[sdiy] split ground plane

[Daniel Kruszyna]

I'm working on a pcb with separate analog and digital ground planes.
Is there any special method I should use when routing signals from
one side of the pcb to the other? For example, I have an r2r on the
digital side whose output I want to connect to a level-shifting opamp
on the analog side. Is it ok to just route the signals between the
two planes? Or does this method create a loop on the return path?

In the past, I've only dealt with chips that have separate analog
and digital supplies, which do any necessary interfacing internally.

-- Daniel