.809
– 0.057
(AM, BM, SM)
RCL =
| ILIM|
(AP)
RCL =
θ HS =
0.813
– 0.02
| ILIM|
No insulating hardware is required when using the TO-3
package. Since mica and other similar insulators typically
add approximately 0.7°C/W thermal resistance, their elimination significantly improves thermal performance. See BurrBrown Application Bulletin AB-038 for further details on
heat sinking. On the power plastic package, the metal tab is
connected to –VS , and appropriate actions should be taken
when mounting on a heat sink or chassis.
The current limit value decreases with increasing temperature due to the temperature coefficient of a base-emitter
junction voltage. Similarly, the current limit value increases
at low temperatures. Current limit versus resistor value and
temperature effects are shown in the Typical Performance
Curves. Approximate values for RCL at other temperatures
may be calculated by adjusting RCL as follows:
SAFE OPERATING AREA
The safe operating area (SOA) plot provides comprehensive
information on the power handling abilities of the OPA541.
It shows the allowable output current as a function of the
voltage across the conducting output transistor (see Figure
1). This voltage is equal to the power supply voltage minus
the output voltage. For example, as the amplifier output
swings near the positive power supply voltage, the voltage
across the output transistor decreases and the device can
safely provide large output currents demanded by the load.
–2mV
x (T – 25)
| ILIM|
The adjustable current limit can be set to provide protection
from short circuits. The safe short-circuit current depends on
power supply voltage. See the discussion on Safe Operating
Area to determine the proper current limit value.
Since the full load current flows through RCL, it must be
selected for sufficient power dissipation. For a 5A current
limit on the TO-3 package, the formula yields an RCL of
0.105Ω (0.143Ω on the power plastic package due to different internal resistances). A continuous 5A through 0.105Ω
would require an RCL that can dissipate 2.625W.
®
OPA541
PD (max)
Commercially available heat sinks often specify their thermal resistance. These ratings are often suspect, however,
since they depend greatly on the mounting environment and
air flow conditions. Actual thermal performance should be
verified by measurement of case temperature under the
required load and environmental conditions.
Because of the internal structure of the OPA541, the actual
current limit depends on whether current is positive or
negative. The above RCL gives an average value. For a given
RCL, +IOUT will actually be limited at about 10% below the
expected level, while –IOUT will be limited about 10% above
the expected level.
∆RCL =
TCASE – TAMBIENT
6
APPLICATIONS CIRCUITS
SAFE OPERATING AREA
10
+VS
TC = +25°C
TC = +85°C
10µF
|IO | (A)
0.1µF
TC = +125°C
“M” Package only
1
D1
OPA541
AP, AM
BM, SM
D2
Inductive or
EMF-Generating
Load
L
0.1
1
10
100
10µF
0.1µF
|V S – VOUT | (V)
D1 – D2 : IN4003
–VS
FIGURE 1. Safe Operating Area.
Short circuit protection requires evaluation of SOA. When
the amplifier output is shorted to ground, the full power
supply voltage is impressed across the conducting output
transistor. The current limit must be set to a value which is
safe for the power supply voltage used. For instance, with VS
±35V, a short to ground would force 35V across the conducting power transistor. A current limit of 1.8A would be safe.
FIGURE 2. Clamping Output for EMF-Generating Loads.
R2
20pF 100k Ω
R1
10kΩ
A V = –R2 /R1
= –10
0.1Ω
VIN
Reactive, or EMF-generating, loads such as DC motors can
present difficult SOA requirements. With a purely reactive
load, output voltage and load current are 90° out of phase.
Thus, peak output current occurs when the output voltage is
zero and the voltage across the conducting transistor is equal
to the full power supply voltage. See Burr-Brown Application Bulletin AB-039 for further information on evaluating
SOA.
OPA541
Master
10kΩ
L
20pF
OPA541
Slave
REPLACING HYBRID POWER AMPLIFIERS
The OPA541 can be used in applications currently using
various hybrid power amplifiers, including the OPA501,
OPA511, OPA512, and 3573. Of course, the application
must be evaluated to assure that the output capability and
other performance attributes of the OPA541 meet the necessary requirement. These hybrid power amplifiers use two
current limit resistors to independently set the positive and
negative current limit value. Since the OPA541 uses only
one current limit resistor to set both the positive and negative
current limit, only one resistor (see Figure 4) need be
installed. If installed, the resistor connected to pin 2 (TO-3
package) is superfluous, but it does no harm.
0.1Ω
FIGURE 3. Isolating Capacitive Loads.
RCL +
2
2
OPA501
8
Not Required
1
RCL –
OPA541
1
8
RCL
Pin 2 is “open” on OPA541.
FIGURE 4. Replacing OPA501 with OPA541.
Because one resistor carries the current previously carried
by two, the resistor may require a higher power rating.
Minor adjustments may be required in the resistor value to
achieve the same current limit value. Often, however, the
change in current limit value when changing models is small
compared to its variation over temperature. Many applications can use the same current limit resistor.
®
7
OPA541
+60V
+35V
0.1µF
0.1µF
R2
10kΩ
25kΩ
0–2mA
30pF
DAC80-CBI-I
VO
OPA541
VO
OPA541
0.5Ω
VIN
*
0.3Ω
0.1µF
R1
2.5kΩ
0.1µF
* Protects DAC
During Slewing
A V = 1 + R 2 /R 1 = 5
–35V
FIGURE 5. Paralleled Operation, Extended SOA.
–8V
FIGURE 6. Programmable Voltage Source.
+35V
+15V
1µF
1µF
100pF
Digital Word
Input
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
23
18
0.5Ω
OPA541
MSB
VOUT =
–30V to
+30V
1µF
–35V
21
DAC702
+15V
±1mA
FB
10kΩ*
17
1µF
10kΩ
LSB
19
20
7
6
OPA27
1µF
2
* TCR
Tracking
Resistors
3
4
–15V
5kΩ *
1µF
–15V
FIGURE 7. 16-Bit Programmable Voltage Source.
®
OPA541
8
0–50V
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright  2000, Texas Instruments Incorporated