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Placing power planes next to each other. Will that create EMI problems?

Tom Yunghans , 03-15-2021, 09:35 PM
Hi Robert,

Just watched your video chat with Rick Hartley (a couple of times). Really good insight in that. Thank you.

Rick made a lot of negative comments about placing different power planes next to each other in your stackup. In your IMX6 Rex design that you used in your Advanced PCB Design course, you placed four power planes right in the middle of that stackup (layers 5,6,7 and 8). They have very minimal distance between them (4-5 mils). You do have solid ground layers on layers 4 and 9 so the fields between these layers will not intermix with the signal layers, but I believe Rick is saying that the interaction between the power fields on those power layers might result in high frequency noise on the power layers and will likely cause your design to emit unacceptable EMI radiation levels.. He never did mention the EMI levels he was referring to. For example, the difference between FCC EMI (used on home appliances) and DO-160 EMI levels (used in aircraft) can be quite dramatic.

Was the iMX6 Rex design subjected to any EMI testing? What other approaches might you consider for that board after this discussion with Rick?

Thank you!
robertferanec , 03-20-2021, 03:55 AM
Yes, we tested all our iMX6 Rex boards - no problems:

- https://www.imx6rex.com/2014/04/imx6...-testing-pass/
- https://www.imx6rex.com/?s=emc&submit=Search

PS: All discussions I have are very specific to experience of people. In the videos I try to point out topics what we need to be aware of or we need to be careful about, but ... it doesn't mean that other things will not work.
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