SLVUDZ7 September   2026

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
      1. 1.3.1 Application Circuit Diagram
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Test Setup and Procedure
      1. 2.1.1 EVM Connections
      2. 2.1.2 Test Equipment
  9. 3Implementation Results
    1. 3.1 Test Data and Performance Curves
      1. 3.1.1 Conversion Efficiency
      2. 3.1.2 Operating Waveforms
        1. 3.1.2.1 Load Transient Response
  10. 4Hardware Design Files
    1. 4.1 Schematic
    2. 4.2 PCB Layout
    3. 4.3 Bill of Materials
  11. 5Device and Documentation Support
    1. 5.1 Device Support
      1. 5.1.1 Development Support
    2. 5.2 Documentation Support
      1. 5.2.1 Related Documentation
        1. 5.2.1.1 PCB Layout Resources
        2. 5.2.1.2 Thermal Design Resources
  12. 6Additional Information
    1. 6.1 Trademarks

1.1 Introduction

The LM25139-Q1EVM-20A high-density EVM is designed to use a regulated or non-regulated high-voltage input rail ranging from 5.5V to 36V to produce a tightly-regulated output voltage of 5V with load currents up to 20A. This wide VIN range DC/DC design offers outsized voltage rating and operating margin to withstand supply rail voltage transients. The PowerTrain passive components selected for this EVM are available from multiple component vendors.

The default configuration of this EVM has an output voltage of 5V, a switching frequency of 440kHz, and uses a series resistor (RSENSE) to sense the output current. Please see below for modifications that can be made to the EVM for other common configurations:

To configure the EVM for a different output voltage:

  • Replace R4 with a 0Ω resistor for an output voltage of 3.3V.
  • DNP R4 and populate RFBT and RFBB for other output voltages. Refer to the device data sheet to select component values.

To configure the EVM for a different switching frequency:

  • DNP RT1 and populate RT2 for other switching frequencies with DRSS enabled. Refer to the device data sheet to select component values.
  • DNP RT2 and populate RT1 for other switching frequencies with DRSS disabled. Refer to the device data sheet to select component values.
  • Synchronize the FPWM/MODE pin to an external clock ±20% of the RT programmed frequency up to 3.2MHz. Refer to the device data sheet for more details.

To configure the EVM for inductor DCR sensing:

  1. Replace RSENSE with a 0Ω resistor.
  2. DNP R2 and R3.
  3. Populate R1 with a 0Ω resistor.
  4. Populate RDCRS and CDCRS. Refer to the device data sheet to select component values.

The LM25139-Q1 synchronous buck controller used in the EVM has the following features:

  • Wide input voltage (wide VIN) range of 3.5V to 42V
  • Spread spectrum modulation for lower EMI
  • Wide duty cycle range with low tON(min) and tOFF(min)
  • Ultra-low shutdown and no-load standby quiescent currents
  • Peak current-mode control loop architecture with cycle-by-cycle hiccup overcurrent protection
  • Integrated, high-current MOSFET gate drivers
CAUTION:
LM25139-Q1EVM-20A
Hot surface. Contact can cause burns. Do not touch.