Low EMI Layer stackup tips - Picture this first!

If current always flows in loops, how can we visualize the current loop during signal propagations in a PCB?

A lot can be said in one picture.

This picture should help you see the importance of the return reference plane.

The current loop is formed not only by the signal (forward) current but is completed by the displacement current following the signal front wave, and the return current.

I still see (too) many PCB designs with two layers and both dedicated for digital signals.

No Bueno!

This is one of the most sure and reliable ways to FAIL EMC tests on the first pass.

A question I ask myself during the layout design:

Are you engineering the current path properly?

I hope this helps you.

Dario

fresuelectronics.com

---

Action list:

1. Get the New EMI Quick Fixes Guide - 2025

EMI Quick Fixes Guide

Buy Now

---