SNVS774Q May   2004  – June 2020 LM117 , LM317-N

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Typical Application
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions, Metal Can Packages
    2.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information, LM117
    5. 7.5 Thermal Information, LM317-N
    6. 7.6 LM117 Electrical Characteristics
    7. 7.7 LM317-N Electrical Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Load Regulation
    4. 8.4 Device Functional Modes
      1. 8.4.1 External Capacitors
      2. 8.4.2 Protection Diodes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1  1.25-V to 25-V Adjustable Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2  5-V Logic Regulator With Electronic Shutdown
      3. 9.2.3  Slow Turnon 15-V Regulator
      4. 9.2.4  Adjustable Regulator With Improved Ripple Rejection
      5. 9.2.5  High Stability 10-V Regulator
      6. 9.2.6  High-Current Adjustable Regulator
      7. 9.2.7  Emitter-Follower Current Amplifier
      8. 9.2.8  1-A Current Regulator
      9. 9.2.9  Common-Emitter Amplifier
      10. 9.2.10 Low-Cost 3-A Switching Regulator
      11. 9.2.11 Current-Limited Voltage Regulator
      12. 9.2.12 Adjusting Multiple On-Card Regulators With Single Control
      13. 9.2.13 AC Voltage Regulator
      14. 9.2.14 12-V Battery Charger
      15. 9.2.15 Adjustable 4-A Regulator
      16. 9.2.16 Current-Limited 6-V Charger
      17. 9.2.17 Digitally Selected Outputs
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Thermal Considerations
        1. 11.1.1.1 Heatsink Requirements
        2. 11.1.1.2 Heatsinking Surface Mount Packages
          1. 11.1.1.2.1 Heatsinking the SOT-223 (DCY) Package
          2. 11.1.1.2.2 Heatsinking the TO-263 (KTT) Package
          3. 11.1.1.2.3 Heatsinking the TO-252 (NDP) Package
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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11.1.1.2.2 Heatsinking the TO-263 (KTT) Package

Figure 39 shows for the TO-263 the measured values of RθJA for different copper area sizes using a typical PCB with 1-oz. copper and no solder mask over the copper area used for heatsinking.

As shown in Figure 39, increasing the copper area beyond 1 square inch produces very little improvement. It must also be observed that the minimum value of RθJA for the TO-263 package mounted to a PCB is 32°C/W.

LM117 LM317-N 906355.pngFigure 39. RθJA vs Copper (1-oz.) Area for the TO-263 Package

As a design aid, Figure 40 shows the maximum allowable power dissipation compared to ambient temperature for the TO-263 device (assuming RθJA is 35°C/W and the maximum junction temperature is 125°C).

LM117 LM317-N 906356.pngFigure 40. Maximum Power Dissipation vs TAMB for the TO-263 Package