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LM317
SLVS044Y – SEPTEMBER 1997 – REVISED APRIL 2020

LM317 3-Terminal Adjustable Regulator

1 Features 3 Description
1• Output voltage range adjustable The LM317 device is an adjustable three-terminal
from 1.25 V to 37 V positive-voltage regulator capable of supplying more
than 1.5 A over an output-voltage range of 1.25 V to
• Output current greater than 1.5 A 37 V. It requires only two external resistors to set the
• Internal short-circuit current limiting output voltage. The device features a typical line
• Thermal overload protection regulation of 0.01% and typical load regulation of
0.1%. It includes current limiting, thermal overload
• Output safe-area compensation
protection, and safe operating area protection.
Overload protection remains functional even if the
2 Applications ADJUST terminal is disconnected.
• ATCA solutions
Device Information(1)
• DLP: 3D biometrics, hyperspectral imaging,
PART NUMBER PACKAGE BODY SIZE (NOM)
optical networking, and spectroscopy
LM317DCY SOT-223 (4) 6.50 mm × 3.50 mm
• DVR and DVS
LM317KCS TO-220 (3) 10.16 mm × 9.15 mm
• Desktop PCs
LM317KCT TO-220 (3) 10.16 mm × 8.59 mm
• Digital signage and still cameras
LM317KTT TO-263 (3) 10.16 mm × 9.01 mm
• ECG electrocardiograms
(1) For all available packages, see the orderable addendum at
• EV HEV chargers: levels 1, 2, and 3 the end of the data sheet.
• Electronic shelf labels
• Energy harvesting Battery-Charger Circuit
• Ethernet switches RS
LM317 0.2 W
• Femto base stations VI INPUT OUTPUT
• Fingerprint and iris biometrics
ADJUST R1
• HVAC: heating, ventilating, and air conditioning 240 W
• High-speed data acquisition and generation
• Hydraulic valves
R2
• IP phones: wired and wireless 2.4 kW
• Intelligent occupancy sensing
• Motor controls: brushed DC, brushless DC, low-
voltage, permanent magnet, and stepper motors
• Point-to-point microwave backhauls
• Power bank solutions
• Power line communication modems
• Power over ethernet (PoE)
• Power quality meters
• Power substation controls
• Private branch exchanges (PBX)
• Programmable logic controllers
• RFID readers
• Refrigerators
• Signal or waveform generators
• Software-defined radios (SDR)
• Washing machines: high-end and low-end
• X-rays: baggage scanners, medical, and dental

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 Features .................................................................. 1 8.4 Device Functional Modes........................................ 10
2 Applications ........................................................... 1 9 Application and Implementation ........................ 11
3 Description ............................................................. 1 9.1 Application Information............................................ 11
4 Revision History..................................................... 2 9.2 Typical Application .................................................. 11
9.3 System Examples ................................................... 12
5 Device Comparison Table..................................... 3
6 Pin Configuration and Functions ......................... 4 10 Power Supply Recommendations ..................... 18
7 Specifications......................................................... 5 11 Layout................................................................... 18
11.1 Layout Guidelines ................................................. 18
7.1 Absolute Maximum Ratings ...................................... 5
11.2 Layout Example .................................................... 18
7.2 ESD Ratings.............................................................. 5
7.3 Recommended Operating Conditions....................... 5 12 Device and Documentation Support ................. 19
7.4 Thermal Information .................................................. 5 12.1 Receiving Notification of Documentation Updates 19
7.5 Electrical Characteristics........................................... 6 12.2 Support Resources ............................................... 19
7.6 Typical Characteristics .............................................. 7 12.3 Trademarks ........................................................... 19
12.4 Electrostatic Discharge Caution ............................ 19
8 Detailed Description .............................................. 9
12.5 Glossary ................................................................ 19
8.1 Overview ................................................................... 9
8.2 Functional Block Diagram ......................................... 9 13 Mechanical, Packaging, and Orderable
8.3 Feature Description................................................... 9
Information ........................................................... 19

4 Revision History
Changes from Revision X (September 2016) to Revision Y Page

• Added Device Comparison Table .......................................................................................................................................... 3

• Changed VIN to IOUT in Load Transient Response figures ...................................................................................................... 7
• Added missing caption to second y-axis in second Load Transient Response figure ........................................................... 7
• Changed VOUT and output impedance equations in Battery-Charger Circuit section........................................................... 14

Changes from Revision W (January 2015) to Revision X Page

• Changed body size dimensions for KCS TO-220 Package on Device information table ...................................................... 1
• Changed body size dimensions for KTT TO-263 Package on Device information table ...................................................... 1
• Changed VO Output Voltage max value from 7 to 37 on Recommended Operating Conditions table .................................. 5
• Added min value to IO Output Current in Recommended Operating Conditions table .......................................................... 5
• Changed values in the Thermal Information table to align with JEDEC standards ............................................................... 5
• Added KCT package data to Thermal Information table ....................................................................................................... 5
• Deleted Section 9.3.6 "Adjusting Multiple On-Card Regulators with a Single Control" ....................................................... 14
• Updated Adjustsable 4-A Regulator Circuit graphic ............................................................................................................ 16
• Added Receiving Notification of Documentation Updates section and Community Resources section .............................. 19

Changes from Revision V (February 2013) to Revision W Page

• Added Applications, Device Information table, Pin Functions table, ESD Ratings table, Thermal Information table,
Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply
Recommendations section, Layout section, Device and Documentation Support section, and Mechanical,
Packaging, and Orderable Information section. ..................................................................................................................... 1
• Deleted Ordering Information table. ....................................................................................................................................... 1

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5 Device Comparison Table

IOUT PARAMETER LM317 LM317-N LM317A LM317HV UNIT

Input voltage range 4.25 - 40 4.25 - 40 4.25 - 40 4.25 - 60 V
Load regulation accuracy 1.5 1.5 1 1.5 %
PSRR (120 Hz) 64 80 80 65 dB
Recommended operating temperature 0 to 125 0 to 125 –40 to 125 0 to 125 °C
TO-220 (NDE) TJA 23.5 23.2 23.3 23 °C/W
1.5 A
TO-200 (KCT) TJA 37.9 N/A N/A °C/W
TO-252 TJA N/A 54 54 °C/W
TO-263 TJA 38 41 N/A °C/W
SOT-223 TJA 66.8 59.6 59.6 °C/W
TO-92 TJA N/A 186 186 °C/W
LM317M
Input voltage range 3.75 - 40 V
Load regulation accuracy 1.5 %
0.5 A PSRR (120 Hz) 80 dB
Recommended operating temperature -40 - 125 °C
SOT-223 TJA 60.2 °C/W
TO-252 TJA 56.9 °C/W
LM317L LM317L-N
Input voltage range 3.75 - 40 4.25 - 40 V
Load regulation accuracy 1 1.5 %
PSRR (120 Hz) 62 80 dB
0.1 A Recommended operating temperature –40 to 125 –40 to 125 °C
SOT-23 TJA 167.8 N/A °C/W
SO-8 TJA N/A 165 °C/W
DSBGA TJA N/A 290 °C/W
TO-92 TJA N/A 180 °C/W

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6 Pin Configuration and Functions

DCY Package KCS or KCT Package

3-Pin SOT-223 3-Pin TO-220
Top View Top View

3 INPUT

OUTPUT
ADJUST 1 2 OUTPUT

OUTPUT 2 4 OUTPUT 1 ADJUST

INPUT 3 Not to scale

Not to scale

KTT Package
3-Pin TO-263
Top View

3 INPUT
OUTPUT

2 OUTPUT

1 ADJUST

Not to scale

Pin Functions
PIN
TO-263, I/O DESCRIPTION
NAME SOT-223
TO-220
ADJUST 1 1 I Output voltage adjustment pin. Connect to a resistor divider to set VO
INPUT 3 3 I Supply input pin
OUTPUT 2 2, 4 O Voltage output pin

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7 Specifications
7.1 Absolute Maximum Ratings
over virtual junction temperature range (unless otherwise noted) (1)
MIN MAX UNIT
VI – VO Input-to-output differential voltage 40 V
TJ Operating virtual junction temperature 150 °C
Lead temperature 1,6 mm (1/16 in) from case for 10 s 260 °C
Tstg Storage temperature –65 150 °C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating
Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

7.2 ESD Ratings

MAX UNIT
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) 2500
V(ESD) Electrostatic discharge V
Charged device model (CDM), per JEDEC specification JESD22-C101 (2) 1000

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

MIN MAX UNIT
VO Output voltage 1.25 37 V
VI – VO Input-to-output differential voltage 3 40 V
IO Output current 0.01 1.5 A
TJ Operating virtual junction temperature 0 125 °C

7.4 Thermal Information

LM317
DCY KCS KCT KTT
THERMAL METRIC (1) UNIT
(SOT-223) (TO-220) (TO-220) (TO-263)
4 PINS 3 PINS 3 PINS 3 PINS
Rθ(JA) Junction-to-ambient thermal resistance 66.8 23.5 37.9 38.0 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 43.2 15.9 51.1 36.5 °C/W
RθJB Junction-to-board thermal resistance 16.9 7.9 23.2 18.9 °C/W
ψJT Junction-to-top characterization parameter 3.6 3.0 13.0 6.9 °C/W
ψJB Junction-to-board characterization parameter 16.8 7.8 22.8 17.9 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance NA 0.1 4.2 1.1 °C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC package thermal metrics application
report.

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7.5 Electrical Characteristics

over recommended ranges of operating virtual junction temperature (unless otherwise noted)
PARAMETER TEST CONDITIONS (1) MIN TYP MAX UNIT
TJ = 25°C 0.01 0.04
Line regulation (2) VI – VO = 3 V to 40 V %/V
TJ = 0°C to 125°C 0.02 0.07
CADJ (3) = 10 μF, VO ≤ 5 V 25 mV
TJ = 25°C VO ≥ 5 V 0.1 0.5 %VO
Load regulation IO = 10 mA to 1500 mA
VO ≤ 5 V 20 70 mV
TJ = 0°C to 125°C
VO ≥ 5 V 0.3 1.5 %VO
Thermal regulation 20-ms pulse, TJ = 25°C 0.03 0.07 %VO/W
ADJUST terminal current 50 100 μA
Change in
VI – VO = 2.5 V to 40 V, PD ≤ 20 W, IO = 10 mA to 1500 mA 0.2 5 μA
ADJUST terminal current
Reference voltage VI – VO = 3 V to 40 V, PD ≤ 20 W, IO = 10 mA to 1500 mA 1.2 1.25 1.3 V
Output-voltage
TJ = 0°C to 125°C 0.7 %VO
temperature stability
Minimum load current
VI – VO = 40 V 3.5 10 mA
to maintain regulation
VI – VO ≤ 15 V, PD < PMAX (4) 1.5 2.2
Maximum output current A
VI – VO ≤ 40 V, PD < PMAX (4), TJ = 25°C 0.15 0.4
RMS output noise voltage
f = 10 Hz to 10 kHz, TJ = 25°C 0.003 %VO
(% of VO)
(3)
CADJ = 0 μF 57
Ripple rejection VO = 10 V, f = 120 Hz dB
CADJ = 10 μF (3) 62 64
Long-term stability TJ = 25°C 0.3 1 %/1k hr

(1) Unless otherwise noted, the following test conditions apply: |VI – VO| = 5 V and IOMAX = 1.5 A, TJ = 0°C to 125°C. Pulse testing
techniques are used to maintain the junction temperature as close to the ambient temperature as possible.
(2) Line regulation is expressed here as the percentage change in output voltage per 1-V change at the input.
(3) CADJ is connected between the ADJUST terminal and GND.
(4) Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient
temperature is PD = (TJ(max) – TA) / θJA. Operating at the absolute maximum TJ of 150°C can affect reliability.

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7.6 Typical Characteristics

10.01 1.4
TA = 25°C
TA = –40°C 1.2
10.005 TA = –40°C
1

10 0.8
TA = 25°C
V OUT – V

V OUT – V
0.6
9.995
0.4
TA = 125°C TA = 125°C
9.99 0.2

0
9.985
-0.2
VOUT = 10 V Nom VOUT = VREF
9.98 -0.4

0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5

IOUT – A IOUT – A

Figure 1. Load Regulation Figure 2. Load Regulation

0 11 0 11

-0.5 10.8 -0.5 10.8

-1 10.6 -1 10.6
IOUT IOUT
-1.5 10.4 -1.5 10.4

VOUT Deviation ̶ V
V OUT Deviation – V
Load Current – A

Load Current – A

-2 10.2 -2 10.2
VOUT VOUT
-2.5 10 -2.5 10

-3 9.8 -3 9.8

-3.5 9.6 -3.5 9.6

-4 9.4 -4 9.4

-4.5 9.2 -4.5 9.2

CADJ = 0 µF CADJ = 10 µF
-5 9 -5 9
-30
-20
-10
0
10
20
30
40
50
60
70

-30

-20

-10

10

20

30

40

50

60

70
Tim e – µs Tim e – µs

Figure 3. Load Transient Response Figure 4. Load Transient Response

1.285 -68

1.28 -66

1.275 -64
Ripple Rejection – dB

1.27 -62
TA = –40°C
V OUT – V

1.265 -60
TA = 25°C
1.26 -58

1.255 TA = 125°C -56

V IN = 15 V
1.25 -54
V OUT = 10 V
f = 120 Hz
1.245 -52
TA = 25°C
1.24 -50
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
0

10

15

20

25

30

35

40

V IN – V IOUT – A

Figure 5. Line Regulation Figure 6. Ripple Rejection

vs Output Current

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Typical Characteristics (continued)

-75 -90
V IN = 15 V
V OUT = 10 V
-70 -80
IOUT = 500 m A CADJ = 0 µF
TA = 25°C
-65 -70
Ripple Rejection – dB

Ripple Rejection – dB
-60 -60

-55 -50 CADJ = 10 µF

-50 -40

-45 V IN – V OUT = 15 V -30

IOUT = 500 m A
-40 f = 120 Hz -20
TA = 25°C
-35 -10
5 10 15 20 25 30 35 100
100 1k
1000 10k
10000 100k
100000 1M
1000000
V OUT – V Frequency – Hz

Figure 7. Ripple Rejection Figure 8. Ripple Rejection

vs Output Voltage vs Frequency

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8 Detailed Description

8.1 Overview
The LM317 device is an adjustable three-terminal positive-voltage regulator capable of supplying up to 1.5 A
over an output-voltage range of 1.25 V to 37 V. It requires only two external resistors to set the output voltage.
The device features a typical line regulation of 0.01% and typical load regulation of 0.1%. It includes current
limiting, thermal overload protection, and safe operating area protection. Overload protection remains functional
even if the ADJUST terminal is disconnected.
The LM317 device is versatile in its 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 LM317
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.

8.2 Functional Block Diagram

Input

Iadj

1.25 V
Over Temp &
Over Current
Protection
Adj.

Output

8.3 Feature Description

8.3.1 NPN Darlington Output Drive
NPN Darlington output topology provides naturally low output impedance and an output capacitor is optional. 3-V
headroom is recommended (VI – VO) to support maximum current and lowest temperature.

8.3.2 Overload Block

Over-current and over-temperature shutdown protects the device against overload or damage from operating in
excessive heat.

8.3.3 Programmable Feedback

Op amp with 1.25-V offset input at the ADJUST terminal provides easy output voltage or current (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 V)2/R should be used. For voltage regulation applications, two resistors set the output
voltage.

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8.4 Device Functional Modes

8.4.1 Normal Operation
The device OUTPUT pin will source current necessary to make OUTPUT pin 1.25 V greater than ADJUST
terminal to provide output regulation.

8.4.2 Operation With Low Input Voltage

The device requires up to 3-V headroom (VI – VO) to operate in regulation. The device may drop out and
OUTPUT voltage will be INPUT voltage minus drop out voltage with less headroom.

8.4.3 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. See the Electrical Characteristics table for the minimum load
current needed to maintain regulation.

8.4.4 Operation In Self Protection

When an overload occurs the device shuts down Darlington NPN output stage or reduces the output current to
prevent device damage. The device will automatically reset from the overload. The output may be reduced or
alternate between on and off until the overload is removed.

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9 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.

9.1 Application Information

The flexibility of the LM317 allows it to be configured to take on many different functions in DC power
applications.

9.2 Typical Application

D1
1N4002

Input Output
VI LM317 VO

Adjust R1
240 W
D2
Vref = 1.25 V 1N4002
IAdj
Ci CO
0.1 µF 1.0 µF

R2 CADJ

Figure 9. Adjustable Voltage Regulator

9.2.1 Design Requirements

• R1 and R2 are required to set the output voltage.
• CADJ is recommended to improve ripple rejection. It prevents amplification of the ripple as the output voltage
is adjusted higher.
• Ci is recommended, particularly if the regulator is not in close proximity to the power-supply filter capacitors. A
0.1-µF or 1-µF ceramic or tantalum capacitor provides sufficient bypassing for most applications, especially
when adjustment and output capacitors are used.
• CO improves transient response, but is not needed for stability.
• 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.
• Protection diode D1 is recommended if CO is used. The diode provides a low-impedance discharge path to
prevent the capacitor from discharging into the output of the regulator.

9.2.2 Detailed Design Procedure

VO is calculated as shown in Equation 1. IADJ is typically 50 µA and negligible in most applications.
VO = VREF (1 + R2 / R1) + (IADJ × R2) (1)

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Typical Application (continued)

9.2.3 Application Curves

20 10.10 20 10.12
CADJ = 0 µF CADJ = 10 µF
19 10.08 10.10
VOUT 19

VOUT 10.08
18 10.06 18
V IN Change – V

V IN Change – V
10.06

V OUT – V

V OUT – V
17 10.04 17
10.04
VIN VIN
16 10.02 16
10.02

15 10.00 15
10.00

14 9.98 14 9.98
-25

-15

-5

15

25

35

45

55

65

-25

-15

-5

15

25

35

45

55

65
Tim e – µs Tim e – µs

Figure 10. Line-Transient Response Figure 11. Line-Transient Response

9.3 System Examples

9.3.1 0-V to 30-V Regulator Circuit
æ R + R3 ö
VOUT = VREF ç 1 + 2 ÷ - 10 V
Here, the voltage is determined by è R1 ø

LM317
+35 V INPUT OUTPUT VO

ADJUST R1
120 W

−10 V
C1 R2
0.1 µF R3 3 kW
680 W

Figure 12. 0-V to 30-V Regulator Circuit

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System Examples (continued)

9.3.2 Adjustable Regulator Circuit With Improved Ripple Rejection
C2 helps to stabilize the voltage at the adjustment pin, which helps reject noise. Diode D1 exists to discharge C2
in case the output is shorted to ground.

LM317
VI INPUT OUTPUT VO

ADJUST D1
R1
1N4002
240 W

C1 C3
0.1 µF 1 µF

R2 C2
5 kW 10 µF

Figure 13. Adjustable Regulator Circuit with Improved Ripple Rejection

9.3.3 Precision Current-Limiter Circuit

This application limits the output current to the ILIMIT in the diagram.

LM317
VI Ilimit 1.2
INPUT OUTPUT
R1
R1
ADJUST

Figure 14. Precision Current-Limiter Circuit

9.3.4 Tracking Preregulator Circuit

This application keeps a constant voltage across the second LM317 in the circuit.
R2
720 Ω

R1
240 Ω
ADJUST
VI INPUT OUTPUT
LM317 LM317
INPUT OUTPUT VO

ADJUST R3
120 Ω
C1
0.1 µF C2
1 µF
Output R4
Adjust 1 kΩ

Figure 15. Tracking Preregulator Circuit

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System Examples (continued)

9.3.5 1.25-V to 20-V Regulator Circuit With Minimum Program Current
Because the value of VREF is constant, the value of R1 determines the amount of current that flows through R1
and R2. The size of R2 determines the IR drop from ADJUSTMENT to GND. Higher values of R2 translate to
higher VOUT.
æ R + R3 ö
VOUT = VREF ç 1 + 2 ÷ - 10 V
è R1 ø (2)
(R1 + R2 )min = VoIreg(min) (3)

LM317
VI INPUT OUTPUT VO

ADJUST
R1
1.2 kΩ

R2
20 kΩ

Figure 16. 1.25-V to 20-V Regulator Circuit With Minimum Program Current

9.3.6 Battery-Charger Circuit

The series resistor limits the current output of the LM317, minimizing damage to the battery cell.
§ R2 ·
V OUT 1.25 V u ¨ 1
© R1 ¸¹ (4)
1.25V
IOUT(short) =
RS (5)
§ R2 ·
Output Impedance RS u ¨1
© R1 ¸¹ (6)
RS
LM317 0.2 W
VI INPUT OUTPUT

ADJUST R1
240 W

R2
2.4 kW

Figure 17. Battery-Charger Circuit

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System Examples (continued)

9.3.7 50-mA Constant-Current Battery-Charger Circuit
The current limit operation mode can be used to trickle charge a battery at a fixed current. ICHG = 1.25 V ÷ 24 Ω.
VI should be greater than VBAT + 4.25 V. (1.25 V [VREF] + 3 V [headroom])

LM317
24 Ω
VI INPUT OUTPUT

ADJUST

Figure 18. 50-mA Constant-Current Battery-Charger Circuit

9.3.8 Slow Turn-On 15-V Regulator Circuit

The capacitor C1, in combination with the PNP transistor, helps the circuit to slowly start supplying voltage. In the
beginning, the capacitor is not charged. Therefore output voltage starts at VC1+ VBE + 1.25 V = 0 V + 0.65 V +
1.25 V = 1.9 V. As the capacitor voltage rises, VOUT rises at the same rate. When the output voltage reaches the
value determined by R1 and R2, the PNP will be turned off.

LM317
VI INPUT OUTPUT VO = 15 V

ADJUST R1 D1
240 Ω 1N4002

R3
50 kΩ
R2
2.7 kΩ
2N2905 C1
25 µF

Figure 19. Slow Turn-On 15-V Regulator Circuit

9.3.9 AC Voltage-Regulator Circuit

These two LM317s can regulate both the positive and negative swings of a sinusoidal AC input.

LM317
VI INPUT OUTPUT

ADJUST 480 Ω 120 Ω

12 VI(PP) 6 VO(PP)
480 Ω
2 W (TYP)
120 Ω
ADJUST
VI INPUT OUTPUT

LM317

Figure 20. AC Voltage-Regulator Circuit

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System Examples (continued)

9.3.10 Current-Limited 6-V Charger Circuit
As the charge current increases, the voltage at the bottom resistor increases until the NPN starts sinking current
from the adjustment pin. The voltage at the adjustment pin drops, and consequently the output voltage
decreases until the NPN stops conducting.

LM317
VI+ INPUT OUTPUT

ADJUST R1
240 W

R2
1.1 kW

R3

VI−

Figure 21. Current-Limited 6-V Charger Circuit

9.3.11 Adjustable 4-A Regulator Circuit

This application keeps the output current at 4 A while having the ability to adjust the output voltage using the
adjustable (1.5 kΩ in schematic) resistor.

LM317
0.2 Ω
VI INPUT OUTPUT

ADJUST

LM317
0.2 Ω
INPUT OUTPUT

ADJUST

4.5 V to 25 V

LM317
0.2 Ω
INPUT OUTPUT

ADJUST
5 kΩ

100 Ω 5 kΩ
_

TL084 150 Ω
2N2905 +
200 pF

1.5 k Ω

Figure 22. Adjustable 4-A Regulator Circuit

16 Submit Documentation Feedback Copyright © 1997–2020, Texas Instruments Incorporated

Product Folder Links: LM317

 LM317
www.ti.com SLVS044Y – SEPTEMBER 1997 – REVISED APRIL 2020

System Examples (continued)

9.3.12 High-Current Adjustable Regulator Circuit
The NPNs at the top of the schematic allow higher currents at VOUT than the LM317 can provide, while still
keeping the output voltage at levels determined by the adjustment pin resistor divider of the LM317.
TIP73

2N2905
500 W

VI
5 kW

LM317
22 W
INPUT OUTPUT VO

ADJUST
120 W 1N4002

10 µF 47 µF
10 µF

Figure 23. High-Current Adjustable Regulator Circuit

Copyright © 1997–2020, Texas Instruments Incorporated Submit Documentation Feedback 17

Product Folder Links: LM317
LM317
SLVS044Y – SEPTEMBER 1997 – REVISED APRIL 2020 www.ti.com

10 Power Supply Recommendations

The LM317 is designed to operate from an input voltage supply range between 1.25 V to 37 V greater than the
output voltage. If the device is more than six inches from the input filter capacitors, an input bypass capacitor, 0.1
μF or greater, of any type is needed for stability.

11 Layout

11.1 Layout Guidelines

• TI recommends that the input terminal be bypassed to ground with a bypass capacitor.
• The optimum placement is closest to the input terminal of the device and the system GND. Take care to
minimize the loop area formed by the bypass-capacitor connection, the input terminal, and the system GND.
• For operation at full rated load, TI recommends to use wide trace lengths to eliminate I × R drop and heat
dissipation.

11.2 Layout Example

COUT OUTPUT
Ground

R2
Power
OUTPUT
ADJ/GND

INPUT

High
High Input
Frequency
Bypass
Bypass
Capacitor 0.1μF 10μF Capacitor
Cadj R1
Ground

Figure 24. Layout Example

18 Submit Documentation Feedback Copyright © 1997–2020, Texas Instruments Incorporated

Product Folder Links: LM317

 LM317
www.ti.com SLVS044Y – SEPTEMBER 1997 – REVISED APRIL 2020

12 Device and Documentation Support

12.1 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.

12.2 Support Resources

TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is 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.

12.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments 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.

12.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.

13 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.

Copyright © 1997–2020, Texas Instruments Incorporated Submit Documentation Feedback 19

Product Folder Links: LM317
 PACKAGE OPTION ADDENDUM

www.ti.com 18-Oct-2023

PACKAGING INFORMATION

Orderable Device Status Package Type Package Pins Package Eco Plan Lead finish/ MSL Peak Temp Op Temp (°C) Device Marking Samples
(1) Drawing Qty (2) Ball material (3) (4/5)
(6)

LM317DCY ACTIVE SOT-223 DCY 4 80 RoHS & Green SN Level-2-260C-1 YEAR 0 to 125 L3 Samples

LM317DCYG3 ACTIVE SOT-223 DCY 4 80 RoHS & Green SN Level-2-260C-1 YEAR 0 to 125 L3 Samples

LM317DCYR ACTIVE SOT-223 DCY 4 2500 RoHS & Green SN Level-2-260C-1 YEAR 0 to 125 L3 Samples

LM317DCYRG3 ACTIVE SOT-223 DCY 4 2500 RoHS & Green SN Level-2-260C-1 YEAR 0 to 125 L3 Samples

LM317KCS LIFEBUY TO-220 KCS 3 50 RoHS & Green SN N / A for Pkg Type 0 to 125 LM317
LM317KCSE3 LIFEBUY TO-220 KCS 3 50 RoHS & Green SN N / A for Pkg Type 0 to 125 LM317
LM317KTTR ACTIVE DDPAK/ KTT 3 500 RoHS & Green SN Level-3-245C-168 HR 0 to 125 LM317 Samples
TO-263
LM317KTTRG3 ACTIVE DDPAK/ KTT 3 500 RoHS & Green SN Level-3-245C-168 HR 0 to 125 LM317 Samples
TO-263

(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.

Addendum-Page 1
 PACKAGE OPTION ADDENDUM

www.ti.com 18-Oct-2023

(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material 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 2
 PACKAGE MATERIALS INFORMATION

www.ti.com 27-Sep-2023

TAPE AND REEL INFORMATION

REEL DIMENSIONS TAPE DIMENSIONS

K0 P1

B0 W
Reel
Diameter
Cavity A0
A0 Dimension designed to accommodate the component width
B0 Dimension designed to accommodate the component length
K0 Dimension designed to accommodate the component thickness
W Overall width of the carrier tape
P1 Pitch between successive cavity centers

Reel Width (W1)

QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE

Sprocket Holes

Q1 Q2 Q1 Q2

Q3 Q4 Q3 Q4 User Direction of Feed

Pocket Quadrants

*All dimensions are nominal

Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1
Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
LM317DCYR SOT-223 DCY 4 2500 330.0 12.4 7.05 7.4 1.9 8.0 12.0 Q3
LM317DCYR SOT-223 DCY 4 2500 330.0 12.4 6.55 7.25 1.9 8.0 12.0 Q3
LM317KTTR DDPAK/ KTT 3 500 330.0 24.4 10.8 16.1 4.9 16.0 24.0 Q2
TO-263
LM317KTTR DDPAK/ KTT 3 500 330.0 24.4 10.8 16.3 5.11 16.0 24.0 Q2
TO-263

Pack Materials-Page 1
 PACKAGE MATERIALS INFORMATION

www.ti.com 27-Sep-2023

TAPE AND REEL BOX DIMENSIONS

Width (mm)
H
W

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
LM317DCYR SOT-223 DCY 4 2500 340.0 340.0 38.0
LM317DCYR SOT-223 DCY 4 2500 336.0 336.0 48.0
LM317KTTR DDPAK/TO-263 KTT 3 500 350.0 334.0 47.0
LM317KTTR DDPAK/TO-263 KTT 3 500 340.0 340.0 38.0

Pack Materials-Page 2
 PACKAGE MATERIALS INFORMATION

www.ti.com 27-Sep-2023

TUBE

T - Tube
height L - Tube length

W - Tube
width

B - Alignment groove width

*All dimensions are nominal

Device Package Name Package Type Pins SPQ L (mm) W (mm) T (µm) B (mm)
LM317DCY DCY SOT-223 4 80 559 8.6 500 3.6
LM317DCY DCY SOT-223 4 80 542.9 8.6 3606 2.67
LM317DCYG3 DCY SOT-223 4 80 559 8.6 500 3.6
LM317DCYG3 DCY SOT-223 4 80 542.9 8.6 3606 2.67
LM317KCS KCS TO-220 3 50 532 34.1 700 9.6
LM317KCS KCS TO-220 3 50 532 34.1 700 9.6
LM317KCSE3 KCS TO-220 3 50 532 34.1 700 9.6
LM317KCSE3 KCS TO-220 3 50 532 34.1 700 9.6

Pack Materials-Page 3
 PACKAGE OUTLINE
KCS0003B SCALE 0.850
TO-220 - 19.65 mm max height
TO-220

4.7
4.4
10.36 1.32
2.9 1.22 8.55
9.96
2.6 8.15

6.5
(6.3)
6.1
( 3.84) 12.5
12.1

19.65 MAX
9.25
9.05

3X
3.9 MAX

13.12
12.70

1 3

0.90 0.47
3X 0.34
0.77
2.79
2X 2.54
2.59
1.36
3X
1.23
5.08

4222214/B 08/2018

NOTES:

1. Dimensions are in millimeters. Any dimension in brackets or parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. Reference JEDEC registration TO-220.

www.ti.com
 EXAMPLE BOARD LAYOUT
KCS0003B TO-220 - 19.65 mm max height
TO-220

0.07 MAX 2X (1.7)

ALL AROUND 3X (1.2) METAL
2X SOLDER MASK
OPENING

(1.7)

1 2 3 0.07 MAX
R (0.05) (2.54) ALL AROUND

SOLDER MASK (5.08)

OPENING

LAND PATTERN EXAMPLE

NON-SOLDER MASK DEFINED
SCALE:15X

4222214/B 08/2018

www.ti.com
 MECHANICAL DATA

MPDS094A – APRIL 2001 – REVISED JUNE 2002

DCY (R-PDSO-G4) PLASTIC SMALL-OUTLINE

6,70 (0.264)
6,30 (0.248)
3,10 (0.122)
2,90 (0.114)
4
0,10 (0.004) M

7,30 (0.287) 3,70 (0.146)

6,70 (0.264) 3,30 (0.130)

Gauge Plane
1 2 3
0,25 (0.010)
0,84 (0.033) 0°–10°
2,30 (0.091)
0,66 (0.026)
0,10 (0.004) M
4,60 (0.181) 0,75 (0.030) MIN

1,70 (0.067)
1,80 (0.071) MAX 1,50 (0.059)
0,35 (0.014)
0,23 (0.009)
Seating Plane

0,10 (0.0040) 0,08 (0.003)

0,02 (0.0008)

4202506/B 06/2002

NOTES: A. All linear dimensions are in millimeters (inches).

B. This drawing is subject to change without notice.
C. Body dimensions do not include mold flash or protrusion.
D. Falls within JEDEC TO-261 Variation AA.

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