Datasheet LM317 (Texas Instruments) - 2

LM317
SLVS044Z – SEPTEMBER 1997 – REVISED APRIL 2025
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The regulator is floating and detects only the input-to-output differential voltage. Thus, supplies of several hundred volts are regulated as long as the maximum input-to-output differential is not exceeded. That is, avoid short-circuiting the output. By connecting a fixed resistor between the adjustment pin and output, the LM317 is also able to be used as a precision current regulator. Supplies with electronic shutdown are achieved by clamping the adjustment terminal to ground, which programs the output to 1.25V where most loads draw little current. 2 Submit Document Feedback Copyright © 2025 Texas Instruments Incorporated Product Folder Links: LM317 Document Outline 1 Features 2 Applications 3 Description Table of Contents 4 Device Comparison Table 5 Pin Configuration and Functions 6 Specifications 6.1 Absolute Maximum Ratings 6.2 ESD Ratings 6.3 Recommended Operating Conditions 6.4 Thermal Information (Legacy Chip) 6.5 Thermal Information (New Chip) 6.6 Electrical Characteristics 6.7 Typical Characteristics 7 Detailed Description 7.1 Overview 7.2 Functional Block Diagram 7.3 Feature Description 7.3.1 NPN Darlington Output Drive 7.3.2 Overload Block 7.3.3 Programmable Feedback 7.4 Device Functional Modes 7.4.1 Normal Operation 7.4.2 Operation With Low Input Voltage 7.4.3 Operation at Light Loads 7.4.4 Operation In Self Protection 8 Application and Implementation 8.1 Application Information 8.2 Typical Application 8.2.1 Design Requirements 8.2.2 Detailed Design Procedure 8.2.3 Application Curves 8.3 System Examples 8.3.1 0V to 30V Regulator Circuit 8.3.2 Adjustable Regulator Circuit With Improved Ripple Rejection 8.3.3 Precision Current-Limiter Circuit 8.3.4 Tracking Preregulator Circuit 8.3.5 1.25V to 20V Regulator Circuit With Minimum Program Current 8.3.6 Battery-Charger Circuit 8.3.7 50mA, Constant-Current, Battery-Charger Circuit 8.3.8 Slow Turn-On 15V Regulator Circuit 8.3.9 AC Voltage-Regulator Circuit 8.3.10 Current-Limited 6V Charger Circuit 8.3.11 Adjustable 4A Regulator Circuit 8.3.12 High-Current Adjustable Regulator Circuit 8.4 Power Supply Recommendations 8.5 Layout 8.5.1 Layout Guidelines 8.5.1.1 Thermal Considerations 8.5.1.1.1 Heat Sink Requirements 8.5.1.1.2 Heat Sinking Surface-Mount Packages 8.5.1.1.2.1 Heatsinking the SOT-223 (DCY) Package 8.5.1.1.2.2 Heat Sinking the TO-263 (KTT) Package 8.5.2 Layout Examples 9 Device and Documentation Support 9.1 Device Support 9.1.1 Device Nomenclature 9.2 Receiving Notification of Documentation Updates 9.3 Support Resources 9.4 Trademarks 9.5 Electrostatic Discharge Caution 9.6 Glossary 10 Revision History 11 Mechanical, Packaging, and Orderable Information