PCB Board Layout Is Critical When The Power Supply And MCU Live On The Same Board

Focus:

In many simple industrial and consumer products there is printed circuit board (PCB) that contains both a microcontroller (MCU) and a simple off-line power supply. When there is a failure in EMC testing, the customer’s first reaction is often to blame the power supply. But very likely, it is a poor PCB layout that caused the data lines to radiate. After reviewing some of the basic requirements of PCB design, this article goes step-by-step through the details of layout of a PCB for an MCU. Scans of radiated EMI for the example MCU application demonstrate how the errors in pc board layout led to compliance failures. The article also discusses what to do when there is no ground plane; some power-supply related layout problems and how to address them with resistors and decoupling capacitors; and the need to consider manufacturing requirements early in pc board design process.

What you’ll learn:

• How to prevent and solve EMI problems in microcontroller applications with power supplies on board
• How to lay out a PCB with MCU and power supply on board to achieve low EMI

View the Source

Author & Publication:

Kevin Parmenter, Chair, and James Spangler, Co-chair, PSMA Safety and Compliance Committee , How2Power Today, Feb 16 2018

This article summary appears
in the HOW2POWER Design Guide.

The Design Guide offers
organized access to
hundreds of articles
on dozens of power conversion
and power management topics.

The Design Guide search results
include exclusive summaries
and accurate "how to" analysis
to help you make faster,
more informed decisions.

Search
for more articles