SLVSIO8 September   2026 TPS638221

PRODMIX  

  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 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Scheme
        1. 7.3.1.1 Buck Operation
        2. 7.3.1.2 Boost Operation
        3. 7.3.1.3 Buck-Boost Operation
      2. 7.3.2 Operation Mode
        1. 7.3.2.1 PFM Operation
        2. 7.3.2.2 Forced-PWM Operation (FPWM)
        3. 7.3.2.3 Ultra-sonic Mode Operation
      3. 7.3.3 Undervoltage Lockout (UVLO)
      4. 7.3.4 Enable and Soft Start
      5. 7.3.5 Protection Functions
        1. 7.3.5.1 Input Voltage Protection (IVP)
        2. 7.3.5.2 Output Voltage Protection (OVP)
        3. 7.3.5.3 Current Limit Mode and Overcurrent Protection
        4. 7.3.5.4 Output Short Circuit Protection (Hiccup)
        5. 7.3.5.5 Thermal Shutdown
      6. 7.3.6 Power Good
      7. 7.3.7 Load Disconnect
      8. 7.3.8 Output Discharge
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 3.3V Output Power Supply
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Output Capacitor Selection
          3. 8.2.1.2.3 Input Capacitor Selection
          4. 8.2.1.2.4 Setting the Output Voltage
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 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 Export Control Notice
    8. 9.8 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1.     67

7.4 Device Functional Modes

The device has two functional modes: off and on. The device enters the on mode when the voltage on the VIN pin is higher than the UVLO threshold and a high logic level is applied to the EN pin. The device enters the off mode when the voltage on the VIN pin is lower than the UVLO threshold or a low logic level is applied to the EN pin.

TPS638221 Device Functional ModesFigure 7-5 Device Functional Modes