SLVSDG6C May   2016  – March 2026 TPS54302

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Fixed-Frequency PWM Control
      2. 6.3.2  Pulse Skip Mode
      3. 6.3.3  Error Amplifier
      4. 6.3.4  Slope Compensation and Output Current
      5. 6.3.5  Enable and Adjusting Undervoltage Lockout
      6. 6.3.6  Safe Start-Up into Prebiased Outputs
      7. 6.3.7  Voltage Reference
      8. 6.3.8  Adjusting Output Voltage
      9. 6.3.9  Internal Soft Start
      10. 6.3.10 Bootstrap Voltage (BOOT)
      11. 6.3.11 Overcurrent Protection
        1. 6.3.11.1 High-Side MOSFET Overcurrent Protection
        2. 6.3.11.2 Low-Side MOSFET Overcurrent Protection
      12. 6.3.12 Spread Spectrum
      13. 6.3.13 Output Overvoltage Protection (OVP)
      14. 6.3.14 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Eco-mode Operation
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 TPS54302 8V to 28V Input, 5V Output Converter
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Input Capacitor Selection
        2. 7.2.3.2 Bootstrap Capacitor Selection
        3. 7.2.3.3 Output Voltage Set Point
        4. 7.2.3.4 Undervoltage Lockout Set Point
        5. 7.2.3.5 Output Filter Components
          1. 7.2.3.5.1 Inductor Selection
          2. 7.2.3.5.2 Output Capacitor Selection
          3. 7.2.3.5.3 Feedforward Capacitor
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.1 Overview

The TPS54302 device is a 28V, 3A, synchronous step-down (buck) converter with two integrated n-channel MOSFETs. To improve performance during line and load transients the device implements a constant-frequency, peak current-mode control which reduces output capacitance. The optimized internal compensation network minimizes the external component counts and simplifies the control loop design.

The switching frequency of the device is fixed to 400kHz.

The TPS54302 device starts switching when VIN is 4.5V. The operating current is 45μA (typical) when not switching and under no load. When the device is disabled, the supply current is 2µA (typical).

The integrated 85mΩ high-side MOSFET and 40mΩ low-side MOSFET allow for high-efficiency power-supply designs with continuous output currents up to 3A.

The TPS54302 device reduces the external component count by integrating the boot recharge diode. The bias voltage for the integrated high-side MOSFET is supplied by an external capacitor on the BOOT to PH pins. The boot capacitor voltage is monitored by an UVLO circuit and turns off the high-side MOSFET when the voltage falls below a preset threshold of 2.1V (typical).

The device minimizes excessive output overvoltage transients by taking advantage of the overvoltage comparator. When the regulated output voltage is greater than 108% of the nominal voltage, the overvoltage comparator is activated, and the high-side MOSFET is turned off and masked from turning on until the output voltage is lower than 104%.

The TPS54302 device has internal 5ms soft-start time to minimize inrush currents.