SLUSG22 October   2025 UCC35131-Q1

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  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 Insulation Specifications
    6. 6.6 Electrical Characteristics
    7. 6.7 Safety-Related Certifications
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Pre-Production Samples Operating Limits
    3. 7.3 Functional Block Diagram
    4. 7.4 Feature Description
      1. 7.4.1 Power Stage Operation
        1. 7.4.1.1 VDD-COM Voltage Regulation
        2. 7.4.1.2 COM-VEE Voltage Regulation
      2. 7.4.2 Output Voltage Soft Start
      3. 7.4.3 ENA and Power-Good
      4. 7.4.4 Protection Functions
        1. 7.4.4.1 Input Undervoltage Lockout
        2. 7.4.4.2 Input Overvoltage Lockout
        3. 7.4.4.3 Output Undervoltage Protection
        4. 7.4.4.4 Output Overvoltage Protection
        5. 7.4.4.5 Over-Temperature Protection
        6. 7.4.4.6 BSW Pin Faults Protection
    5. 7.5 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 VDD-COM Voltage Regulation
        2. 8.2.2.2 COM-VEE Voltage Regulation and Single Output Configuration
    3. 8.3 System Examples
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    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
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.4.4.1 Input Undervoltage Lockout

The UCC35131-Q1 enters input undervoltage lockout when VVIN voltage becomes lower than the UVLO threshold VVIN_UVLO_F. In UVLO mode, the converter stops switching. After VIN pin voltage falls lower than the VVIN_UVLO_F, UCC35131-Q1 resets all the protections. And then, after the VVIN voltage rises above the UVLO threshold VVIN_UVLO_R, the converter is enabled. Depending on the ENA pin voltage, the converter can start switching, go through the soft-start process, or in the disable mode, waiting for ENA pin voltage becomes high.