Good point. I do have a very low-current measurement problem. I'm trying to characterize cells in a microfluidic channel by the change in resistance of the channel. I think I'll just buy a USB isolator and keep it on the outside of my box.
I do have one more question. I will definitely run off of batteries. One could use a 3V CR2032 coin cell. Another possibility is 3 NiMH batteries, each 1.2V for a nominal 3.6V supply. (at least, until the batteries run down). Is there any advantage to running the ADuCM350 at 3.6V, as opposed to 3V? That is, isn't everything regulated down to 1.8V inside the ADuCM350? I read through the docs, but had some trouble sorting out exactly how the A/D output's full scale range is set.