36V-3A Adjustable Efficient DC to DC Step-Down (Buck) Converter

A DC-to-DC converter is one of the most commonly used circuit topologies in electronics, especially in power supply applications. There are three major types of DC-to-DC converters (non-isolated): Buck, Boost, and Buck-Boost. Sometimes a buck converter is also called a step-down converter and a boost converter is also called a step-up converter.

In this article/video, I introduce an adjustable buck converter circuit that uses an advanced converter chip, made by Texas Instruments, which is TPS5430. It’s a high-frequency and 95% efficient chip. In the PCB layout design of such converters, several PCB design rules should be followed, otherwise, the circuit might generate a significant amount of radiated emission and suffer output instability.

To design the schematic and PCB, I used Altium Designer 22 and used the manufacturer part search feature to directly import the components into the PCB project. Then, generated the BOM list using the free OctoPart services. To get high-quality fabricated boards, I sent the Gerbers to PCBWay and tested the circuit for output stability and noise, using a DC load, A multimeter, and an oscilloscope. Soon later, I will also perform the step-response test and demonstrate the results. Stay connected!


Input Voltage: 5.5V to 36V

Output Voltage: 1.22Vmin (variable)

Output Current (continuous): 3A

Output Current (peak): 4A

Maximum output voltage drop: 10mV (3A load)

Output Noise: 12mVp-p (no load), 43mVp-p (3A load), 20MHz-BW

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