[sdiy] Analog & Digital Ground

[Seb Francis]

Hi,

I'm just laying out quite a large board which is almost all analog, 
except for a PIC&opto for the MIDI interface.

Normally I have totally separate analog and digital grounds which are 
joined right the way back at the PSU (at the end of the power lead), but 
in this case the PSU is on the same board.

I am thinking that I should separate the PIC&opto ground from everything 
else with a ferrite bead.  The power is already separate (it has its own 
5V regulator).

Does this sound sensible?  Also, should I hook the 5V regulator to this 
digital ground as well?  And perhaps even connect the power input to the 
5V regulator via another ferrite bead?

Thanks,
Seb