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The Chosen One , 06-21-2024, 04:54 PM

Just a general question about 4 vs 2 layer PCBs.

If I make a 2 layer PCB and put a polygon pour with a GND net on the top and bottom vs a 4 layer board with 2 GND planes and 2 Signal layers, how are these any different/what are the benefits of the 4 layer board vs the 2 layer board?

André Araújo , 06-21-2024, 07:18 PM

The most beneficial aspect of using GND planes is having a solid trace right below the TOP and BOTTOM signal traces. You don't achieve that using GND fills on the same layer as the signals.

I have designed some 2 layer boards and it is very difficult to achieve proper grounding. It's almost impossible not to cross signals between layers. And then you lose your full signal trace counterpart on the GND fill. You can use vias to mitigate that, but it won't be as effective.

Robert Feranec , 06-22-2024, 05:42 AM

very simply to explain - PCB layout is not only about connecting pins together. Solid GND plane under tracks will help you to keep high quality and clear signals on your PCB, for example it helps to eliminate false interrupts, random board freezing, random resets, random data on buses, ... I have done many videos on these topics, you can start with this https://youtu.be/52fxuRGifLU