Dave asked:

>I'm still getting significant jitter (>5 bits) on *some* input values
>from *some* input sources (remember I have many possible plug-in input
>sources, and their electrical characteristics are unknown for all
>practical purposes), but I haven't yet got a "front end" between the
>input and A/D, that's my next step. Any suggestions for a very low power,
>single supply (5V), rail to rail in/out op amp?
>
TI makes some very good ones; not too expensive either. It's their LINCMOS
line. Comes in singles, duals, quads. Don't have my databooks here at home
with me to find the number. If you can't find it tommorow send me email and
I'll look it up.