Sorry in advance for the newbie question, but I can't seem to find a good answer. Recently, I've gotten into printed circuit boards and it is all still fairly new. I'm working towards creating a 4 layer pcb and I'm curious common practice for layer stack up. I've seen some places that use the outer layers as signal layers and internal two layers as GND and VCC and vice versa other places.

Is there any stack up for a four layer board (or any amount of layers for that matter) that is particularity advantageous?

Also from previous research it seems that having both a GND and VCC plane creates a small amount of capacitance, why is this useful?


I generally try to keep my signals on the outside layers and planes on the internal layers, though this is highly dependent on the design. Having capacitance between two planes is advantageous because it provides a little bit of immunity to noise on the supply line that could otherwise couple into the circuit. Sometimes you may want to shield traces carrying sensitive signals, in which case you might put those on an internal layer and put grounds on the external layers. There really isn't a one-size-fits-all answer - it is highly dependent on your particular design and what signals and components you have.

This is why it is very helpful to have a firm understanding of electronic systems and how environmental factors and parasitics affect signal quality when designing PCBs. Without this knowledge and understanding you're effectively taking a shot in the dark at whether or not it will work as expected.

I can't seem to find a good answer

This is because the "good answer" will be different for every design for different reasons.


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