LM317 - 3-Terminal Adjustable Regulator

Nov 2, 2026

LM317 is a three-terminal adjustable positive-voltage regulator delivering more than 1.5 A across an output-voltage range of 1.25 V to 37 V. The output voltage is set with two external resistors, while typical line regulation is 0.01% and typical load regulation is 0.1%. The device provides current limiting, thermal overload protection, and safe operating-area protection, with overload protection remaining active even if the ADJUST terminal is disconnected.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages26

Reading Time1 h 6 min

AccessFree to download

Features

Applications

Description

Revision History

Pin Configuration and Functions

Specifications

Absolute Maximum Ratings

ESD Ratings

Recommended Operating Conditions

Thermal Information

Electrical Characteristics

Typical Characteristics

Detailed Description

Overview

Functional Block Diagram

Feature Description

Device Functional Modes

Application and Implementation

Application Information

Typical Application

System Examples

Power Supply Recommendations

Layout

Layout Guidelines

Layout Example

Device and Documentation Support

Receiving Notification of Documentation Updates

Community Resources

Trademarks

Electrostatic Discharge Caution

Glossary

Mechanical, Packaging, and Orderable Information

LM317 3-Terminal Adjustable Regulator 1 Features • Output Voltage Range Adjustable From 1.25 V to 37 V • Output Current Greater Than 1.5 A • Internal Short-Circuit Current Limiting • Thermal Overload Protection • Output Safe-Area Compensation 2 Applications • ATCA Solutions • DLP: 3D Biometrics, Hyperspectral Imaging, Optical Networking, and Spectroscopy • DVR and DVS • Desktop PC • Digital Signage and Still Camera • ECG Electrocardiogram • EV HEV Charger: Level 1, 2, and 3 • Electronic Shelf Label • Energy Harvesting • Ethernet Switch • Femto Base Station • Fingerprint and Iris Biometrics • HVAC: Heating, Ventilating, and Air Conditioning • High-Speed Data Acquisition and Generation • Hydraulic Valve • IP Phone: Wired and Wireless • Intelligent Occupancy Sensing • Motor Control: Brushed DC, Brushless DC, LowVoltage, Permanent Magnet, and Stepper Motor • Point-to-Point Microwave Backhaul • Power Bank Solutions • Power Line Communication Modem • Power Over Ethernet (PoE) • Power Quality Meter • Power Substation Control • Private Branch Exchange (PBX) • Programmable Logic Controller • RFID Reader • Refrigerator • Signal or Waveform Generator • Software Defined Radio (SDR) • Washing Machine: High-End and Low-End • X-ray: Baggage Scanner, Medical, and Dental 3 Description The LM317 device is an adjustable three-terminal positive-voltage regulator capable of supplying more than 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. Device Information(1) | PART NUMBER | PACKAGE | BODY SIZE (NOM) | | --- | --- | --- | | LM317DCY | SOT-223 (4) | 6.50 mm × 3.50 mm | | LM317KCS | TO-220 (3) | 10.16 mm × 9.15 mm | | LM317KCT | TO-220 (3) | 10.16 mm × 8.59 mm | | LM317KTT | TO-263 (3) | 10.16 mm × 9.01 mm | (1) For all available packages, see the orderable addendum atthe end of the data sheet. Battery-Charger Circuit VI Copyright © 2016, Texas Instruments Incorporated 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. LM317 SLVS044X –SEPTEMBER 1997–REVISED SEPTEMBER 2016 [www.ti.com](www.ti.com) | Table of Contents | | | | --- | --- | --- | | 1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Pin Configuration and Functions ......................... 3
6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions ....................... 4
6.4 Thermal Information .................................................. 4
6.5 Electrical Characteristics ........................................... 5
6.6 Typical Characteristics .............................................. 6
7 Detailed Description .............................................. 8
7.1 Overview ................................................................... 8
7.2 Functional Block Diagram ......................................... 8
7.3 Feature Description ................................................... 8 | 7.4 Device Functional Modes.......................................... 9
8 Applica

FAQs

What output voltage range does the LM317 support?

The LM317 supports an adjustable output-voltage range of 1.25 V to 37 V.

How many external resistors are required to set the LM317 output voltage?

It requires only two external resistors to set the output voltage.

What protection features are built into the LM317?

The LM317 includes internal current limiting, thermal overload protection, and output safe-area compensation. Overload protection remains functional even if the ADJUST terminal is disconnected.

Nov 2, 2026

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