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OPA549
High-Voltage, High-CurrentOPERATIONAL AMPLIFIER
DESCRIPTIONThe OPA549 is a low-cost, high-voltage/high-current
opera-tional amplifier ideal for driving a wide variety of loads.
Thislaser-trimmed monolithic integrated circuit provides
excellentlow-level signal accuracy and high output voltage and
current.The OPA549 operates from either single or dual supplies
fordesign flexibility. The input common-mode range extendsbelow the
negative supply.The OPA549 is internally protected against
over-temperatureconditions and current overloads. In addition, the
OPA549provides an accurate, user-selected current limit.
Unlikeother designs which use a power resistor in series with
theoutput current path, the OPA549 senses the load indirectly.This
allows the current limit to be adjusted from 0A to 10Awith a
resistor/potentiometer, or controlled digitally with avoltage-out
or current-out Digital-to-Analog Converter (DAC).The Enable/Status
(E/S) pin provides two functions. It can bemonitored to determine
if the device is in thermal shutdown,and it can be forced low to
disable the output stage andeffectively disconnect the load.The
OPA549 is available in an 11-lead power package. Itscopper tab
allows easy mounting to a heat sink for excellentthermal
performance. Operation is specified over the ex-tended industrial
temperature range, 40C to +85C.
FEATURES HIGH OUTPUT CURRENT:
8A Continuous10A Peak
WIDE POWER-SUPPLY RANGE:Single Supply: +8V to +60VDual Supply:
4V to 30V
WIDE OUTPUT VOLTAGE SWING FULLY PROTECTED:
Thermal ShutdownAdjustable Current Limit
OUTPUT DISABLE CONTROL THERMAL SHUTDOWN INDICATOR HIGH SLEW
RATE: 9V/s CONTROL REFERENCE PIN 11-LEAD POWER PACKAGE
APPLICATIONS VALVE, ACTUATOR DRIVERS SYNCHRO, SERVO DRIVERS
POWER SUPPLIES TEST EQUIPMENT TRANSDUCER EXCITATION AUDIO POWER
AMPLIFIERS
OPA549
V+
E/S
RCL
RCL sets the current limitvalue from 0A to 10A.(Very Low Power
Dissipation)
ILIMVO
V
Ref
ES PinForced Low: Output disabled.Indicates Low: Thermal
shutdown.
OPA549
OPA549
www.ti.com
PRODUCTION DATA information is current as of publication
date.Products conform to specifications per the terms of Texas
Instrumentsstandard warranty. Production processing does not
necessarily includetesting of all parameters.
Copyright 1999-2005, Texas Instruments Incorporated
Please be aware that an important notice concerning
availability, standard warranty, and use in critical applications
ofTexas Instruments semiconductor products and disclaimers thereto
appears at the end of this data sheet.
SBOS093E MARCH 1999 REVISED OCTOBER 2005
All trademarks are the property of their respective owners.
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OPA549SBOS093E
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Output Current ................................................
See SOA Curve (Figure 6)Supply Voltage, V+ to V
...................................................................
60VInput Voltage Range ....................................... (V)
0.5V to (V+) + 0.5VInput Shutdown Voltage
................................................... Ref 0.5 to
V+Operating Temperature
..................................................40C to
+125CStorage Temperature
.....................................................55C to
+125CJunction Temperature
......................................................................
150CLead Temperature (soldering, 10s)
................................................. 300CESD
Capability (Human Body Model)
............................................. 2000V
NOTE: (1) Stresses above these ratings may cause permanent
damage.Exposure to absolute maximum conditions for extended periods
may de-grade device reliability.
CONNECTION DIAGRAM
In
+In Ref ILIM
E/S
V+VO
1 3 5 7 9 11
2 4 6 8 10
V
Tab connected to V. Do not use to conduct current.
Connect both pins 1 and 2 to output.Connect both pins 5 and 7 to
V.Connect both pins 10 and 11 to V+.
ABSOLUTE MAXIMUM RATINGS(1)
For the most current package and ordering information, seethe
Package Option Addendum at the end of this datasheetor see the TI
website at www.ti.com.
PACKAGE/ORDERING INFORMATION
ELECTROSTATICDISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas
Instru-ments recommends that all integrated circuits be handled
withappropriate precautions. Failure to observe proper handlingand
installation procedures can cause damage.ESD damage can range from
subtle performance degradationto complete device failure. Precision
integrated circuits may bemore susceptible to damage because very
small parametricchanges could cause the device not to meet its
publishedspecifications.
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ELECTRICAL CHARACTERISTICSBoldface limits apply over the
specified temperature range, TA = 40C to +85C.At TCASE = +25C, VS =
30V, Ref = 0V, and E/S pin open, unless otherwise noted.
OPA549T, SPARAMETER CONDITION MIN TYP MAX UNITSOFFSET VOLTAGE
VOSInput Offset Voltage VCM = 0V, IO = 0 1 5 mVvs Temperature
dVOS/dT TCASE = 40C to +85C 20 V/Cvs Power Supply PSRR VS = 4V to
30V, Ref = V 25 100 V/V
INPUT BIAS CURRENT(1)Input Bias Current(2) IB VCM = 0V 100 500
nAvs Temperature TCASE = 40C to +85C 0.5 nA/C
Input Offset Current IOS VCM = 0V 5 50 nANOISEInput Voltage
Noise Density en f = 1kHz 70 nV/HzCurrent Noise Density in f = 1kHz
1 pA/HzINPUT VOLTAGE RANGECommon-Mode Voltage Range: Positive VCM
Linear Operation (V+) 3 (V+) 2.3 V
Negative VCM Linear Operation (V) 0.1 (V) 0.2 VCommon-Mode
Rejection Ratio CMRR VCM = (V) 0.1V to (V+) 3V 80 95 dBINPUT
IMPEDANCEDifferential 107 || 6 || pFCommon-Mode 109 || 4 ||
pFOPEN-LOOP GAINOpen-Loop Voltage Gain AOL VO = 25V, RL = 1k 100
110 dB
VO = 25V, RL = 4 100 dBFREQUENCY RESPONSEGain Bandwidth Product
GBW 0.9 MHzSlew Rate SR G = 1, 50Vp-p Step, RL = 4 9 V/sFull-Power
Bandwidth See Typical CurveSettling Time: 0.1% G = 10, 50V Step 20
sTotal Harmonic Distortion + Noise(3) THD+N f = 1kHz,RL = 4,G = +3,
Power = 25W 0.015 %OUTPUTVoltage Output, Positive IO = 2A (V+) 3.2
(V+) 2.7 VNegative IO = 2A (V) + 1.7 (V) + 1.4 VPositive IO = 8A
(V+) 4.8 (V+) 4.3 VNegative IO = 8A (V) + 4.6 (V) + 3.9 VNegative
RL = 8 to V (V) + 0.3 (V) + 0.1 V
Maximum Continuous Current Output: dc(4) 8 Aac(4) Waveform
Cannot Exceed 10A peak 8 A rms
Output Current LimitCurrent Limit Range 0 to 10 ACurrent Limit
Equation ILIM = 15800 4.75V/(7500 + RCL) ACurrent Limit
Tolerance(1) RCL = 7.5k (ILIM = 5A), RL = 4 200 500 mA
Capacitive Load Drive (Stable Operation) CLOAD See Typical
CurveOutput DisabledLeakage Current Output Disabled, VO = 0V 2000
200 +2000 AOutput Capacitance Output Disabled 750 pF
OUTPUT ENABLE/STATUS (E/S) PINShutdown Input ModeVE/S High
(output enabled) E/S Pin Open or Forced High (Ref) + 2.4 VVE/S Low
(output disabled) E/S Pin Forced Low (Ref) + 0.8 VIE/S High (output
enabled) E/S Pin Indicates High 50 AIE/S Low (output disabled) E/S
Pin Indicates Low 55 A
Output Disable Time 1 sOutput Enable Time 3 sThermal Shutdown
Status OutputNormal Operation Sourcing 20A (Ref) + 2.4 (Ref) + 3.5
VThermally Shutdown Sinking 5A, TJ > 160C (Ref) + 0.2 (Ref) +
0.8 V
Junction Temperature, Shutdown +160 CReset from Shutdown +140
C
Ref (Reference Pin for Control Signals)Voltage Range V (V+) 8
VCurrent(2) 3.5 mAPOWER SUPPLYSpecified Voltage VS 30 VOperating
Voltage Range, (V+) (V) 8 60 VQuiescent Current IQ ILIM Connected
to Ref IO = 0 26 35 mAQuiescent Current in Shutdown Mode ILIM
Connected to Ref 6 mATEMPERATURE RANGESpecified Range 40 +85
COperating Range 40 +125 CStorage Range 55 +125 CThermal
Resistance, JC 1.4 C/WThermal Resistance, JA No Heat Sink 30
C/W
NOTES: (1) High-speed test at TJ = +25C. (2) Positive
conventional current is defined as flowing into the terminal. (3)
See Total Harmonic Distortion + Noise vsFrequency in the Typical
Characteristics section for additional power levels. (4) See Safe
Operating Area (SOA) in the Typical Characteristics section.
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TYPICAL CHARACTERISTICSAt TCASE = +25C, VS = 30V, and E/S pin
open, unless otherwise noted.
60 40 20 0 20 40 60 80 140120100
130
120
110
100
90
80
70
60
50
40
Inpu
t Bias Cu
rrent (n
A)
Temperature (C)
INPUT BIAS CURRENT vs TEMPERATURE
IB+IB
30 20 10 0 10 20 30
200180160140120100806040200
Inpu
t Bias Cu
rrent (n
A)
Common-Mode Voltage (V)
INPUT BIAS CURRENTvs COMMON-MODE VOLTAGE
1 10 100 1k 10k 100k 1M 10M
120
100
80
60
40
20
0
20
40
0
20
40
60
80
100
120
140
160
Gain (dB
)
Phase ()
Frequency (Hz)
OPEN-LOOP GAIN AND PHASEvs FREQUENCY
0 5 10 15 20 25 30
9
8
7
6
5
4
3
2
1
0
Curre
nt Limit (A)
Supply Voltage (V)
CURRENT LIMIT vs SUPPLY VOLTAGE
+ILIM, 5A
ILIM, 5A
+ILIM, 2A
ILIM, 2A
+ILIM, 8A
ILIM, 8A
75 50 25 0 25 50 75 100 125
30
25
20
15
10
5
0
Quies
cent Current (m
A)
Temperature (C)
QUIESCENT CURRENT vs TEMPERATURE
VS = 30V
VS = 5V
IQ Shutdown (output disabled)
75 50 25 0 25 50 75 100 125
9
8
7
6
5
4
3
2
1
0
Curre
nt Limit (A)
Temperature (C)
CURRENT LIMIT vs TEMPERATURE
5A
2A
8A
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TYPICAL CHARACTERISTICS (Cont.)At TCASE = +25C, VS = 30V, and
E/S pin open, unless otherwise noted.
1 10 100 1k 10k 100k
300
250
200
150
100
50
0
Voltage
Noise (n
V/H
z)
Frequency (Hz)
VOLTAGE NOISE DENSITY vs FREQUENCY
10 100 1k 10k 100k 1M
120
100
80
60
40
20
0
Power-Sup
ply Re
jection R
atio (
dB)
Frequency (Hz)
POWER-SUPPLY REJECTION RATIOvs FREQUENCY
PSRR
+PSRR
75 50 0 50 100
AOL
125
120
110
100
90
80
A OL, CM
RR, P
SRR (dB
)
Temperature (C)
OPEN-LOOP GAIN, COMMON-MODE REJECTION RATIO,AND POWER-SUPPLY
REJECTION RATIO
vs TEMPERATURE
CMRR
PSRR
20 100 1k 10k 20k
1
0.1
0.01
0.001
THD+N
(%)
Frequency (Hz)
TOTAL HARMONIC DISTORTION + NOISEvs FREQUENCY
G = +3RL = 4
0.1W 1W
10W
75W
75 50 25 0 25 50 75 100 125
1
0.90.80.70.60.50.40.30.20.10
1615
14
1312
11
10987
6
Gain-Ba
ndwidth Prod
uct (M
Hz)
Slew
Rate (V/s
)
Temperature (C)
GAIN-BANDWIDTH PRODUCT ANDSLEW RATE vs TEMPERATURE
SR+
SR
GBW
10 100 1k 10k 100k
100
90
80
70
60
50
40
Common
-Mod
e Re
jection (
dB)
Frequency (Hz)
COMMON-MODE REJECTION RATIO vs FREQUENCY
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TYPICAL CHARACTERISTICS (Cont.)At TCASE = +25C, VS = 30V, and
E/S pin open, unless otherwise noted.
5
4
3
2
1
0
VSU
PPLY
V
OUT (
V)
Temperature (C)
OUTPUT VOLTAGE SWING vs TEMPERATURE
75 50 25 0 25 50 75 100 125
IO = +8A
IO = 8A
IO = +2A
IO = 2A
1k 10k 100k 1M
30
25
20
15
10
5
0
Outpu
t Voltage
(Vp)
Frequency (Hz)
MAXIMUM OUTPUT VOLTAGE SWINGvs FREQUENCY
Maximum outputvoltage without
slew rate-induceddistortion.
0 2 4 6 8 10
5
4
3
2
1
0
VSU
PPLY
V
OUT (
V)
Output Current (A)
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
(V+) VO
(V) VO
40 30 20 10 0 10 20 4030
5
4
3
2
1
0
1
2
3
4
5
Leakag
e Cu
rrent (m
A)
Output Voltage (V)
OUTPUT LEAKAGE CURRENTvs APPLIED OUTPUT VOLTAGE
RCL =
RCL = 0
Leakage current with output disabled.
OFFSET VOLTAGEPRODUCTION DISTRIBUTION
Percen
t of A
mplifie
rs (%
)
Offset Voltage (mV)
4.7
4.2
33.7
63.2
92.8
22.3
51.8
81.4
10.9
40.4
7 00.4
70.9
41.4
11.8
82.3
52.8
23.2
93.7
64.2
3 4.7
25
20
15
10
5
0
OFFSET VOLTAGE DRIFTPRODUCTION DISTRIBUTION
Percen
t of A
mplifie
rs (%
)
Offset Voltage (V/C)
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80
8425
20
15
10
5
0
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TYPICAL CHARACTERISTICS (Cont.)At TCASE = +25C, VS = 30V, and
E/S pin open, unless otherwise noted.
0 5k 10k 15k 20k 25k 30k 35k
70
60
50
40
30
20
10
0
Oversho
ot (%
)
Load Capacitance (pF)
SMALL-SIGNAL OVERSHOOTvs LOAD CAPACITANCE
G = 1
G = +1
LARGE-SIGNAL STEP RESPONSEG = 3, CL = 1000pF
10V/div
5s/div
SMALL-SIGNAL STEP RESPONSEG = 1, CL = 1000pF
50mV/div
2.5s/div
SMALL-SIGNAL STEP RESPONSEG = 3, CL = 1000pF
100m
V/div
2.5s/div
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APPLICATIONS INFORMATIONFigure 1 shows the OPA549 connected as a
basic noninvertingamplifier. The OPA549 can be used in virtually
any op ampconfiguration.Power-supply terminals should be bypassed
with low seriesimpedance capacitors. The technique shown in Figure
1, usinga ceramic and tantalum type in parallel, is
recommended.Power-supply wiring should have low series impedance.Be
sure to connect both output pins (pins 1 and 2).
CONTROL REFERENCE (Ref) PINThe OPA549 features a reference (Ref)
pin to which the ILIMand the E/S pin are referred. Ref simply
provides a referencepoint accessible to the user that can be set to
V, ground, orany reference of the users choice. Ref cannot be set
belowthe negative supply or above (V+) 8V. If the minimum VSis
used, Ref must be set at V.
ADJUSTABLE CURRENT LIMITThe OPA549s accurate, user-defined
current limit can be setfrom 0A to 10A by controlling the input to
the ILIM pin. Unlikeother designs, which use a power resistor in
series with theoutput current path, the OPA549 senses the load
indirectly.This allows the current limit to be set with a 0A to
633Acontrol signal. In contrast, other designs require a
limitingresistor to handle the full output current (up to 10A in
thiscase).Although the design of the OPA549 allows output currents
upto 10A, it is not recommended that the device be
operatedcontinuously at that level. The highest rated
continuouscurrent capability is 8A. Continuously running the OPA549
atoutput currents greater than 8A will degrade long-term
reli-ability.Operation of the OPA549 with current limit less than
1Aresults in reduced current limit accuracy. Applications
requir-ing lower output current may be better suited to the
OPA547or OPA548.Resistor-Controlled Current LimitSee Figure 2a for
a simplified schematic of the internalcircuitry used to set the
current limit. Leaving the ILIM pin openprograms the output current
to zero, while connecting ILIMdirectly to Ref programs the maximum
output current limit,typically 10A.With the OPA549, the simplest
method for adjusting thecurrent limit uses a resistor or
potentiometer connectedbetween the ILIM pin and Ref according to
Equation 1:
R 75kVI
7.5kCLLIM
= (1)
Refer to Figure 2 for commonly used values.Digitally-Controlled
Current LimitThe low-level control signal (0A to 633A) also allows
thecurrent limit to be digitally controlled by setting either
acurrent (ISET) or voltage (VSET). The output current ILIM can
beadjusted by varying ISET according to Equation 2:
ISET = ILIM/15800 (2)Figure 2b demonstrates a circuit
configuration implementingthis feature.The output current ILIM can
be adjusted by varying VSETaccording to Equation 3:
VSET = (Ref) + 4.75V (7500W)(ILIM)/15800 (3)Figure 11
demonstrates a circuit configuration implementingthis feature.
FIGURE 1. Basic Circuit Connections.
POWER SUPPLIESThe OPA549 operates from single (+8V to +60V) or
dual(4V to 30V) supplies with excellent performance. Mostbehavior
remains unchanged throughout the full operatingvoltage range.
Parameters that vary significantly with operat-ing voltage are
shown in the Typical Characteristics. Someapplications do not
require equal positive and negative out-put voltage swing.
Power-supply voltages do not need to beequal. The OPA549 can
operate with as little as 8V betweenthe supplies and with up to 60V
between the supplies. Forexample, the positive supply could be set
to 55V with thenegative supply at 5V. Be sure to connect both V
pins(pins 5 and 7) to the negative power supply, and both V+pins
(pins 10 and 11) to the positive power supply.Package tab is
internally connected to V; however, donot use the tab to conduct
current.
G = 1+ R2R1
ZL
E/S
8
9
10, 11
3
4
5, 76
1, 2
R2
ILIM(1)Ref
R1
0.1F(2)
10F
OPA549
V
V+
+
+
VIN
10F
0.1F(2)
VO
NOTES: (1) ILIM connected to Ref gives the maximum current
limit, 10A (peak). (2) Connect capacitors directly to package
power-supply pins.
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FIGURE 2. Adjustable Current Limit.
ENABLE/STATUS (E/S) PINThe Enable/Status Pin provides two unique
functions:1) output disable by forcing the pin low, and 2)
thermalshutdown indication by monitoring the voltage level at
thepin. Either or both of these functions can be utilized in
anapplication. For normal operation (output enabled), the E/Spin
can be left open or driven high (at least 2.4V above Ref).A small
value capacitor connected between the E/S pin andCREF may be
required for noisy applications.Output DisableTo disable the
output, the E/S pin is pulled to a logic low (nogreater than 0.8V
above Ref). Typically the output is shut downin 1s. To return the
output to an enabled state, the E/S pinshould be disconnected
(open) or pulled to at least 2.4V aboveRef. It should be noted that
driving the E/S pin high (outputenabled) does not defeat internal
thermal shutdown; however,it does prevent the user from monitoring
the thermal shutdownstatus. Figure 3 shows an example implementing
this function.This function not only conserves power during idle
periods(quiescent current drops to approximately 6mA) but also
allowsmultiplexing in multi-channel applications. See Figure 12 for
two
OPA549s in a switched amplifier configuration. The on/off
stateof the two amplifiers is controlled by the voltage on the E/S
pin.Under these conditions, the disabled device will behave like
a750pF load. Slewing faster than 3V/s will cause leakagecurrent to
rapidly increase in devices that are disabled, and willcontribute
additional load. At high temperature (125C), theslewing threshold
drops to approximately 2V/s. Input signalsmust be limited to avoid
excessive slewing in multiplexedapplications.
FIGURE 3. Output Disable.
OPA549E/S
CMOS or TTL
Ref
LogicGround
7500
RCL 0.01F(optional, for noisyenvironments)
8
6
8
6
4.75V
RCL = 7500
OPA549 CURRENT LIMIT: 0A to 10A
NOTES: (1) Resistors are nearest standard 1% values. (2) Offset
in the current limit circuitry may introduce approximately 0.25A
variation at low current limit values.
DESIREDCURRENT LIMIT
0A(2)2.5A3A4A5A6A7A8A9A10A
RESISTOR(1)(RCL)
ILIM Open22.6k17.4k11.3k7.5k4.99k3.24k1.87k845
ILIM Connected to Ref
CURRENT(ISET)0A
158A190A253A316A380A443A506A570A633A
VOLTAGE(VSET)
(Ref) + 4.75V(Ref) + 3.56V(Ref) + 3.33V(Ref) + 2.85V(Ref) +
2.38V(Ref) + 1.90V(Ref) + 1.43V(Ref) + 0.95V(Ref) + 0.48V
(Ref)
(a) RESISTOR METHOD
15800 (4.75V)ILIM
=
7.5k75kILIM
7500
ISET = ILIM/15800
VSET = (Ref) + 4.75V (7500) (ILIM)/15800
(b) DAC METHOD (Current or Voltage)
D/A
ISET4.75V
RefRef
ILIM =
Max IO = ILIM(4.75) (15800)7500 + RCL
Max IO = ILIMILIM =15800 ISET
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Thermal Shutdown StatusThe OPA549 has thermal shutdown circuitry
that protects theamplifier from damage. The thermal protection
circuitry dis-ables the output when the junction temperature
reachesapproximately 160C and allows the device to cool. When
thejunction temperature cools to approximately 140C, the
outputcircuitry is automatically re-enabled. Depending on load
andsignal conditions, the thermal protection circuit may cycle
onand off. The E/S pin can be monitored to determine if thedevice
is in shutdown. During normal operation, the voltage onthe E/S pin
is typically 3.5V above Ref. Once shutdown hasoccurred, this
voltage drops to approximately 200mV aboveRef. Figure 4 shows an
example implementing this function.
FIGURE 4. Thermal Shutdown Status.
FIGURE 5. Output Disable and Thermal Shutdown Status.
FIGURE 6. Safe Operating Area.
External logic circuitry or an LED can be used to indicate ifthe
output has been thermally shutdown, see Figure 10.Output Disable
and Thermal Shutdown StatusAs mentioned earlier, the OPA549s output
can be disabledand the disable status can be monitored
simultaneously.Figure 5 provides an example of interfacing to the
E/S pin.
SAFE OPERATING AREAStress on the output transistors is
determined both by theoutput current and by the output voltage
across the conduct-ing output transistor, VS VO. The power
dissipated by theoutput transistor is equal to the product of the
output currentand the voltage across the conducting transistor, VS
VO.The Safe Operating Area (SOA curve, Figure 6) shows
thepermissible range of voltage and current.
The safe output current decreases as VS VO increases.Output
short circuits are a very demanding case for SOA. Ashort circuit to
ground forces the full power-supply voltage(V+ or V) across the
conducting transistor. Increasing thecase temperature reduces the
safe output current that can betolerated without activating the
thermal shutdown circuit ofthe OPA549. For further insight on SOA,
consult ApplicationReport SBOA022 at the Texas Instruments web
site(www.ti.com).
POWER DISSIPATIONPower dissipation depends on power supply,
signal, and loadconditions. For dc signals, power dissipation is
equal to theproduct of output current times the voltage across the
con-ducting output transistor. Power dissipation can be mini-mized
by using the lowest possible power-supply voltagenecessary to
assure the required output voltage swing.For resistive loads, the
maximum power dissipation occurs ata dc output voltage of one-half
the power-supply voltage.Dissipation with ac signals is lower.
Application BulletinSBOA022 explains how to calculate or measure
powerdissipation with unusual signals and loads.
THERMAL PROTECTIONPower dissipated in the OPA549 will cause the
junctiontemperature to rise. Internal thermal shutdown circuitry
shutsdown the output when the die temperature reaches
approxi-mately 160C and resets when the die has cooled to
140C.Depending on load and signal conditions, the thermal
protec-tion circuit may cycle on and off. This limits the
dissipation ofthe amplifier but may have an undesirable effect on
the load.Any tendency to activate the thermal protection circuit
indi-cates excessive power dissipation or an inadequate heatsink.
For reliable operation, junction temperature should belimited to
125C maximum. To estimate the margin of safetyin a complete design
(including heat sink) increase theambient temperature until the
thermal protection is triggered.
1 2 5 10VS VO (V)
20 50 100
10
20
1
Outpu
t Current (A
)
0.1
Pulse Operation Only(Limit rms current to 8A)
Output current canbe limited to lessthan 8Asee text.
TC = 125C
TC = 85C
TC = 25CPD = 90WPD = 47WPD = 18W
OPA549
E/S
HCT
LogicGround
Ref
E/S pin can interfacewith standard HCT logicinputs. Logic ground
isreferred to Ref.
OPA549E/S
Open Drain(Output Disable)
HCT(Thermal Status
Shutdown)
LogicGround
Ref
Open-drain logic output can disable the amplifier's output with
a logic low.HCT logic input monitors thermal shutdown status during
normal operation.
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Use worst-case load and signal conditions. For good
reliabil-ity, thermal protection should trigger more than 35C
abovethe maximum expected ambient condition of your applica-tion.
This produces a junction temperature of 125C at themaximum expected
ambient condition.The internal protection circuitry of the OPA549
was designedto protect against overload conditions. It was not
intended toreplace proper heat sinking. Continuously running the
OPA549into thermal shutdown will degrade reliability.
AMPLIFIER MOUNTING AND HEAT SINKINGMost applications require a
heat sink to assure that themaximum operating junction temperature
(125C) is notexceeded. In addition, the junction temperature should
bekept as low as possible for increased reliability.
Junctiontemperature can be determined according to the
Equations:
TJ = TA + PDJA (4)where JA = JC + CH + HA (5)
TJ = Junction Temperature (C)TA = Ambient Temperature (C)PD =
Power Dissipated (W)JC = Junction-to-Case Thermal Resistance
(C/W)CH = Case-to-Heat Sink Thermal Resistance (C/W)HA = Heat
Sink-to-Ambient Thermal Resistance (C/W)JA = Junction-to-Air
Thermal Resistance (C/W)
Figure 7 shows maximum power dissipation versus
ambienttemperature with and without the use of a heat sink. Using
aheat sink significantly increases the maximum power dissipa-tion
at a given ambient temperature, as shown in Figure 7.The challenge
in selecting the heat sink required lies indetermining the power
dissipated by the OPA549. For dcoutput, power dissipation is simply
the load current times thevoltage developed across the conducting
output transistor,PD = IL (VS VO). Other loads are not as simple.
Consult theSBOA022 Application Report for further insight on
calculat-ing power dissipation. Once power dissipation for an
applica-tion is known, the proper heat sink can be selected.Heat
Sink Selection ExampleAn 11-lead power ZIP pack-age is dissipating
10 Watts. The maximum expected ambienttemperature is 40C. Find the
proper heat sink to keep thejunction temperature below 125C (150C
minus 25C safetymargin).Combining Equations (4) and (5) gives:
TJ = TA + PD ( JC + CH + HA ) (6)TJ, TA, and PD are given. JC is
provided in the SpecificationsTable, 1.4C/W (dc). CH can be
obtained from the heat sinkmanufacturer. Its value depends on heat
sink size, area, andmaterial used. Semiconductor package type,
mounting screwtorque, insulating material used (if any), and
thermal joint
compound used (if any) also affect CH. A typical CH for amounted
11-lead power ZIP package is 0.5C/W. Now wecan solve for HA:HA =
[(TJ TA)/PD] JC CHHA = [(125C 40C)/10W] 1.4C/W 0.5C/WHA = 6.6C/WTo
maintain junction temperature below 125C, the heat sinkselected
must have a HA less than 6.6C/W. In other words,the heat sink
temperature rise above ambient must be lessthan 66C (6.6C/W 10W).
For example, at 10W Thermalloymodel number 6396B has a heat sink
temperature rise of 56C(HA = 56C/10W = 5.6C/W), which is below the
required 66Crequired in this example. Thermalloy model number 6399B
hasa sink temperature rise of 33C (HA = 33C/10W = 3.3C/W),which is
also below the required 66C required in this example.Figure 7 shows
power dissipation versus ambient temperaturefor a 11-lead power ZIP
package with the Thermalloy 6396Band 6399B heat sinks.
FIGURE 7. Maximum Power Dissipation vs Ambient Temperature.
Another variable to consider is natural convection versusforced
convection air flow. Forced-air cooling by a small fancan lower CA
(CH + HA) dramatically. Some heat sinkmanufacturers provide thermal
data for both of these cases.Heat sink performance is generally
specified under idealizedconditions that may be difficult to
achieve in an actualapplication. For additional information on
determining heatsink requirements, consult Application Report
SBOA021.
0 25 50 75 100 125
30
20
10
0
Power Dissipa
tion (W
)
Ambient Temperature (C)
Thermalloy 6399B HA = 5.6C/W assume CH = 0.5C/WOPA549 JC =
1.4C/W
JA = 7.5C/W
Thermalloy 6396B HA = 3.3C/W assume CH = 0.5C/W
OPA549 JC = 1.4C/W JA = 5.2C/W
with Thermalloy 6396BHeat Sink, JA = 7.5C/W
with Thermalloy 6399BHeat Sink, JA = 5.2C/W
PD = (TJ (max) TA)/ JA(TJ (max) 150C)
with No Heat Sink, JA = 30C/W
-
OPA549SBOS093E
12www.ti.com
avoided with clamp diodes from the output terminal to thepower
supplies, as shown in Figure 8. Schottky rectifierdiodes with a 8A
or greater continuous rating are recom-mended.
VOLTAGE SOURCE APPLICATIONFigure 9 illustrates how to use the
OPA549 to provide anaccurate voltage source with only three
external resistors.First, the current limit resistor, RCL, is
chosen according tothe desired output current. The resulting
voltage at the ILIMpin is constant and stable over temperature.
This voltage,VCL, is connected to the noninverting input of the op
amp andused as a voltage reference, thus eliminating the need for
anexternal reference. The feedback resistors are selected togain
VCL to the desired output voltage level.
As mentioned earlier, once a heat sink has been selected,the
complete design should be tested under worst-case loadand signal
conditions to ensure proper thermal protection.Any tendency to
activate the thermal protection circuitry mayindicate inadequate
heat sinking.The tab of the 11-lead power ZIP package is
electricallyconnected to the negative supply, V. It may be
desirable toisolate the tab of the 11-lead power ZIP package from
itsmounting surface with a mica (or other film) insulator.
Forlowest overall thermal resistance, it is best to isolate
theentire heat sink/OPA549 structure from the mounting
surfacerather than to use an insulator between the semiconductorand
heat sink.
OUTPUT STAGE COMPENSATIONThe complex load impedances common in
power op ampapplications can cause output stage instability. For
normaloperation, output compensation circuitry is typically not
re-quired. However, for difficult loads or if the OPA549 is
in-tended to be driven into current limit, an R/C network may
berequired. Figure 8 shows an output R/C compensation (snub-ber)
network which generally provides excellent stability.
FIGURE 8. Motor Drive Circuit.
FIGURE 9. Voltage Source.
G = = 4R2R1
10(Carbon)0.01F
R220k
R15k
OPA549
V
V+
VIN
Motor
D1
D2
D1, D2 : Schottky Diodes
7500
RCL
ILIM
0.01F(Optional, for noisy
environments)
4.75V
IO =15800 (4.75V)7500 + RCL
VO = VCL (1 + R2/R1)
Ref
V+
VCL
VCL = = 1V
Desired VO = 10V,
R1 = 1k and R2 = 9k
G = = 10101
For Example:
2k 4.75V(2k + 7500)
If ILIM = 7.9A, RCL = 2k
V
R2R1
Uses voltage developed at ILIM pin as a moderately accurate
reference voltage.
A snubber circuit may also enhance stability when drivinglarge
capacitive loads (> 1000pF) or inductive loads (motors,loads
separated from the amplifier by long cables). Typically,3 to 10
resistors in series with 0.01F to 0.1F capacitorsis adequate. Some
variations in circuit values may be requiredwith certain loads.
OUTPUT PROTECTIONReactive and EMF-generating loads can return
load currentto the amplifier, causing the output voltage to exceed
thepower-supply voltage. This damaging condition can be
PROGRAMMABLE POWER SUPPLYA programmable source/sink power supply
can easily bebuilt using the OPA549. Both the output voltage and
outputcurrent are user-controlled. See Figure 10 for a circuit
usingpotentiometers to adjust the output voltage and current
whileFigure 11 uses DACs. An LED connected to the E/S pinthrough a
logic gate indicates if the OPA549 is in thermalshutdown.
-
OPA549SBOS093E
13www.ti.com
FIGURE 10. Resistor-Controlled Programmable Power Supply.
FIGURE 11. Digitally-Controlled Programmable Power Supply.
G = 1 + = 109k1k
9k1k
OPA549
+5V
+5V
0.12V to 2.5V
0V to 4.75V
OutputAdjust
ThermalShutdown Status
(LED)
74HCT04 R 250
E/SVO = 1V to 25VIO = 0 to 10A9
6
8
4
3
RefILIM
10.5k
499
10k
CurrentLimitAdjust
1k
20k 0.01F
V
V+ = +30VV = 0V
DAC B1/2 DAC7800/1/2
1/2 DAC7800/1/2(3)
10pF
IOUT B
RFB B
AGND B0.01F
ILIM
ThermalShutdown Status
(LED)
74HCT04 R 250
9k1k
VO = 7V to 25V
V+ = +30VV = 0V
IO = 0A to 10A
G = 10
Ref8
9
1, 2
E/S6
4
3
DAC A
+5V
+5V
VREF B
DGND
10pF
IOUT A
RFB A
OUTPUT ADJUST
OPA549
CURRENT LIMIT ADJUST
AGND A
VREF A
Choose DAC780X based on digital interface: DAC780012-bit
interface, DAC78018-bit interface + 4 bits, DAC7802serial
interface.
1/2OPA2336
1/2OPA2336
VREF
5V
-
OPA549SBOS093E
14www.ti.com
FIGURE 13. Multiple Current Limit Values.FIGURE 12. Switched
Amplifier.
FIGURE 14. Parallel Output for Increased Output Current.
E/S
R2R1VIN1
OPA549
VO
E/S
R4R3
Limit output slew rates to 3V/s (see text).
VE/S VIN2
OPA549
OPA549
RCL2RCL1
Ref
Close for high current(could be open drainoutput of a logic
gate).
ILIM
ILIMRef
Ref
R11k
R24k
OPA549
OPA549
VOG = 5
VIN
0.1
0.1
ILIM
Master
Slave
20A Peak
-
PACKAGE OPTION ADDENDUM
www.ti.com 22-Oct-2013
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status(1)
Package Type PackageDrawing
Pins PackageQty
Eco Plan(2)
Lead/Ball Finish(6)
MSL Peak Temp(3)
Op Temp (C) Device Marking(4/5)
Samples
OPA549S ACTIVE Power Package KVC 11 25 Green (RoHS& no
Sb/Br)
CU SN N / A for Pkg Type -40 to 85 OPA549S
OPA549SG3 ACTIVE Power Package KVC 11 25 Green (RoHS& no
Sb/Br)
CU SN N / A for Pkg Type -40 to 85 OPA549S
OPA549T ACTIVE TO-220 KV 11 25 Green (RoHS& no Sb/Br)
CU SN N / A for Pkg Type -40 to 85 OPA549T
OPA549TG3 ACTIVE TO-220 KV 11 25 Green (RoHS& no Sb/Br)
CU SN N / A for Pkg Type -40 to 85 OPA549T
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.LIFEBUY: TI
has announced that the device will be discontinued, and a
lifetime-buy period is in effect.NRND: Not recommended for new
designs. Device is in production to support existing customers, but
TI does not recommend using this part in a new design.PREVIEW:
Device has been announced but is not in production. Samples may or
may not be available.OBSOLETE: TI has discontinued the production
of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free
(RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) -
please check http://www.ti.com/productcontent for the latest
availability
information and additional product content details.TBD: The
Pb-Free/Green conversion plan has not been defined.Pb-Free (RoHS):
TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products
that are compatible with the current RoHS requirements for all 6
substances, including the requirement thatlead not exceed 0.1% by
weight in homogeneous materials. Where designed to be soldered at
high temperatures, TI Pb-Free products are suitable for use in
specified lead-free processes.Pb-Free (RoHS Exempt): This component
has a RoHS exemption for either 1) lead-based flip-chip solder
bumps used between the die and package, or 2) lead-based die
adhesive used betweenthe die and leadframe. The component is
otherwise considered Pb-Free (RoHS compatible) as defined
above.Green (RoHS & no Sb/Br): TI defines "Green" to mean
Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony
(Sb) based flame retardants (Br or Sb do not exceed 0.1% by
weightin homogeneous material)
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating
according to the JEDEC industry standard classifications, and peak
solder temperature.
(4) There may be additional marking, which relates to the logo,
the lot trace code information, or the environmental category on
the device.
(5) Multiple Device Markings will be inside parentheses. Only
one Device Marking contained in parentheses and separated by a "~"
will appear on a device. If a line is indented then it is a
continuation
of the previous line and the two combined represent the entire
Device Marking for that device.
(6) Lead/Ball Finish - Orderable Devices may have multiple
material finish options. Finish options are separated by a vertical
ruled line. Lead/Ball Finish values may wrap to two lines if the
finish
value exceeds the maximum column width.
-
PACKAGE OPTION ADDENDUM
www.ti.com 22-Oct-2013
Addendum-Page 2
Important Information and Disclaimer:The information provided on
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In no event shall TI's liability arising out of such information
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document sold by TI to Customer on an annual basis.
-
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