SNVSCR4B July   2024  – November 2025 TLA431 , TLA432

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Parameter Measurement Information
    1. 7.1 Temperature Coefficient
    2. 7.2 Dynamic Impedance
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
      1. 8.4.1 Closed Loop
        1. 8.4.1.1 Stability (Closed Loop)
      2. 8.4.2 Open Loop (Comparator)
  10. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Shunt Regulator/Reference
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Programming Output/Cathode Voltage
          2. 9.2.1.2.2 Total Accuracy
          3. 9.2.1.2.3 Start-Up Time
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Comparator With Integrated Reference
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Basic Operation
            1. 9.2.2.2.1.1 Overdrive
          2. 9.2.2.2.2 Output Voltage and Logic Input Level
            1. 9.2.2.2.2.1 Input Resistance
        3. 9.2.2.3 Application Curve
    3. 9.3 System Examples
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Nomenclature
    2. 10.2 Related Links
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
9.2.2.2.2.1 Input Resistance

TLA431 requires an input resistance in this application to source the reference current (IREF) needed from this device to be in the proper operating regions while turning on. The actual voltage seen at the ref pin is

Equation 6. VREF=VIN-IREF×RIN

Since IREF can be as high as 4µA, the recommendation is to use a resistance small enough that mitigate the error that IREF creates from VIN.