SBVS398A December   2021  – September 2022 TPS7A21

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Smart Enable (EN)
      2. 7.3.2 Low Output Noise
      3. 7.3.3 Active Discharge
      4. 7.3.4 Dropout Voltage
      5. 7.3.5 Foldback Current Limit
      6. 7.3.6 Undervoltage Lockout
      7. 7.3.7 Thermal Overload Protection (TSD)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Functional Mode Comparison
      2. 7.4.2 Normal Operation
      3. 7.4.3 Dropout Operation
      4. 7.4.4 Disabled
  8. Applications and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Recommended Capacitor Types
      2. 8.1.2 Input and Output Capacitor Requirements
      3. 8.1.3 Load Transient Response
      4. 8.1.4 Undervoltage Lockout (UVLO) Operation
      5. 8.1.5 Power Dissipation (PD)
      6. 8.1.6 Estimating Junction Temperature
      7. 8.1.7 Recommended Area For Continuous Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Power Dissipation and Device Operation
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 DSBGA Mounting
        2. 8.4.1.2 DSBGA Light Sensitivity
      2. 8.4.2 Layout Example
  9. Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Device Nomenclature
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  10. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Mechanical Data

Thermal Overload Protection (TSD)

Thermal shutdown disables the output when the junction temperature TJ rises to the shutdown temperature threshold TSD. The thermal shutdown circuit hysteresis requires the temperature to fall to a lower temperature before turning on again. The thermal time constant of the semiconductor die is fairly short; thus, the device may cycle on and off when thermal shutdown is reached until power dissipation is reduced.

Power dissipation during start up can be high from large VIN – VOUT voltage drops across the device or from high inrush currents charging large output capacitors. Under some conditions, the thermal shutdown protection disables the device before start up completes.

For reliable operation, limit the junction temperature to the maximum listed in the Section 6.3 table. Operation above this maximum temperature causes the regulator to exceed operational specifications.

Although the thermal shutdown circuitry is designed to protect against temporary thermal overload conditions, this circuitry is not intended to replace proper thermal design. Continuously running the regulator into thermal shutdown or above the maximum recommended junction temperature reduces long-term reliability.