EMI Bites: Avoiding Common EMI Pitfalls in PCB Design
When designing PCBs, small layout decisions can lead to significant electromagnetic interference (EMI) issues.
Unusual copper pour structures are a perfect example of subtle design choices that can cause major headaches during certification.
Why are antenna-like copper pours problematic?
- Inconsistent impedance across different sections creates voltage drops.
- Signal coupling to these structures can generate unwanted emissions.
- Connection to the "ground" plane links these emissions to external cables.
- External cables then act as antennas, radiating interference further.
Remember: Even "ground"-connected copper pours need careful consideration!
Signals don’t care about the name you give a net; they only care about impedance.
Copper pours can be perfect pathways for EMI to propagate throughout your system.
For EMI-free designs, I avoid creating antenna-like structures and carefully engineer all "ground" connections.
—Dario
P.S. Want more EMI control strategies to pass EMC?