Non-Isolated Buck DC-DC Converter

This reference design provides design guide, data and other contents of multiple non-isolated buck DC-DC converter power supplies. Multiple variations of the power supply are optimized for various outputs, loads and board mounting areas.

Simple block diagram of non-isolated buck DC-DC converter.
Simple Block Diagram
Efficiency curves of non-isolated buck DC-DC converter.
Efficiency Curves


Input voltage DC 12 V
Output voltage/current 5V/5A、5V/8A、5V/12A、3.3V/10A、3.3V/13.3A、3.3V/18.2A、1.5V/10A、1.05V/10A
Optimization Each design is optimized for efficiency at 50% load and 100% load and also for small size
Design Variations 24


Photo of non-isolated buck DC-DC converter.
  • Non-Isolated Buck DC-DC Converter with synchronous rectification
  • 8 power supply circuit designs with different output voltage and output power
  • Each power supply circuit design has 3 variations

Reference design files

Design, Document

“Design・Document” contains the documents listed below.


Design, File

“Design・File” contains the contents listed below.

*1:Actual PCB was designed on CR5000BD. The other files were made from CR5000BD file.
*2:The data was generated on CR5000BD.

Toshiba items

Part Number Device Category Portion Usage Description
TPH3R203NL MOSFET High-side 30 V/3.2 mΩ (max) @VGS = 10 V/SOP Advance
TPH4R003NL MOSFET High-side 30 V/4 mΩ (max) @VGS = 10 V/SOP Advance
TPH8R903NL MOSFET High-side/Low-side 30 V/8.9 mΩ (max) @VGS = 10 V/SOP Advance
TPH11003NL MOSFET High-side/Low-side 30 V/11 mΩ (max) @VGS = 10 V/SOP Advance
TPN4R303NL MOSFET High-side 30 V/4.3 mΩ (max) @VGS = 10 V/TSON Advance
TPN8R903NL MOSFET High-side/Low-side 30 V/8.9 mΩ (max) @VGS = 10 V/TSON Advance
TPN11003NL MOSFET High-side 30 V/11 mΩ (max) @VGS = 10 V/TSON Advance
TPHR6503PL1 MOSFET Low-side 30 V/0.65 mΩ (max) @VGS = 10 V/SOP Advance(N)
TPHR9203PL1 MOSFET Low-side 30 V/0.92 mΩ (max) @VGS = 10 V/SOP Advance(N)
TPH2R003PL MOSFET Low-side 30 V/2 mΩ (max) @VGS = 10 V/SOP Advance
TPH2R903PL MOSFET Low-side 30 V/2.9 mΩ (max) @VGS = 10 V/SOP Advance
TPH4R803PL MOSFET Low-side 30 V/4.8 mΩ (max) @VGS = 10 V/SOP Advance
TPN1R603PL MOSFET Low-side 30 V/1.6 mΩ (max) @VGS = 10 V/TSON Advance
TPN2R903PL MOSFET Low-side 30 V/2.9 mΩ (max) @VGS = 10 V/TSON Advance
TPN5R203PL MOSFET Low-side 30 V/5.2 mΩ (max) @VGS = 10 V/TSON Advance

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