SLUSCV2A June   2017  – April 2021 TPS54308

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Fixed-Frequency PWM Control
      2. 7.3.2  Force Continuous Conduction Mode (FCCM)
      3. 7.3.3  Error Amplifier
      4. 7.3.4  Slope Compensation and Output Current
      5. 7.3.5  Enable and Adjusting Undervoltage Lockout
      6. 7.3.6  Safe Start-Up into Pre-Biased Outputs
      7. 7.3.7  Voltage Reference
      8. 7.3.8  Adjusting Output Voltage
      9. 7.3.9  Internal Soft Start
      10. 7.3.10 Bootstrap Voltage (BOOT)
      11. 7.3.11 Overcurrent Protection
        1. 7.3.11.1 High-Side MOSFET Overcurrent Protection
        2. 7.3.11.2 Low-Side MOSFET Overcurrent Protection
      12. 7.3.12 Output Overvoltage Protection (OVP)
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 TPS54308 8-V to 28-V Input, 5-V Output Converter
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Custom Design With WEBENCH® Tools
        2. 8.2.3.2 Input Capacitor Selection
        3. 8.2.3.3 Bootstrap Capacitor Selection
        4. 8.2.3.4 Output Voltage Set Point
        5. 8.2.3.5 Undervoltage Lockout Set Point
        6. 8.2.3.6 Output Filter Components
          1. 8.2.3.6.1 Inductor Selection
          2. 8.2.3.6.2 Output Capacitor Selection
          3. 8.2.3.6.3 Feedforward Capacitor
      4. 8.2.4 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1 Fixed-Frequency PWM Control

The device uses a fixed-frequency, peak current-mode control. The output voltage is compared through external resistors on the FB pin to an internal voltage reference by an error amplifier. An internal oscillator initiates the turn-on of the high-side power switch. The error amplifier output is compared to the current of the high-side power switch. When the power-switch current reaches the error amplifier output voltage level, the high-side power switch is turned off and the low-side power switch is turned on. The error amplifier output voltage increases and decreases as the output current increases and decreases. The device implements a current limit by clamping the error amplifier voltage to a maximum level. The device also implements a minimum clamp for improved transient-response performance.