Ground pour

[ican7]

I would like to use copper pour on top and bottom of the pcb and connect them to the ground net. I have low and high current tracks as well as differential pairs. Do I have to set different polygon clearance settings for each track thickness?

[robertferanec]

We normally use a gap 0.2mm - 0.5mm between polygon and other signals / polygons. Depends on how much space we have. We usually use one type of gap, preferably the bigger one (0.5mm). But I guess, other people may use it different way, you can use even a bigger gap.

[ican7]

Hi Robert, Thank you for your response. In terms of EMI, can you please elaborate why do we use the same value clearance for the ground pour through out the board ? Also how can I determine if the the value you have given is best for my application?

[robertferanec]

I do not pour ground on signal layers as I am not convinced about effectivity of doing it and I think, in some cases it may cause problems. So I prefer to use solid GND plane. The gap I explained before is normally used between power planes or high current nets and other signals/planes.