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So i dumbly overlooked an error before sending the PCB into production. A vias that is supposed to be connected to the 3V3 polygon in the power plane is mistakenly connected to the GND polygon in the GND layer

So my question here is, is there a chance to fix this manually once i get the PCB or is contacting manufacturer is the only option (already done, but just checking in case i do not have to use my wallet again)

Thanks

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  • \$\begingroup\$ The vias seem to be insulated from the 3.3V polygon. It doesn't look like there's any problem. \$\endgroup\$ Commented Jun 5, 2023 at 23:48

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First things first, this is should be no issue at all. As Jonathan mentioned in his comment, the vias are not connected to the 3V3 trace, because the PCB software automatically adds a small isolation between the signals. Think about this: People often use an entire middle layer for GND/Supply but they still have vias running through there to connect the other two sides, without shorting any signal.

Now, there are 2 scenarios I can think of that might be an issue in this case:

  • the 3V3 trace has to carry a high current
  • the insulation is too small

If you chose the width of the trace for a specific current but place vias over it, you will effectively cut off part of the trace, increasing the resistance in this place which can, in very extreme cases, lead to destruction. You can see this in your example, where the bottom GND via effectively blocks ~ a third of the whole trace. I don't think this is an issue in your case but it is something you should be aware of.

The second scenario doesn't apply here as well, since the voltage between the signals is only 3V3. But if you have a high voltage trace (e.g. mains voltage or even higher) you need bigger isolation distances. If you are not careful and forget to specify your isolation distances, the PCB program might use settings that are way to small.

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