I've been reading more about proper grounding techniques and using ground planes.
From what I've read, ground planes provide a large capacitance with adjacent layers, faster heat dissipation, and reduce ground inductance.
The one area I'm particularly interested in is the stray/parasitic capacitance created. As I understand it, this is beneficial for power traces but potentially detrimental to signal lines.
I've read a few suggestions about where to place solid ground planes, and I was wondering if these are good recommendations to follow and what would constitute an exception to these suggestions:
- Keep ground plane under power traces/planes.
- Remove ground plane from signal lines, particularly high speed lines or any line susceptible to stray capacitance.
- Use ground guard rings appropriately: Surrounding high impedance lines with a low impedance ring.
- Use local ground planes (same goes for power lines) for IC's/sub-systems, then tie all grounds to the global ground plane at 1 point, preferably near the same place the local ground and local power lines meet.
- Try to keep the ground plane as uniform/solid as possible.
Are there other suggestions I should take into consideration while designing the ground/power of a PCB? Is it typical to design power/ground layout first, signal layouts first, or are these done together?
I also have a few question about #4 and local planes:
- I would imagine connecting local ground planes to the global ground plane might involve using vias. I've seen suggestions where multiple small vias (all in roughly the same location) are used. Is this recommended over a single larger via?
- Should I keep global ground/power planes beneath local planes?