Texas Instruments | LM675 Power Operational Amplifier (Rev. E) | Datasheet | Texas Instruments LM675 Power Operational Amplifier (Rev. E) Datasheet

Texas Instruments LM675 Power Operational Amplifier (Rev. E) Datasheet
LM675
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SNOSBP3E – MAY 1999 – REVISED MARCH 2013
LM675 Power Operational Amplifier
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FEATURES
1
•
•
•
•
•
•
•
•
2
•
•
•
•
•
3A Current Capability
AVO Typically 90 dB
5.5 MHz Gain Bandwidth Product
8 V/μs Slew Rate
Wide Power Bandwidth 70 kHz
1 mV Typical Offset Voltage
Short Circuit Protection
Thermal Protection with Parole Circuit (100%
Tested)
16V–60V Supply Range
Wide Common Mode Range
Internal Output Protection Diodes
90 dB Ripple Rejection
Plastic Power Package TO-220
Connection Diagram
*The tab is internally connected to pin 3
(−VEE)
Figure 1. Front View
TO-220 Power Package (NDH)
See Package Number NDH0005D
Typical Applications
APPLICATIONS
•
•
•
•
•
High Performance Power Op Amp
Bridge Amplifiers
Motor Speed Controls
Servo Amplifiers
Instrument Systems
DESCRIPTION
The LM675 is a monolithic power operational
amplifier featuring wide bandwidth and low input
offset voltage, making it equally suitable for AC and
DC applications.
The LM675 is capable of delivering output currents in
excess of 3 amps, operating at supply voltages of up
to 60V. The device overload protection consists of
both internal current limiting and thermal shutdown.
The amplifier is also internally compensated for gains
of 10 or greater.
Figure 2. Non-Inverting Amplifier
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
ABSOLUTE MAXIMUM RATINGS (1) (2)
Supply Voltage
±30V
−VEE to VCC
Input Voltage
Operating Temperature
0°C to +70°C
Storage Temperature
−65°C to +150°C
Junction Temperature
150°C
Power Dissipation
(3)
30W
Lead Temperature
(Soldering, 10 seconds)
260°C
ESD rating to be determined.
(1)
(2)
(3)
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional, but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
Assumes TA equal to 70°C. For operation at higher tab temperatures, the LM675 must be derated based on a maximum junction
temperature of 150°C.
ELECTRICAL CHARACTERISTICS
VS=±25V, TA=25°C unless otherwise specified.
Parameter
Conditions
Typical
Tested Limit
Units
18
50 (max)
mA
VCM = 0V
1
10 (max)
mV
VCM = 0V
0.2
2 (max)
μA
Input Offset Current
VCM = 0V
50
500 (max)
nA
Open Loop Gain
RL = ∞Ω
90
70 (min)
dB
PSRR
ΔVS = ±5V
90
70 (min)
dB
CMRR
VIN = ±20V
90
70 (min)
dB
Output Voltage Swing
RL = 8Ω
±21
±18 (min)
V
Offset Voltage Drift Versus Temperature
RS < 100 kΩ
25
Supply Current
POUT = 0W
Input Offset Voltage
Input Bias Current
Offset Voltage Drift Versus Output Power
Output Power
THD = 1%, fO = 1 kHz, RL = 8Ω
25
Gain Bandwidth Product
fO = 20 kHz, AVCL = 1000
5.5
Max Slew Rate
μV/W
20
±22
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W
MHz
8
Input Common Mode Range
2
μV/°C
25
V/μs
±20 (min)
V
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TYPICAL APPLICATIONS
VS = ±8V → ±30V
Figure 3. Generating a Split Supply From a Single Supply
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TYPICAL PERFORMANCE CHARACTERISTICS
THD vs Power Output
Input Common Mode Range vs Supply Voltage
Figure 4.
Figure 5.
Supply Current vs Supply Voltage
PSRR vs Frequency
Figure 6.
Figure 7.
Device Dissipation vs Ambient Temperature†
Current Limit vs Output Voltage*
†θ INTERFACE = 1° C/W
See APPLICATION HINTS.
*VS = ±25V
Figure 8.
4
Figure 9.
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TYPICAL PERFORMANCE CHARACTERISTICS (continued)
IB vs Supply Voltage
Output Voltage Swing vs Supply Voltage
Figure 10.
Figure 11.
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SCHEMATIC DIAGRAM
6
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APPLICATION HINTS
STABILITY
The LM675 is designed to be stable when operated at a closed-loop gain of 10 or greater, but, as with any other
high-current amplifier, the LM675 can be made to oscillate under certain conditions. These usually involve
printed circuit board layout or output/input coupling.
When designing a printed circuit board layout, it is important to return the load ground, the output compensation
ground, and the low level (feedback and input) grounds to the circuit board ground point through separate paths.
Otherwise, large currents flowing along a ground conductor will generate voltages on the conductor which can
effectively act as signals at the input, resulting in high frequency oscillation or excessive distortion. It is advisable
to keep the output compensation components and the 0.1 μF supply decoupling capacitors as close as possible
to the LM675 to reduce the effects of PCB trace resistance and inductance. For the same reason, the ground
return paths for these components should be as short as possible.
Occasionally, current in the output leads (which function as antennas) can be coupled through the air to the
amplifier input, resulting in high-frequency oscillation. This normally happens when the source impedance is high
or the input leads are long. The problem can be eliminated by placing a small capacitor (on the order of 50 pF to
500 pF) across the circuit input.
Most power amplifiers do not drive highly capacitive loads well, and the LM675 is no exception. If the output of
the LM675 is connected directly to a capacitor with no series resistance, the square wave response will exhibit
ringing if the capacitance is greater than about 0.1 μF. The amplifier can typically drive load capacitances up to 2
μF or so without oscillating, but this is not recommended. If highly capacitive loads are expected, a resistor (at
least 1Ω) should be placed in series with the output of the LM675. A method commonly employed to protect
amplifiers from low impedances at high frequencies is to couple to the load through a 10Ω resistor in parallel with
a 5 μH inductor.
CURRENT LIMIT AND SAFE OPERATING AREA (SOA) PROTECTION
A power amplifier's output transistors can be damaged by excessive applied voltage, current flow, or power
dissipation. The voltage applied to the amplifier is limited by the design of the external power supply, while the
maximum current passed by the output devices is usually limited by internal circuitry to some fixed value. Shortterm power dissipation is usually not limited in monolithic operational power amplifiers, and this can be a problem
when driving reactive loads, which may draw large currents while high voltages appear on the output transistors.
The LM675 not only limits current to around 4A, but also reduces the value of the limit current when an output
transistor has a high voltage across it.
When driving nonlinear reactive loads such as motors or loudspeakers with built-in protection relays, there is a
possibility that an amplifier output will be connected to a load whose terminal voltage may attempt to swing
beyond the power supply voltages applied to the amplifier. This can cause degradation of the output transistors
or catastrophic failure of the whole circuit. The standard protection for this type of failure mechanism is a pair of
diodes connected between the output of the amplifier and the supply rails. These are part of the internal circuitry
of the LM675, and needn't be added externally when standard reactive loads are driven.
THERMAL PROTECTION
The LM675 has a sophisticated thermal protection scheme to prevent long-term thermal stress to the device.
When the temperature on the die reaches 170°C, the LM675 shuts down. It starts operating again when the die
temperature drops to about 145°C, but if the temperature again begins to rise, shutdown will occur at only 150°C.
Therefore, the device is allowed to heat up to a relatively high temperature if the fault condition is temporary, but
a sustained fault will limit the maximum die temperature to a lower value. This greatly reduces the stresses
imposed on the IC by thermal cycling, which in turn improves its reliability under sustained fault conditions. This
circuitry is 100% tested without a heat sink.
Since the die temperature is directly dependent upon the heat sink, the heat sink should be chosen for thermal
resistance low enough that thermal shutdown will not be reached during normal operaton. Using the best heat
sink possible within the cost and space constraints of the system will improve the long-term reliability of any
power semiconductor.
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POWER DISSIPATION AND HEAT SINKING
The LM675 should always be operated with a heat sink, even though at idle worst case power dissipation will be
only 1.8W (30 mA × 60V) which corresponds to a rise in die temperature of 97°C above ambient assuming θjA =
54°C/W for a TO-220 package. This in itself will not cause the thermal protection circuitry to shut down the
amplifier when operating at room temperature, but a mere 0.9W of additional power dissipation will shut the
amplifier down since TJ will then increase from 122°C (97°C + 25°C) to 170°C.
In order to determine the appropriate heat sink for a given application, the power dissipation of the LM675 in that
application must be known. When the load is resistive, the maximum average power that the IC will be required
to dissipate is approximately:
where
•
•
•
VS is the total power supply voltage across the LM675
RL is the load resistance
PQ is the quiescent power dissipation of the amplifier
The above equation is only an approximation which assumes an “ideal” class B output stage and constant power
dissipation in all other parts of the circuit. As an example, if the LM675 is operated on a 50V power supply with a
resistive load of 8Ω, it can develop up to 19W of internal power dissipation. If the die temperature is to remain
below 150°C for ambient temperatures up to 70°C, the total junction-to-ambient thermal resistance must be less
than
Using θJC = 2°C/W, the sum of the case-to-heat sink interface thermal resistance and the heat-sink-to-ambient
thermal resistance must be less than 2.2°C/W. The case-to-heat-sink thermal resistance of the TO-220 package
varies with the mounting method used. A metal-to-metal interface will be about 1°C/W if lubricated, and about
1.2°C/W if dry. If a mica insulator is used, the thermal resistance will be about 1.6°C/W lubricated and 3.4°C/W
dry. For this example, we assume a lubricated mica insulator between the LM675 and the heat sink. The heat
sink thermal resistance must then be less than
4.2°C/W − 2°C/W − 1.6°C/W = 0.6°C/W.
(1)
This is a rather large heat sink and may not be practical in some applications. If a smaller heat sink is required
for reasons of size or cost, there are two alternatives. The maximum ambient operating temperature can be
restricted to 50°C (122°F), resulting in a 1.6°C/W heat sink, or the heat sink can be isolated from the chassis so
the mica washer is not needed. This will change the required heat sink to a 1.2°C/W unit if the case-to-heat-sink
interface is lubricated.
The thermal requirements can become more difficult when an amplifier is driving a reactive load. For a given
magnitude of load impedance, a higher degree of reactance will cause a higher level of power dissipation within
the amplifier. As a general rule, the power dissipation of an amplifier driving a 60° reactive load will be roughly
that of the same amplifier driving the resistive part of that load. For example, some reactive loads may at some
frequency have an impedance with a magnitude of 8Ω and a phase angle of 60°. The real part of this load will
then be 8Ω × cos 60° or 4Ω, and the amplifier power dissipation will roughly follow the curve of power dissipation
with a 4Ω load.
8
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Typical Applications
Figure 12. Non-Inverting Unity Gain Operation
Figure 13. Inverting Unity Gain Operation
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Figure 14. Servo Motor Control
IOUT = VIN × 2.5 amps/volt
i.e. IOUT = 1A when VIN = 400 mV
Trim pot for max ROUT
Figure 15. High Current Source/Sink
10
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REVISION HISTORY
Changes from Revision D (March 2013) to Revision E
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 10
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PACKAGE OPTION ADDENDUM
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21-May-2019
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LM675T
ACTIVE
TO-220
NDH
5
45
TBD
Call TI
Call TI
0 to 70
LM675T
LM675T/LF02
ACTIVE
TO-220
NEB
5
45
Green (RoHS
& no Sb/Br)
CU SN
Level-1-NA-UNLIM
0 to 70
LM675T
LM675T/LF05
ACTIVE
TO-220
NEB
5
45
Green (RoHS
& no Sb/Br)
CU SN
Level-1-NA-UNLIM
0 to 70
LM675T
LM675T/NOPB
ACTIVE
TO-220
NDH
5
45
Green (RoHS
& no Sb/Br)
CU SN
Level-1-NA-UNLIM
0 to 70
LM675T
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(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.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
Addendum-Page 1
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PACKAGE OPTION ADDENDUM
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continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
MECHANICAL DATA
NEB0005B
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MECHANICAL DATA
NDH0005D
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