Inner layer sequence
Posted: Fri Feb 17, 2023 4:12 pm
The last batch of SDU boards that I ordered was unusable because the 5V rail was shorted out. I couldn't find any other explanation then swapped inner layers. By design layer 2 is 5V, layer 3 is GND.
Now, after staring at the gerbers I'm starting to think it must be something else. Vias go all the way through and if a layer is etched away around the via it doesn't make contact, if it isn't etched, it does make contact. Shouldn't matter where the layer is in vertical order or am I missing something?
Here's the GND layer (layer 3) recognizable by the connection to the wifi modules thermal pad
And here the 5V layer NOT connected to the thermal pad
I have ordered a batch of 5 boards of that same design before and they worked normally.
Now, after staring at the gerbers I'm starting to think it must be something else. Vias go all the way through and if a layer is etched away around the via it doesn't make contact, if it isn't etched, it does make contact. Shouldn't matter where the layer is in vertical order or am I missing something?
Here's the GND layer (layer 3) recognizable by the connection to the wifi modules thermal pad
