Hi all,

I'm planning to use the PIC17c766 in a multi-purpose PC104 form factor
I/O card design.  The PIC has a pair of separate pins for the analog
converter supply.  The datasheet says that the potential on these pins
(AVdd and AVss) should be the same as Vdd and Vss, respectively (and
it's written in bold, so it must be important!).  In order to keep the
analog side clean, I would like to power the micro (digital side) from
the (noisy) +5v switching converter connected through the bus while the
A/D would be powered from a 7805 on the 12v bus.  My concern is that the
magic smoke inside the PIC will escape if one of the supplies drops for
some reason.  Our application is experimental, and so many things could
go wrong.  I'd rather not add a toasted PIC to the list of things to
fix.

Has anyone out there had experience with using a separate supply for the
A/D, and if so, did it work well? (and with what precautions?)

Thanks for any advice available,
Don

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