Texas Instruments | LM138QML Military Grade 5-A Adjustable Output Linear Regulator | Datasheet | Texas Instruments LM138QML Military Grade 5-A Adjustable Output Linear Regulator Datasheet

Texas Instruments LM138QML Military Grade 5-A Adjustable Output Linear Regulator Datasheet
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LM138QML
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LM138QML Military Grade 5-A Adjustable Output Linear Regulator
1 Features
•
1
•
•
•
•
•
•
•
•
A unique feature of the LM138QML device is timedependent current limiting. The current limit circuitry
allows peak currents of up to 12 A to be drawn from
the regulator for short periods of time. This allows the
LM138QML device to be used with heavy transient
loads and speeds start-up under full-load conditions.
Under sustained loading conditions, the current limit
decreases to a safe value protecting the regulator.
Also included on the chip are thermal overload
protection and safe area protection for the power
transistor. Overload protection remains functional
even if the adjustment pin is accidentally
disconnected.
Manufactured and Tested per Texas Instruments
Military Grade Flow
Specified 7-A Peak Output Current
Specified 5-A Output Current
Wide Temperature Range –55°C to 150°C
Adjustable Output Down to 1.2 V
Specified Thermal Regulation
Current Limit Constant With Temperature
P+ Product Enhancement Tested
Output is Short-Circuit Protected
Normally, no capacitors are needed unless the device
is situated more than 6 inches from the input filter
capacitors, in which case an input bypass is needed.
An output capacitor can be added to improve
transient response, while bypassing the adjustment
pin will increase the regulator's ripple rejection.
2 Applications
•
•
•
Adjustable Power Supplies
Constant Current Regulators
Battery Chargers
Besides replacing fixed regulators or discrete
designs, the LM138QML is useful in a wide variety of
other applications. Since the regulator is “floating”
and sees only the input-to-output differential voltage,
supplies of several hundred volts can be regulated as
long as the maximum input to output differential is not
exceeded; that is, do not short-circuit output to
ground.
3 Description
The LM138QML adjustable 3-terminal positive
voltage regulator is capable of supplying in excess of
5 A over a 1.2-V to 32-V output range. The device is
exceptionally easy to use and requires only two
resistors to set the output voltage. Careful circuit
design has resulted in outstanding load and line
regulation—comparable to many commercial power
supplies.
Device Information(1)
PART NUMBER
GRADE
PACKAGE
LM138K-MIL
Military
TO-3 (2)
LM138KG-MD8
Military
Die
LM138KG-MW8
Military
Wafer
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
LM138QML
VOUT
VIN
ADJ
I1
VREF
R1
VOUT
IADJ
R2
Copyright © 2017, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
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Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
4
4
5
5
6
7
Absolute Maximum Ratings ......................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Quality Conformance Inspection ...............................
Typical Performance Characteristics ........................
7.4 Device Functional Modes........................................ 11
8
Application and Implementation ........................ 12
8.1 Application Information............................................ 12
8.2 Typical Applications ................................................ 13
8.3 System Examples ................................................... 17
9 Power Supply Recommendations...................... 29
10 Layout................................................................... 29
10.1 Layout Guidelines ................................................. 29
10.2 Layout Example .................................................... 29
11 Device and Documentation Support ................. 30
11.1
11.2
11.3
11.4
11.5
Detailed Description ............................................ 10
7.1 Overview ................................................................. 10
7.2 Functional Block Diagram ....................................... 10
7.3 Feature Description................................................. 10
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
30
30
30
30
30
12 Mechanical, Packaging, and Orderable
Information ........................................................... 30
4 Revision History
2
DATE
REVISION
NOTES
October 2017
*
Initial release.
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5 Pin Configuration and Functions
K Package
2-Pin TO-3
Bottom View
ADJUSTMENT
VIN
CASE IS
OUTPUT
Package Number K0002C
Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
ADJ
1
I
Output voltage adjustment pin. Connect to a resistor divider to set VO.
VIN
2
I
Supply input pin.
Case
O
Voltage output pin.
VOUT
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
Power dissipation
MAX
UNIT
Internally limited
Input and output voltage differential
–0.3
40
V
Storage temperature, Tstg
–65
150
°C
300
°C
Lead temperature (soldering, 10 seconds)
(1)
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
Operating temperature, TJ
Input-to-output voltage differential
Output current
4
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MIN
MAX
UNIT
–55
150
°C
3
40
V
5
A
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6.3 Thermal Information
LM138QML
THERMAL METRIC (1)
K (TO-3)
UNIT
2 PINS
RθJA
Junction-to-ambient thermal resistance
42.8
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
3.3
°C/W
ψJT
Junction-to-top characterization parameter
2.5
°C/W
ψJB
Junction-to-board characterization parameter
37.4
°C/W
(1)
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
6.4 Electrical Characteristics
Values apply for VIN – VOUT = 5 V; and IOUT = 10 mA (unless otherwise noted) (1)
PARAMETER
VREF
VRLINE
Reference voltage
Line regulation (4)
SUBGROUPS
MIN
VIN – VOUT = 3 V (3)
[1, 2, 3]
1.19
1.29
VIN – VOUT = 3 V, IOUT = 5 A
[1, 2, 3]
1.19
1.29
VIN – VOUT = 5 V, IOUT = 7 A
[1, 2, 3]
1.19
1.29
VIN – VOUT = 35 V
[1, 2, 3]
1.19
1.29
VIN – VOUT = 35 V, IOUT = 150 mA
[1, 2, 3]
1.19
1.29
[1]
–3.5
3.5
[2, 3]
–14
14
[1]
–3.8
3.8
–8
8
–3.8
3.8
–8
8
TEST CONDITIONS
3 V ≤ (VIN – VOUT) ≤ 35 V
3.3 V ≤ (VIN – VOUT) ≤ 35 V
VIN – VOUT = 3 V, 10 mA ≤ IOUT ≤ 5 A,
VOUT = VREF
VRLOAD
Load regulation (4)
VIN – VOUT = 3.3 V, 10 mA ≤ IOUT ≤ 5 A,
VOUT = VREF
VIN – VOUT = 35 V, 10 mA ≤ IOUT ≤ 150
mA, VOUT = VREF
VRTH
Thermal regulation
IADJ
Adjustment pin current
ΔIADJ
Adjustment pin current change
ILOAD(MIN) Minimum load current
ICL
Current limit
ΔVR/ΔVIN Ripple rejection ratio
(1)
(2)
(3)
(4)
(5)
(6)
VIN – VOUT = 10 V, pulse = 20 ms,
IOUT = 1 A (5)
VIN – VOUT = 3 V
(3)
[2, 3]
[1]
[2, 3]
[1]
TYP (2)
MAX
0.002
0.01
45
100
[1, 2, 3]
2
VIN – VOUT = 35 V
[1, 2, 3]
2
3 V ≤ (VIN – VOUT) ≤ 35 V (3)
[1, 2, 3]
–5
10 mA ≤ IOUT ≤ 5 A
[1, 2, 3]
–5
5
VIN – VOUT = 3 V, VOUT = 1.4 V (3)
[1, 2, 3]
0.5
5
VIN – VOUT = 35 V, VOUT = 1.4 V
[1, 2, 3]
0.5
VIN – VOUT = 10 V, T = 0.5 ms,
VOUT = 0 V
[1, 2, 3]
7
16
T = 5 ms, VOUT = 0 V
[1, 2, 3]
5
15
[4]
60
VOUT = VREF, eIN = 1 VRMS, f = 120 Hz,
IOUT = 500 mA (6)
100
0.2
3.5
5
5
UNIT
V
mV
mV
%/W
μA
μA
mA
A
dB
These specifications are applicable for power dissipations up to 50W. Power dissipation is specified at these values up to 15-V inputoutput differential. Above 15-V differential, power dissipation will be limited by internal protection circuitry. All limits (that is, the numbers
in the minimum and maximum columns) are specified to TI's AOQL (Average Outgoing Quality Level).
Typical figures are at TA = 25°C, and represent most likely parametric norms. Test limits are ensured to Texas Instruments' average
outgoing quality level (AOQL).
VIN – VOUT = 3.3 V at –55°C and 125°C.
Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to
heating effects are covered under the specifications for thermal regulation.
Datalog reading in mV, 0.01% = 1.19 mV.
Family board not required for this device.
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6.5 Quality Conformance Inspection
MIL-STD-883, Method 5005 - Group A
6
SUBGROUP
DESCRIPTION
1
Static tests at
25
2
Static tests at
125
3
Static tests at
–55
4
Dynamic tests at
25
5
Dynamic tests at
125
6
Dynamic tests at
–55
7
Functional tests at
25
8A
Functional tests at
125
8B
Functional tests at
–55
9
Switching tests at
25
10
Switching tests at
125
11
Switching tests at
–55
12
Setting time at
25
13
Setting time at
125
14
Setting time at
–55
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TEMPERATURE (°C)
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6.6 Typical Performance Characteristics
Figure 1. Current Limit
Figure 2. Current Limit
Figure 3. Current Limit
Figure 4. Load Regulation
Figure 6. Adjustment Current
Figure 5. Dropout Voltage
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Typical Performance Characteristics (continued)
Figure 7. Temperature Stability
8
Figure 8. Output Impedance
Figure 9. Minimum Operating Current
Figure 10. Ripple Rejection
Figure 11. Ripple Rejection
Figure 12. Ripple Rejection
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Typical Performance Characteristics (continued)
Figure 13. Line Transient Response
Figure 14. Load Transient Response
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7 Detailed Description
7.1 Overview
The LM138QML device is an adjustable, three-terminal, positive-voltage regulator capable of supplying more
than 5 A over an output-voltage range of 1.2 V to 32 V. It requires only two external resistors to set the output
voltage. The LM138QML device features a typical line regulation of 0.005% and typical load regulation of 0.1%. It
includes time-dependent current limiting, thermal overload protection, and safe operating area protection.
Overload protection remains functional even if the ADJUST terminal is disconnected.
The LM138QML devices are versatile in their applications, including uses in programmable output regulation and
local on-card regulation. Or, by connecting a fixed resistor between the ADJUST and OUTPUT terminals, the
LM138QML device can function as a precision current regulator. An optional output capacitor can be added to
improve transient response. The ADJUST terminal can be bypassed to achieve very high ripple-rejection ratios,
which are difficult to achieve with standard three-terminal regulators.
7.2 Functional Block Diagram
VIN
R1
310
R2
310
R3
190
R4
82
R5
5.6 k
Q21
Q10
R19
370
Q25
Q4
Q1
Q8
R17
12 k
D2
6.3 V
Q26
Q20
Q27
Q16
R6
200 k
R8
12.4 k
R7
130
Q17
Q7
Q11
R21
400
R22
160
R20
13 k
Q19
D3
6.3 V
Q24
Q12
C1
30 pF
R15
2.4 k
Q5
R9
180
R23
18 k
Q21
Q15
Q9
Q6
D1
6.3 V
C3
5 pF
Q13
R27
4k
Q3
R16
6.7 k
Q18
Q14
Q2
R18
130
R24
160
R10
4.1 k
R11
5.8 k
R12
72
R13
5.1 k
C2
30 pF
R14
12 k
R26
0.03
R25
3
VOUT
ADJ
6V
Copyright © 2017, Texas Instruments Incorporated
7.3 Feature Description
7.3.1 NPN Darlington Output Drive
NPN Darlington output topology provides naturally low output impedance and an output capacitor is optional. To
support maximum current and lowest temperature, 3-V headroom is recommended (VI – VO).
7.3.2 Overload Block
Overcurrent and overtemperature shutdown protects the device against overload or damage from operating in
excessive heat.
7.3.3 Programmable Feedback
An op amp with 1.25-V offset input at the ADJUST terminal provides easy output voltage or current, but not both,
programming. For current regulation applications, a single resistor whose resistance value is 1.25 V/IO and power
rating is greater than 1.25 V2/R must be used. For voltage regulation applications, two resistors set the output
voltage.
10
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7.4 Device Functional Modes
7.4.1 Normal Operation
The device OUTPUT pin sources current necessary to make the OUTPUT pin 1.25-V greater than the ADJUST
terminal to provide output regulation.
7.4.2 Operation With Low Input Voltage
The device requires up to 3-V headroom (VI – VO) to operate in regulation. With less headroom, the device may
drop out and the OUTPUT voltage is then the INPUT voltage minus the drop out voltage.
7.4.3 Operation at Light Loads
The device passes its bias current to the OUTPUT pin. The load or feedback must consume this minimum
current for regulation or the output may be too high. A 250-Ω feedback resistor between OUTPUT and ADJUST
consumes the worst case minimum load current of 5 mA.
7.4.4 Operation in Self Protection
When an overload occurs, the device shuts down the Darlington NPN output stage or reduces the output current
to prevent device damage. The device automatically resets from the overload. The output may be reduced or
alternate between on and off until the overload is removed.
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
In operation, the LM138QML device develops a nominal 1.25-V reference voltage, VREF, between the output and
adjustment terminal. The reference voltage is impressed across program resistor R1 and, since the voltage is
constant, a constant current I1 then flows through the output set resistor R2, giving an output voltage of:
R1
(1)
LM138QML
VOUT
VIN
ADJ
I1
VREF
R1
VOUT
IADJ
R2
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Because the 50-μA current from the adjustment terminal represents an error term, the LM138QML was designed
to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current
is returned to the output establishing a minimum load current requirement. If there is insufficient load on the
output, the output rises.
12
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8.2 Typical Applications
8.2.1 Constant 5-V Regulator
D1**
1N4002
LM138QML
VIN
VIN
VOUT
VOUT‚‚
ADJ
R1
270
D2‚*
1N4002
CIN*
0.1…F
COUT‚
1…F
CADJ
10…F
R2
820
GND
*Needed if device is more than 6 inches from filter
capacitors
‚2SWLRQDO±±improves transient response
**Recommended if COUT is used
‚‚ VOUT
§
1 . 25 V ¨ 1
©
R2 ·
¸
R1 ¹
I ADJ R 2
‚*Recommended if CADJ is used
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Figure 15. Constant 5-V Regulator
8.2.1.1 Design Requirements
Table 1. Design Parameters
PARAMETER
PART
NUMBER/VALUE
Feedback resistor 1 (R1)
270 Ω
The LM138QML produces a typical 1.24-V potential between the OUTPUT and ADJUST
pins; therefore, placing a 270-Ω resistor between the OUTPUT and ADJUST pins causes
4.6 mA to flow through R1 and R2
Feedback resistor 2 (R2)
820 Ω
To achieve a 5-V output, the sum of the voltages across R1 and R2 must equal 5 V.
Therefore, VR2 must equal 3.76 V when 4.6 mA is flowing through it. R2 = VR2 / I = 3.76 V
/ 4.6 mA = ~820 Ω.
Input capacitor (CIN)
0.1 µF
0.1 µF of input capacitance helps filter out unwanted noise, especially if the regulator is
located far from the power supply filter capacitors.
Output capacitor (COUT)
1 µF
The regulator is stable without any output capacitance, but adding a 1-µF capacitor
improves the transient response.
Adjust capacitor (CADJ)
10 µF
A 10-µF capacitor bypassing the ADJUST pin to ground improves the regulators ripple
rejection.
Protection diode 1 (D1)
1N4002
Protection diode D1 is recommended if COUT is used. The diode provides a lowimpedance discharge path to prevent the capacitor from discharging into the output of the
regulator (see Protection Diodes).
Protection diode 2 (D2)
1N4002
Protection diode D2 is recommended if CADJ is used. The diode provides a low-impedance
discharge path to prevent the capacitor from discharging into the output of the regulator
(see Protection Diodes).
DESCRIPTION
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8.2.1.2 Detailed Design Procedure
8.2.1.2.1 External Capacitors
An input bypass capacitor is recommended. A 0.1-μF disc or 1-μF solid tantalum on the input is suitable input
bypassing for almost all applications. The device is more sensitive to the absence of input bypassing when
adjustment or output capacitors are used but the above values will eliminate the possibility of problems.
The adjustment terminal can be bypassed to ground on the LM138QML to improve ripple rejection. This bypass
capacitor prevents ripple from being amplified as the output voltage is increased. With a 10-μF bypass capacitor,
75-dB ripple rejection is obtainable at any output level. Increases over 20 μF do not appreciably improve the
ripple rejection at frequencies above 120 Hz. If the bypass capacitor is used, it is sometimes necessary to
include protection diodes to prevent the capacitor from discharging through internal low current paths and
damaging the device.
In general, the best type of capacitors to use are solid tantalum. Solid tantalum capacitors have low impedance
even at high frequencies. Depending upon capacitor construction, it takes about 25 μF in aluminum electrolytic to
equal 1-μF solid tantalum at high frequencies. Ceramic capacitors are also good at high frequencies; however,
some types have a large decrease in capacitance at frequencies around 0.5 MHz. For this reason, a 0.01-μF disc
may seem to work better than a 0.1-μF disc as a bypass.
Although the LM138QML is stable with no output capacitors, like any feedback circuit, certain values of external
capacitance can cause excessive ringing. This occurs with values between 500 pF and 5000 pF. A 1-μF solid
tantalum (or 25-μF aluminum electrolytic) on the output swamps this effect and insures stability.
8.2.1.2.2 Load Regulation
The LM138QML device is capable of providing extremely good load regulation but a few precautions are needed
to obtain maximum performance. The current set resistor connected between the adjustment terminal and the
output terminal (usually 240 Ω) should be tied directly to the output of the regulator (case) rather than near the
load; this eliminates line drops from appearing effectively in series with the reference and degrading regulation.
For example, a 15-V regulator with 0.05-Ω resistance between the regulator and load will have a load regulation
due to line resistance of 0.05 Ω × IL. If the set resistor is connected near the load the effective line resistance will
be 0.05 Ω (1 + R2/R1) or in this case, 11.5 times worse.
Figure 16 shows the effect of resistance between the regulator and 240-Ω set resistor.
LM138QML
RS
VIN
VIN
VOUT
ADJ
VOUT
R1*
240
R2
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Figure 16. Regulator With Line Resistance in Output Lead
With the TO-3 package, it is easy to minimize the resistance from the case to the set resistor by using two
separate leads to the case. The ground of R2 can be returned near the ground of the load to provide remote
ground sensing and improve load regulation.
8.2.1.2.3 Protection Diodes
When external capacitors are used with any IC regulator, it is sometimes necessary to add protection diodes to
prevent the capacitors from discharging through low current points into the regulator. Most 20-μF capacitors have
low enough internal series resistance to deliver 20-A spikes when shorted. Although the surge is short, there is
enough energy to damage parts of the IC.
14
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When an output capacitor is connected to a regulator and the input is shorted, the output capacitor discharges
into the output of the regulator. The discharge current depends on the value of the capacitor, the output voltage
of the regulator, and the rate of decrease of VIN. In the LM138QML, this discharge path is through a large
junction that is able to sustain 25-A surge with no problem; this is not true of other types of positive regulators.
For output capacitors of 100 μF or less at an output of 15 V or less, there is no need to use diodes.
The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs
when either the input or output is shorted. Internal to the LM138QML is a 50-Ω resistor which limits the peak
discharge current. No protection is needed for output voltages of 25-V or less and 10-μF capacitance. Figure 17
shows an LM138QML with protection diodes included for use with outputs greater than 25 V and high values of
output capacitance.
D1
1N4002
LM138QML
VIN
VIN
VOUT
VOUT
ADJ
+
R1
120
D2
1N4002
C1
+
R2
C2
10 µF
Copyright © 2017, Texas Instruments Incorporated
D1 protects against C1
D2 protects against C2
VOUT
R2 ·
§
1.25 V ¨ 1
R1 ¸¹
©
I ADJ R2
Figure 17. Regulator With Protection Diodes
8.2.1.3 Application Curves
Figure 18. Regulator Start-Up
Figure 19. Regulator Shutdown
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Figure 20. Regulator Response to Load Stop
16
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8.3 System Examples
LM138QML
VIN
VOUT
VIN
VOUT = 15 V
ADJ
R1
120
R2
1.4 k
VREF = 6.95 V
D1
LM329
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Figure 21. Regulator and Voltage Reference
LM138QML
VIN > 28 V
VOUT ‚‚
VOUT
VIN
ADJ
R1**
240
+
C1*
0.1 µF
C2‚
1 µF
R2**
5k
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Full output current not available at high input-output voltages
† Optional—improves transient response. Output capacitors in the range of 1 μF to 1000 μF of aluminum or tantalum
electrolytic are commonly used to provide improved output impedance and rejection of transients.
* Needed if device is more than 6 inches from filter capacitors.
‚‚ 9OUT
§
9¨
©
R2 ·
R1 ¸¹
, ADJ 5 2
** R1, R2 as an assembly can be ordered from Bourns:
MIL part no. 7105A-AT2-502
COMM part no. 7105A-AT7-502
Figure 22. 1.2-V to 25-V Adjustable Regulator
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System Examples (continued)
LM138QML
VIN
VOUT
OUT
IN
ADJ
R1
1.2 k
HEATER
LM334
100 k
GAIN
R2
80
Copyright © 2017, Texas Instruments Incorporated
Figure 23. Temperature Controller
LM138QML
VIN
OUT
IN
VOUT > 4 V
ADJ
1.2 k
IN457
LM336
R1
375
10 k*
IN457
R2
2k
OUTPUT
ADJUST
Copyright © 2017, Texas Instruments Incorporated
* Adjust for 3.75 V across R1
Figure 24. Precision Power Regulator With Low Temperature Coefficient
18
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System Examples (continued)
LM138QML
VIN
VOUT
15 V
VOUT
VIN
ADJ
R1
120
C2
0.1 µF
1N4002
R3
50 k
R2 2N2905
1.37 k
+
C1
100 µF
Copyright © 2017, Texas Instruments Incorporated
Figure 25. Slow Turnon 15-V Regulator
LM138QML
VIN
VIN
VOUT
ADJ
D1*
1N4002
R1
240
C2
0.1 µF
+
C3
1 —)‚
C1
10 µF
+
R2
5k
Copyright © 2017, Texas Instruments Incorporated
† Solid tantalum
* Discharges C1 if output is shorted to ground
Figure 26. Adjustable Regulator With Improved Ripple Rejection
LM138QML
VIN
15 V
VOUT
10 V
VOUT
VIN
ADJ
R1
2K
5%
C1
0.1 µF
R2
1.5 K
5%
R3
267
1%
Copyright © 2017, Texas Instruments Incorporated
Figure 27. High Stability 10-V Regulator
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System Examples (continued)
LM138QML
VIN
VOUT
VIN
VOUT
ADJ
R1
240
R2*
Inputs
Copyright © 2017, Texas Instruments Incorporated
* Sets maximum VOUT
Figure 28. Digitally Selected Outputs
R5
0.1
LM138QML
VIN
VOUT
ADJ
LM138QML
R1
0.05
VIN
VIN
R4
2k
R6
0.1
VOUT
ADJ
3
+
R3
2k
7
6
LM307
2
R2
0.1
-
4
LM138QML
VIN
VOUT
VOUT*
ADJ
R7*
120
C1
10 µF
+
+
C2
22 µF
R8
2k
Copyright © 2017, Texas Instruments Incorporated
* Minimum load—100 mA
Figure 29. 15-A Regulator
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System Examples (continued)
LM138QML
VIN
7 V ± 35 V
VIN
VOUT
5V
VOUT
ADJ
R1
120
C1
0.1 µF
C2
0.1 µF
R2
360 2N2219
TTL
1k
Copyright © 2017, Texas Instruments Incorporated
** Minimum output ≈ 1.2 V
Figure 30. 5-V Logic Regulator With Electronic Shutdown**
LM138QML
VIN
OUT
IN
ADJ
2k
Copyright © 2017, Texas Instruments Incorporated
Figure 31. Light Controller
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System Examples (continued)
LM138QML
VIN
25 V
VIN
VOUT
VOUT
ADJ
R1
240
C1
0.1 µF
R2
5k
LM113
1.2 V
R3
680
±10 V
Copyright © 2017, Texas Instruments Incorporated
Full output current not available at high input-output voltages
Figure 32. 0-V to 22-V Regulator
500
R6
0.2
LM138QML
VIN > 18 V
+
R2
15
LED
R5
1k
R3
230
R4
15 k
Q1
2N2905
R1
3k
0.1 µF
7
1
1N457
+
TO 12 V
BATTERY
LM301A
-
8
2
4
+
1 µF
1000 pF
START
-
Copyright © 2017, Texas Instruments Incorporated
Figure 33. 12-V Battery Charger
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System Examples (continued)
LM138QML
VIN
VIN
R1
0.24
IOUT
0A±5A
VOUT
ADJ
R2
150
VIN
ADJ
LM117
VOUT
R3
120
V±
±5 V TO ±10 V
Copyright © 2017, Texas Instruments Incorporated
Figure 34. Adjustable Current Regulator
LM138QML
VIN
IOUT =
VOUT
VIN
ADJ
R1
VREF
R1
Copyright © 2017, Texas Instruments Incorporated
Figure 35. Precision Current Limiter
LM138QML
VIN
VIN
VOUT
ADJ
C1
0.1 µF
R1
0.24 Ÿ
2W
LOAD
Copyright © 2017, Texas Instruments Incorporated
Figure 36. 5-A Current Regulator
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System Examples (continued)
R2
720
R1
240
LM138QML
ADJ
VIN
VOUT
VIN
VOUT
VIN
VOUT
ADJ
LM138QML
R3
120
+
C2
0.1 µF
C2
1 µF
R4
1k
OUTPUT
ADJUST
Copyright © 2017, Texas Instruments Incorporated
Figure 37. Tracking Preregulator
LM138QML
VIN
VOUT
VIN
VOUT
ADJ
VIN
VOUT
VIN
VOUT ‚
ADJ
1N4002
R1
120
VIN
VOUT
VIN
VOUT ‚
ADJ
1N4002
1N4002
R2
1k
Copyright © 2017, Texas Instruments Incorporated
† Minimum load—10 mA
* All outputs within ±100 mV
Figure 38. Adjusting Multiple On-Card Regulators With Single Control*
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System Examples (continued)
35 V
22
100 k
MJ4502
RF
+
10 k
2
-
IN
LF351
+
3
CF
75 pF
6
5k
7
20 pF
4
1000 µF
LM395
+
RL > 4
1 µF
100 k
INPUT
ADJ
LM138QML
OUT
0.1 µF
0.4
Copyright © 2017, Texas Instruments Incorporated
AV = 1, RF = 10k, CF = 100 pF
AV = 10, RF = 100k, CF = 10 pF
Bandwidth ≥ 100 kHz
Distortion ≤ 0.1%
Figure 39. Power Amplifier
LM138QML
VIN
RS*
0.1
VOUT
VIN
ADJ
R1
240
+
12 V
1000 µF**
R2
2.4 k
Copyright © 2017, Texas Instruments Incorporated
Z OUT
§ R2 ·
R S ¨1
¸
R1 ¹
©
* RS sets output impedance of charger
Use of RS allows low charging rates with fully charged battery.
** The 1000 μF is recommended to filter out input transients
Figure 40. Simple 12-V Battery Charger
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System Examples (continued)
0.1
VIN
LM138QML
0.1
LM138QML
LM138QML
0.1
VIN
VOUT
4.5 V to 25 V
ADJ
100
5k
2N2905
7
2
6
LM308
8
+
3
150
5k
1.5 k
200 pF
4
Copyright © 2017, Texas Instruments Incorporated
Figure 41. Adjustable 15-A Regulator
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System Examples (continued)
LM138QML
VIN
9 V to 30 V
VOUT
VIN
ADJ
240
+
+
1000 µF**
1.1 k
100
2N2222
0.2*
Copyright © 2017, Texas Instruments Incorporated
* Set max charge current to 3 A
** The 1000 μF is recommended to filter out input transients.
Figure 42. Current Limited 6-V Charger
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System Examples (continued)
R
0.1
LM138QML
VIN
VOUT
ADJ
3
+
LM107
2
R
0.1
-
R3
2k
7
6
4
LM138QML
VIN
VIN
OUTPUT*
1.2 V to 20 V
VOUT
ADJ
R1
120
C1
1 µF
+
R2
2k
Copyright © 2017, Texas Instruments Incorporated
* Minimum load—100 mA
Figure 43. 10-A Regulator
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9 Power Supply Recommendations
The input supply to LM138QML must be kept at a voltage level such that its maximum input to output differential
voltage rating is not exceeded. The minimum dropout voltage must also be met with extra headroom when
possible to keep the LM138QML in regulation. TI recommends a capacitor be placed at the input to bypass
noise.
10 Layout
10.1 Layout Guidelines
Some layout guidelines must be followed to ensure proper regulation of the output voltage with minimum noise.
Traces carrying the load current must be wide to reduce the amount of parasitic trace inductance and the
feedback loop from VOUT to ADJ must be kept as short as possible. To improve PSRR, a bypass capacitor can
be placed at the ADJ pin and must be placed as close as possible to the device. In cases when VIN shorts to
ground, an external diode must be placed from VOUT to VIN to divert the surge current from the output capacitor
and protect the deice. Similarly, in cases when a large bypass capacitor is placed at the ADJ pin and VOUT shorts
to ground, an external diode must be placed from ADJ to VOUT to provide a path for the bypass capacitor to
discharge. These diodes must be placed close to the corresponding device pins to increase their effectiveness.
10.2 Layout Example
Figure 44. LM138QML Layout
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11 Device and Documentation Support
11.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge Caution
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.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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26-Apr-2018
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
LM138K-MIL
ACTIVE
TO
K
2
50
TBD
Call TI
Call TI
LM138KG-MD8
ACTIVE
DIESALE
Y
0
100
Green (RoHS
& no Sb/Br)
Call TI
Level-1-NA-UNLIM
Op Temp (°C)
Device Marking
(4/5)
LM138K-MIL
ACO
>T
-55 to 125
(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
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 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
26-Apr-2018
Addendum-Page 2
MECHANICAL DATA
K0002C
K02C (Rev E)
4214774/A 03/2013
NOTES:
1. All linear dimensions are in millimeters. Dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. Leads not to be bent greater than 15º
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IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
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