2 layer or 4 layer PCB

SteveW719

I am designing a small board with a xbee pro and a prop chip and a few periphels. It is small around 2"x2". Should I make a 4 layer board with Gnd plane and power plane in the middle and signal traces on the outer layers? If it is better for noise immunity and the radio circuit I can justify the expense. If it will not really make any difference I would go with a 2 layer. Not very many components so routing either way should be possible. It is just going to operate some SS relays remotely.

I should say I am pretty new to laying out PCB but I have been studying the copper pour (DIPTRACE)and think I understand that pretty well. If I make it 2 layer should I pour a Gnd plane around all the traces on the top and bottom?


Thanks
Steve

Leon

If it's a one-off for your own use it doesn't matter much. If you aim to sell it you need to pay a lot of attention to EMC matters.

Phil Pilgrim (PhiPi)

If you're new to PCB layout, you will find it much easier to design a four-layer board, since you don't need to worry about power and ground routing and can concentrate on the signal traces. They are more expensive, though.

-Phil

schill

Using the power and ground planes embedded inside the board makes it a lot harder to make changes or fix mistakes after the boards have been produced. You can't just cut traces going to power and ground connections when they are vias.

Granted, most errors are probably for other connections but this makes even changes as simple as connecting an LED pin to power instead of ground difficult (not that I've ever had to do something like that ).