My next board will be 4 layers. Top and bottom layers for signals, layers 2 and 3 in the middle for power and ground respectively.
This board doesnt have any high speed signals and no differential pairs. Is it a good practice to fill the top and bottoom signal layers with power and ground after I route all of the signals?
Also, are there some good resources on 4 layer board design?
Thank you.
Yes, but this is Not a Design-How-To-Do-It site… This is a site on how to use Kicad to implement your design.
Sure, we geeks like to help but… some internet searching will go a long way…
In general, more ground is more betterer. Routing power is a secondary objective.
There are several very good youtube video’s about the importance of a GND plane and signal integrity. The best I’ve found yet is a 2 hour long video from Rick Hartley. Those 2 hours are worth watching. That is how important GND planes are.
Also amend that with a few video’s in which a field solver is used to make the electromagnetic fields surrounding tracks visible. After that you will have a pretty good insight of what are good practices (and why), and also what sort of things to avoid.
This for example:
It’s not the switching frequency that counts, but the rate of change of signals. It’s the steepness of the flanks (on digital signals). There is also a huge difference between “hobby projects” in which you only want to make a PCB “that works”, and commercial projects that have to conform to EMC regulations.
there’s another reason, apart from the more the better
Copper pour symmetry is important to reduce / limit board warp during reflow
I can assure you, if you pour 100% on bottom and 10% on top, your boards will be bent like a banana when they come out of reflow.
you might also, if you want to be better with EMI/EMR/EMC is put the traces on the inner layers. Bugger to troubleshoot though LOL
Thanks paulvdh! I watched this video. This is the kind of information I was looking for to get me pointed in the right direction. Absolutely worth watching a few times. So much info packed in two hours nineteen minutes. I also foud a few videos from Phil’s Lab that were good too.
glenenglish, my first PCB curled up after going through the reflow oven for this exact reason. I’m glad that happened becuase now I know not to do that again. 
If you figure that the top layer (call it L1) has the highest density of signals on it, the next layer down (L2) should usually be a ground plane.
The spacing between L1 and L2 ( and between L3 and L4) is relatively close in the usual layer stackup. Layers 2 and 3 usually have more space between them. In pcb layout, stray inductance is most often the parameter to minimize. For that purpose it is best to have a ground plane closely spaced below the top layer with the most critical signals on it.
L3 might have power distribution while L4 would have longer distance/slower/less critical signals on it.
In the switching power converters that I work on, proper stackup and layer assignments can make a big difference in performance, noise, and component stress.
(guy took it down)…abcdefg
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