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AmedeoDS , 07-14-2025, 07:28 AM

Hi everyone,

I’m having an issue in Altium Designer with a via that’s supposed to connect to an internal power plane. Here are the details:

There is a via on the Bottom layer that ties to the 5 V power pin of a PSoC5 microcontroller.

This via should make direct contact with the internal 5 V plane.

However, nearby there are other vias that do not connect to the 5 V plane and actually drill through it, leaving an annular ring of isolation around them.

As a result, this isolation ring prevents the 5 V via on the Bottom from properly contacting the internal plane.

I understand that increasing the spacing between vias would fix the issue, but I’m puzzled why Altium’s Design Rule Check doesn’t flag it as an error.

Are there specific clearance or via-to-plane rules I need to enable so that the DRC detects this situation?

Note: when I select the 5 V plane in PCB view, the via shows the little “cross” symbol indicating a connection, yet in 3D view it clearly isn’t making contact.

Thanks in advance for any suggestions!

QDrives , 07-14-2025, 07:28 PM

Why do you have such big clearance on the plane layer and not so high on the outer layers?

Robert Feranec , 07-15-2025, 04:54 AM

you may need to move the via, or you could move the vias that are around or as @QDrives suggested, you can change clearance on planes.

AmedeoDS , 07-15-2025, 07:17 AM

Thank you all for the helpful suggestions on how to solve the issue, I really appreciate them.
However, my main question was more about why Altium's Design Rule Check doesn't report this problem in the first place, and how I can configure it to do so.
I’d like to understand if there's a specific rule or setting I should enable so that DRC can detect when a via intended to connect to a power plane is actually being isolated due to nearby antipads from other vias. Any insights on this aspect would be very helpful, thanks again!

AmedeoDS , 07-15-2025, 07:24 AM

I found that it is a known problem. https://bugcrunch.live.altium.com/#/bug/22977

QDrives , 07-15-2025, 02:27 PM

Again I am so glad I do not use planes. Just polygons.

Robert Feranec , 07-16-2025, 06:09 AM

hmm, it should report it, interesting