In this episode of Atmel Edge, Analog Aficionado Paul Rako discussed three clever tricks to keep your high-speed circuit boards from radiating energy and failing CE or FCC testing.
Flip your planes, stitch around the edges, or bring the power and ground planes really close together to keep them from oscillating and pumping RF out the edges. These three quick PCB layout tricks will help you pass FCC emissions in no time!
More specifically, says Rako, you take inner plane layers on a four-layer board (or more), bringing them to the outside, effectively creating a containment vessel that prevents radiation from escaping.
“Istvan Novak works at [Oracle] Sun Microsystems,” Rako explains. “He says there is prior art; he didn’t invent it, but he figured out you could stitch RCs all around the edge, and that would keep the radiation from not only leaking out, but from bouncing back in.”
As for the third trick, if you go cut up power planes, you can ultimately bring them very close together.
“You can bring them close together and use other planes to contain the RF – distributing your power and ground with intimate one-mil spacing between the planes. That brings the same kind of damping in as the other trick with putting RCs around the edge,” he adds. “So those three tricks are ways to get you through FCC and CE immunity testing.”
Interested in learning more? You can watch the full video here.