📌 Project Overview
This project is a PCB design and power electronics practice project for a wide-input DC-DC Buck Converter based on the Texas Instruments LMR38020.
The converter is designed to step down a 14V–48V input supply to a regulated 12V output at 1A, operating at 400kHz switching frequency.
This project focuses on professional schematic capture, component selection, switching regulator calculations, and PCB layout best practices using Altium Designer 25.2.1. It emphasizes correct power loop routing, thermal considerations, and EMI-aware layout techniques.
Fabrication and hardware validation are not included in this version. The objective is to strengthen practical knowledge in industrial-grade power supply PCB design.
- Wide input voltage range (14V – 48V)
- Regulated 12V output @ 1A
- 400kHz switching frequency configuration
- Synchronous buck topology
- Adjustable output via feedback network
- Properly designed power loop layout
- Thermal pad grounding with via stitching
- Industrial-style PCB layout discipline
- Understanding synchronous buck converter operation
- Calculating switching frequency (RT resistor selection)
- Inductor and capacitor selection based on ripple requirements
- Designing feedback divider network
- Power loop minimization in PCB layout
- SW node copper control for EMI reduction
- Thermal pad design and heat dissipation strategy
- Practical application of datasheet-driven design
| File | Description |
|---|---|
lmr38020_schematic.pdf |
Complete schematic diagram |
pcb_layout.png |
2D PCB layout image |
pcb_3d_view.png |
3D PCB visualization |
design_calculations.md |
Design equations and component selection details |
bom.xlsx |
Bill of Materials |
- LMR38020SDDAR (HSOIC-8 with PowerPAD)
- Shielded Power Inductor (~68µH)
- X7R Ceramic Input and Output Capacitors
- Bootstrap Capacitor (100nF)
- RT Resistor (~66kΩ for 400kHz)
- Feedback Resistors for 12V Output
- Altium Designer 25.2.1
- The LMR38020 operates as a synchronous step-down (buck) converter.
- The high-side MOSFET switches at 400kHz.
- Energy is transferred through the inductor to the output capacitor.
- The feedback network regulates the output voltage to 12V.
- The RT resistor sets the switching frequency.
- Proper PCB layout minimizes switching noise and improves thermal performance.
- High-current switching loop kept minimal
- Dedicated ground strategy
- Exposed PowerPAD connected to ground with thermal vias
- Controlled SW node copper area to reduce EMI
- Wide traces used for VIN, SW, VOUT, and PGND
- Feedback trace routed away from switching node
Mohit Jagtap
Electronics & Telecommunication Engineering
Dr. D. Y. Patil Institute of Engineering Management and Research
Akurdi, Pune