SDAA210 November   2025 LM5125-Q1 , LM51251A-Q1 , LM5125A-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Application Implementation
  6. 3Design Considerations
  7. 4Test Results
    1. 4.1 Efficiency Measurements
    2. 4.2 Device Features
      1. 4.2.1 Soft-Start (SS)
      2. 4.2.2 Over-Voltage Protection (OVP)
      3. 4.2.3 Second phase enable (EN2)
      4. 4.2.4 Bypass mode
    3. 4.3 Load Transient
    4. 4.4 Line Transient
    5. 4.5 Temperature Measurements
    6. 4.6 Bode Plot
  8. 5Summary
  9. 6References

Abstract

The LM5125x is a dual-phase synchronous controller that provides a regulated output voltage for lower up to equal input voltages, also supporting VIN to VOUT bypass mode. The LM5125x can support applications like high-end audio power supplies, voltage stabilizer modules and start-stop applications. Dual-phase, asynchronous operation of the device is also possible, which allows for lower BOM cost and complexity at a reasonable decrease in overall converter performance. This application note shows the evaluation of the LM5125x in asynchronous mode and gives design guidelines to help engineers to design properly for practical applications.