Stitching vias

[joniengr081]

I have found some text regarding stitching via. I am wondering how about if the two reference planes are power planes with different voltages on them. Can we also use stitching via between them if a signal is routed over the split ? How about if we have 1.8 V and 3.3 V as reference power planes ?

Can this be two ground planes ? for example analog ground plane and digital ground plane ?

In case they are power and ground plane then it's fine to use de-coupling capacitors. But how about if both of them are power planes or both of them are ground planes ?

[nctnico]

In case of ground planes, you can stitch the ground planes together. The construction in your image is used when a high speed signal travels across planes with different voltages on them. If you go between 1.8V and 3.3V, then you'll need a capacitor between 1.8V and 3.3V.

[joniengr081]

What if the ground planes are separated on purpose. For example analog ground and digital ground ?
 What if the two reference planes are power planes ? I guess we can't connect capacitor between them 

[tszaboo]

Separating grounds is no longer the recommended method, since the 90s. Unfortunately it still pops up sometimes as a recommendation but it is not good for EMI or accuracy. The only reason to separate it if you are dealing with very high currents. 

[joniengr081]

Current is low but I think this is to isolate digital switching in high speed design from analog reference ground.