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Platform forum

Sniper2 , 11-03-2025, 10:04 PM

So i have metal enclosure and metal mounting point and connectors with shield going outside.
I am considering makeing a Chasis_GND guard ring around the board. But then do i also need to do a GND guard ring inside of that? also i will connect both at 1 point only next to the PWR connector i think.
Is this ok ? or do i need to do something more/else?

Robert Feranec , 11-04-2025, 07:59 AM

once i experimented with guard ring - the result was, that the best solution was to connect it directly with multiple 0R to the board GND. Since then I have never used it. But, I guess there are situations when it can be useful. I dont rember what aexactly were the problems, but maybe something with ESD

Sniper2 , 11-04-2025, 02:23 PM

So I should skip chasis ring and do a gnd ring instead?

Sniper2 , 11-04-2025, 02:24 PM

Btw I am noing this to minimise esd and potentially conducted emissions

Sniper2 , 11-04-2025, 02:25 PM

My gnd is galvanic isolated so I am not sure if I should tie it to chassis or not

Sniper2 , 11-04-2025, 02:25 PM

Then again I have usb and ethernet that go through the metallic chasis

QDrives , 11-05-2025, 01:35 AM

The guardring can help with ESD and EMC. For that you would want/need multiple connections to Gnd as your source is not just at that one spot.

Sniper2 , 11-05-2025, 05:17 AM

Ok thx

Sniper2 , 11-09-2025, 09:21 PM

there is a Class D amplifier inside

Sniper2 , 11-09-2025, 09:21 PM

should i be waried?

QDrives , 11-10-2025, 03:21 PM

Not for the class D part, but perhaps the sensitive analog input.

Sniper2 , 11-10-2025, 03:26 PM

Input is i2s

Sniper2 , 11-10-2025, 03:26 PM

Well I am emi fobic

QDrives , 11-10-2025, 07:54 PM

Then I better not tell you that the best capacitors to use would be 0306, 0508 or 0612 (not to mistaken with 0603, 0805 and 1206).
And to lower inductance even more you add multiple in parallel.
'Plane' to 'plane' capacitance may also help. Add some common mode chokes.
Just not to much capacitance as you do not want to go into low frequency, just high enough for ESD and EMI to be 'safe'.

Oops, I just did. 😉

Sniper2 , 11-10-2025, 08:33 PM

THX