SLVS757E March   2007  – July 2022 TPS5450

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  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  Oscillator Frequency
      2. 7.3.2  Voltage Reference
      3. 7.3.3  Enable (ENA) and Internal Slow-Start
      4. 7.3.4  Undervoltage Lockout (UVLO)
      5. 7.3.5  Boost Capacitor (BOOT)
      6. 7.3.6  Output Feedback (VSENSE) and Internal Compensation
      7. 7.3.7  Voltage Feed-Forward
      8. 7.3.8  Pulse-Width-Modulation (PWM) Control
      9. 7.3.9  Overcurrent Limiting
      10. 7.3.10 Overvoltage Protection
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation near Minimum Input Voltage
      2. 7.4.2 Operation With ENA Control
  8. 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 Switching Frequency
        2. 8.2.2.2 Output Voltage Setpoint
        3. 8.2.2.3 Input Capacitors
        4. 8.2.2.4 Output Filter Components
        5. 8.2.2.5 Inductor Selection
        6. 8.2.2.6 Capacitor Selection
        7.       43
        8. 8.2.2.7 Boot Capacitor
        9. 8.2.2.8 Catch Diode
        10. 8.2.2.9 Advanced Information
          1. 8.2.2.9.1 Output Voltage Limitations
          2. 8.2.2.9.2 Internal Compensation Network
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Calculations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.4 Undervoltage Lockout (UVLO)

The TPS5450 incorporates an UVLO circuit to keep the device disabled when VIN (the input voltage) is below the UVLO start voltage threshold. During power-up, internal circuits are held inactive and the internal slow-start is grounded until VIN exceeds the UVLO start threshold voltage. Once the UVLO start threshold voltage is reached, the internal slow-start is released and device start-up begins. The device operates until VIN falls below the UVLO stop threshold voltage. The typical hysteresis in the UVLO comparator is 330  mV.