SNVSAC2A March   2015  – June 2020 LM317A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Typical Application
  3. 3 Description
    1.     Revision History
  4. 4 Device Comparison Table
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Load Regulation
    4. 7.4 Device Functional Modes
      1. 7.4.1 External Capacitors
      2. 7.4.2 Protection Diodes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1  1.25-V to 25-V Adjustable Regulator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2  5-V Logic Regulator With Electronic Shutdown
      3. 8.2.3  Slow Turnon 15-V Regulator
      4. 8.2.4  Adjustable Regulator With Improved Ripple Rejection
      5. 8.2.5  High-Stability 10-V Regulator
      6. 8.2.6  High-Current Adjustable Regulator
      7. 8.2.7  Emitter-Follower Current Amplifier
      8. 8.2.8  1-A Current Regulator
      9. 8.2.9  Common-Emitter Amplifier
      10. 8.2.10 Low-Cost 3-A Switching Regulator
      11. 8.2.11 Current-Limited Voltage Regulator
      12. 8.2.12 Adjusting Multiple On-Card Regulators With Single Control
      13. 8.2.13 AC Voltage Regulator
      14. 8.2.14 12-V Battery Charger
      15. 8.2.15 Adjustable 4-A Regulator
      16. 8.2.16 Current-Limited 6-V Charger
      17. 8.2.17 Digitally-Selected Outputs
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Thermal Considerations
        1. 10.1.1.1 Heatsink Requirements
        2. 10.1.1.2 Heatsinking Surface Mount Packages
          1. 10.1.1.2.1 Heatsinking the SOT-223 (DCY) Package
          2. 10.1.1.2.2 Heatsinking the TO-252 (NDP) Package
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10.1.1.2.2 Heatsinking the TO-252 (NDP) Package

If the maximum allowable value for θJA is found to be ≥54°C/W (typical rated value) for the TO-252 package, no heatsink is needed because the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for θJA falls below these limits, a heatsink is required.

As a design aid, Table 1 shows the value of the θJA of NDP the package for different heatsink area. The copper patterns that we used to measure these θJAs are shown in Figure 43. Figure 39 reflects the same test results as what are in Table 1.

Figure 40 shows the maximum allowable power dissipation versus ambient temperature for the TO-252 device. Figure 41 shows the maximum allowable power dissipation versus copper area (in2) for the TO-252 device. See the AN-1028 Maximum Power Enhancement Techniques for Power Packages application note for thermal enhancement techniques to be used with SOT-223 and TO-252 packages.

Table 1. θJA Different Heatsink Area

Layout Copper Area Thermal Resistance
Top Side (in2)(1) Bottom Side (in2) (θJA°C/W) TO-252
1 0.0123 0 103
2 0.066 0 87
3 0.3 0 60
4 0.53 0 54
5 0.76 0 52
6 1 0 47
7 0.066 0.2 84
8 0.066 0.4 70
9 0.066 0.6 63
10 0.066 0.8 57
11 0.066 1 57
12 0.066 0.066 89
13 0.175 0.175 72
14 0.284 0.284 61
15 0.392 0.392 55
16 0.5 0.5 53
(1) Tab of device attached to topside of copper.
LM317A 906361.gifFigure 39. θJA vs 2-oz. Copper Area for TO-252
LM317A 906362.gifFigure 41. Maximum Allowable Power Dissipation vs 2-oz. Copper Area for TO-252
LM317A 906363.gifFigure 40. Maximum Allowable Power Dissipation vs Ambient Temperature for TO-252
LM317A 906364.gifFigure 42. Top View of the Thermal Test Pattern in Actual Scale
LM317A 906365.gifFigure 43. Bottom View of the Thermal Test Pattern in Actual Scale