SLVS044Z September   1997  – April 2025 LM317

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information (Legacy Chip)
    5. 6.5 Thermal Information (New Chip)
    6. 6.6 Electrical Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 NPN Darlington Output Drive
      2. 7.3.2 Overload Block
      3. 7.3.3 Programmable Feedback
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Operation With Low Input Voltage
      3. 7.4.3 Operation at Light Loads
      4. 7.4.4 Operation In Self Protection
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
      1. 8.3.1  0V to 30V Regulator Circuit
      2. 8.3.2  Adjustable Regulator Circuit With Improved Ripple Rejection
      3. 8.3.3  Precision Current-Limiter Circuit
      4. 8.3.4  Tracking Preregulator Circuit
      5. 8.3.5  1.25V to 20V Regulator Circuit With Minimum Program Current
      6. 8.3.6  Battery-Charger Circuit
      7. 8.3.7  50mA, Constant-Current, Battery-Charger Circuit
      8. 8.3.8  Slow Turn-On 15V Regulator Circuit
      9. 8.3.9  AC Voltage-Regulator Circuit
      10. 8.3.10 Current-Limited 6V Charger Circuit
      11. 8.3.11 Adjustable 4A Regulator Circuit
      12. 8.3.12 High-Current Adjustable Regulator Circuit
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Thermal Considerations
          1. 8.5.1.1.1 Heat Sink Requirements
          2. 8.5.1.1.2 Heat Sinking Surface-Mount Packages
            1. 8.5.1.1.2.1 Heatsinking the SOT-223 (DCY) Package
            2. 8.5.1.1.2.2 Heat Sinking the TO-263 (KTT) Package
      2. 8.5.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Device Nomenclature
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.5.1.1.2.2 Heat Sinking the TO-263 (KTT) Package

Figure 8-19 shows the TO-263 measured values of RθJA for different copper area sizes using a typical PCB with 1oz. copper. This figure also shows no solder mask over the copper area used for heat sinking.

As shown in Figure 8-21, increasing the copper area beyond 1 square inch produces very little improvement. The minimum value of RθJA for the TO-263 package mounted to a PCB is 32°C/W.

LM317 RθJA vs Copper (1-oz.) Area for the TO-263 PackageFigure 8-21 RθJA vs Copper (1-oz.) Area for the TO-263 Package

As a design aid, Figure 8-22 shows the maximum allowable power dissipation compared to ambient temperature for the TO-263 device. This figure assumes RθJA is 35°C/W and the maximum junction temperature is 125°C.

LM317 Maximum Power Dissipation vs TAMB for the TO-263 PackageFigure 8-22 Maximum Power Dissipation vs TAMB for the TO-263 Package