SNVS774P May 2004  – October 2015 LM117 , LM317-N


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1Absolute Maximum Ratings
    2. 7.2ESD Ratings
    3. 7.3Recommended Operating Conditions
    4. 7.4Thermal Information, LM117
    5. 7.5Thermal Information, LM317-N
    6. 7.6LM117 Electrical Characteristics
    7. 7.7LM317-N Electrical Characteristics
    8. 7.8Typical Characteristics
  8. Detailed Description
    1. 8.1Overview
    2. 8.2Functional Block Diagram
    3. 8.3Feature Description
      1. 8.3.1Load Regulation
    4. 8.4Device Functional Modes
      1. 8.4.1External Capacitors
      2. 8.4.2Protection Diodes
  9. Application and Implementation
    1. 9.1Application Information
    2. 9.2Typical Applications
      1. 9.2.1 1.25-V to 25-V Adjustable Regulator
        1. Requirements
        2. Design Procedure
        3. 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. 9.2.10Low-Cost 3-A Switching Regulator
      11. 9.2.11Current-Limited Voltage Regulator
      12. 9.2.12Adjusting Multiple On-Card Regulators With Single Control
      13. 9.2.13AC Voltage Regulator
      14. 9.2.1412-V Battery Charger
      15. 9.2.15Adjustable 4-A Regulator
      16. 9.2.16Current-Limited 6-V Charger
      17. 9.2.17Digitally Selected Outputs
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1Layout Guidelines
    2. 11.2Layout Example
    3. 11.3Thermal Considerations
      1. 11.3.1Heatsink Requirements
      2. 11.3.2Heatsinking Surface Mount Packages
        1. the SOT-223 (DCY) Package
        2. the TO-263 (KTT) Package
        3. the TO-252 (NDP) Package
  12. 12Device and Documentation Support
    1. 12.1Documentation Support
      1. 12.1.1Related Documentation
    2. 12.2Related Links
    3. 12.3Community Resources
    4. 12.4Trademarks
    5. 12.5Electrostatic Discharge Caution
    6. 12.6Glossary
  13. 13Mechanical, Packaging, and Orderable Information

1 Features

  • Typ. 0.1% Load Regulation
  • Typ. 0.01%/V Line Regulation
  • 1.5-A Output Current
  • Adjustable Output Down to 1.25 V
  • Current Limit Constant With Temperature
  • 80-dB Ripple Rejection
  • Short-Circuit Protected Output
  • −55°C to 150°C Operating Temperature Range (LM117)

2 Applications

  • Automotive LED Lighting
  • Battery Chargers
  • Post Regulation for Switching Supplies
  • Constant Current Regulators
  • Microprocessor Supplies

Typical Application

LM117 LM317-N 906301.gif
*Needed if device is more than 6 inches from filter capacitors.
†Optional—improves transient response
†† LM117 LM317-N eq1_VOUT_SNVS773.gif

3 Description

The LM117 and LM317-N series of adjustable 3-pin positive voltage regulators are capable of supplying in excess of 1.5 A over a 1.25-V to 37-V output range and a wide temperature range. They are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators.

The LM117 and LM317-N offer full overload protection such as current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is disconnected.

Typically, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors, in which case an input bypass is needed. An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios that are difficult to achieve with standard 3-terminal regulators.

Because the regulator is floating and detects only the input-to-output differential voltage, supplies of several hundred volts can be 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 LM117 and LM317-N can be also used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground, which programs the output to 1.25 V where most loads draw little current.

For applications requiring greater output current, see data sheets for LM150 series (3 A), SNVS772, and LM138 series (5 A), SNVS771. For the negative complement, see LM137 (SNVS778) series data sheet.

Device Information(1)

LM117TO-3 (2)38.94 mm x 25.40 mm
TO (3)8.255 mm × 8.255 mm
LM317-NTO-3 (2)38.94 mm x 25.40 mm
TO-220 (3) 14.986 mm × 10.16 mm
TO-263 (3)10.18 mm × 8.41 mm
SOT-223 (4)6.50 mm × 3.50 mm
TO (3)8.255 mm × 8.255 mm
TO-252 (3)6.58 mm × 6.10 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

4 Revision History

Changes from O Revision (January 2014) to P Revision

  • Added, updated, or renamed the following sections: Description; Pin Configuration and Functions; Specifications; ESD Ratings table; Application and Implementation; Power Supply Recommendations; Layout; Mechanical, Packaging, and Ordering Information Go
  • Removed information regarding LM317A, formerly part of this data sheet. LM317A can now be found in the TI catalog under literature number SNVSAC2 Go

Changes from N Revision (August 2013) to O Revision

  • Deleted MDT Package (over Full Operating Temperature Range) Go
  • Changed Current Limit MIN from 0.112 to 0.15 and TYP from 0.3 to 0.4 for (VIN – VOUT) = 40 V in the LM317A and LM317-N Electrical Characteristics SectionGo
  • Deleted MDT PackageGo