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

8.2.12 Adjusting Multiple On-Card Regulators With Single Control

Figure 30 shows how multiple LM317A regulators can be controlled by setting one resistor. Because each device maintains the reference voltage of about 1.25 V between its VOUT and ADJ pins, we can connect each ADJ rail to a single resistor, setting the same output voltage across all devices. This allows for independent outputs, each responding to its corresponding input only. Designers must also consider that by the nature of the circuit, changes to R1 and R2 will affect all regulators.

LM317A 906324-3.gif

NOTE:

*All outputs within ±100 mV
†Minimum load—10 mA
Figure 30. Adjusting Multiple On-Card Regulators With Single Control