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Pak00 , 05-17-2017, 06:23 AM

Hello,

I have a question about pour GND on 2-layer PCB. Specifically, I mean embedded system board. The main part is uC like STM32, AVR or another 8/32bit uC, maybe sometimes FPGA. Standard interfaces UART,SPI,I2C,USB (no very high speed). Some power supply system. Rather standard PCB. So what is the best way to pour GND on this kind of PCB? Does it make sense to pour GND on the TOP and BOTTOM layer? Is no a better option pour GND only on BOTTOM layer and try to put signal and supply tracks on the TOP layer ? I know that best to use 4-layer PCB but in the amateur's projects often the cost of 4-layer PCB it's too big. I would be very grateful if anyone could explain to me which method is better and why that is. I would like to understand which method is correct.

Thanks, Pak00

mairomaster , 05-17-2017, 07:14 AM

With such boards I don't think you are getting too much benefit from having a pour on the top layers. I would leave it on the bottom only, and use the top purely for routing.

robertferanec , 05-17-2017, 03:46 PM

I agree with @mairomaster, as big GND plane as possible on the bottom layer. This may help you: Doing Layout – Lesson 7 – Learn to Design Your Own Boards

Pak00 , 05-17-2017, 11:25 PM

Thank you for your replies. Often in DIY projects, GND is pouring on top and bottom layer, that's why I had doubts. Now I know that this is a mistake.

mairomaster , 05-18-2017, 01:44 AM

I would say a mistake, but just unnecessary in most cases and just being too much of a hassle to work with.

robertferanec , 05-18-2017, 07:57 AM

and I would maybe also add, everybody is doing it because ... everybody is doing it