SLCS144G July   2004  – August 2026 LM317L

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information (SOIC & SOT-89)
    5. 5.5 Thermal Information (TO-92 & TSSOP)
    6. 5.6 Electrical Characteristics
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 NPN Darlington Output Drive
      2. 6.3.2 Overload Block
      3. 6.3.3 Programmable Feedback
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal operation
      2. 6.4.2 Operation With Low Input Voltage
      3. 6.4.3 Operation at Light Loads
      4. 6.4.4 Operation In Self Protection
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input Capacitor
        2. 7.2.2.2 Output Capacitor
        3. 7.2.2.3 Feedback Resistors
        4. 7.2.2.4 Adjustment Terminal Capacitor
        5. 7.2.2.5 Design Options and Parameters
        6. 7.2.2.6 Output Voltage
        7. 7.2.2.7 Input Short Protection
        8. 7.2.2.8 Ripple Rejection
      3. 7.2.3 Application Curve
    3. 7.3 System Examples
      1. 7.3.1 Regulator Circuit With Improved Ripple Rejection
      2. 7.3.2 0V to 30V Regulator Circuit
      3. 7.3.3 Precision Current-Limiter Circuit
      4. 7.3.4 Tracking Preregulator Circuit
      5. 7.3.5 Slow-Turn On 15V Regulator Circuit
      6. 7.3.6 50mA Constant-Current, Battery-Charger Circuit
      7. 7.3.7 Current-Limited 6V Charger
      8. 7.3.8 High-Current Adjustable Regulator
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
    6. 7.6 Estimating Junction Temperature
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Device Nomenclature
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.3.5 Slow-Turn On 15V Regulator Circuit

The capacitor C1, in combination with the PNP transistor, helps the circuit to slowly start supplying voltage. In the beginning, the capacitor is not charged. Therefore, output voltage starts at 1.9V, as determined by Equation 5. As the capacitor voltage rises, VOUT rises at the same rate. When the output voltage reaches the value determined by R1 and R2, the PNP is turned off.

Equation 5. VC1 + VBE + 1.25V = 0V + 0.65V + 1.25V = 1.9V
LM317L Slow-Turn On of the 15V Regulator CircuitFigure 7-7 Slow-Turn On of the 15V Regulator Circuit
Note: This application circuit tested with legacy chips only (CSO: SHE & CSO: TID); TI's customers are responsible for validating and testing their design implementation to confirm system functionality.