SNVSCB1C December   2022  – February 2024 TPSM33615 , TPSM33625

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 System Characteristics
    7. 6.7 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  Input Voltage Range
      2. 7.3.2  Output Voltage Selection
      3. 7.3.3  Input Capacitors
      4. 7.3.4  Output Capacitors
      5. 7.3.5  Enable, Start-Up, and Shutdown
      6. 7.3.6  External CLK SYNC (with MODE/SYNC)
        1. 7.3.6.1 Pulse-Dependent MODE/SYNC Pin Control
      7. 7.3.7  Switching Frequency (RT)
      8. 7.3.8  Power-Good Output Operation
      9. 7.3.9  Internal LDO, VCC and VOUT/FB Input
      10. 7.3.10 Bootstrap Voltage and VBOOT-UVLO (BOOT Terminal)
      11. 7.3.11 Spread Spectrum
      12. 7.3.12 Soft Start and Recovery from Dropout
        1. 7.3.12.1 Recovery from Dropout
      13. 7.3.13 Overcurrent Protection (Hiccup Mode)
      14. 7.3.14 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
        1. 7.4.3.1 CCM Mode
        2. 7.4.3.2 Auto Mode – Light-Load Operation
          1. 7.4.3.2.1 Diode Emulation
          2. 7.4.3.2.2 Frequency Reduction
        3. 7.4.3.3 FPWM Mode – Light-Load Operation
        4. 7.4.3.4 Minimum On-Time (High Input Voltage) Operation
        5. 7.4.3.5 Dropout
  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  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Choosing the Switching Frequency
        3. 8.2.2.3  Setting the Output Voltage
        4. 8.2.2.4  Input Capacitor Selection
        5. 8.2.2.5  Output Capacitor Selection
        6. 8.2.2.6  VCC
        7. 8.2.2.7  CFF Selection
        8. 8.2.2.8  Power Good Signal
        9. 8.2.2.9  Maximum Ambient Temperature
        10. 8.2.2.10 Other Connections
      3. 8.2.3 Application Curves
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Ground and Thermal Considerations
      2. 8.5.2 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 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
      3. 9.1.3 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
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.4.3.3 FPWM Mode – Light-Load Operation

In FPWM mode, frequency is maintained while the output is lightly loaded. To maintain frequency, a limited reverse current is allowed to flow through the inductor. Reverse current is limited by negative current limit circuitry, see Section 6.5 for negative current limit values.

GUID-85462E56-398E-442A-A502-D50EE4551511-low.gif
In FPWM mode, Continuous Conduction (CCM) is possible even if IOUT is less than half of Iripple.
Figure 7-15 FPWM Mode Operation

For all devices, in FPWM mode, frequency reduction is still available if output voltage is high enough to command minimum on time even while lightly loaded, allowing good behavior during faults which involve output being pulled up.