Hi Luis, and thanks for the reply.
I posted the issue over in the MCP forums, have yet to get a reply. However, in another post , a user complained that the MCP3911 evaluation board was not producing the data he was looking for. I wonder if the MCP3911 on it was set up to run on the crystal-based clock vs. the MCU-based clock - it's a simple pin header with a jumper... and if the caps are all wrong, who knows if the crystal could even start oscillating?
FWIW, other reference schematics published by MCP (like the one for the tamper resistant power meter) show the kinds of pF load capacitors one would expect for a crystal. But, as with many cost-conscious designs, the power meter eschews the use of a crystal for the MCP3911 itself, using an IO line from the PIC MCU as a clock ticker instead. I suppose that also has the advantage of you being able to vary the clock speed and hence the performance / power consumption of the MCP3911.
Anyhow, for now I am chalking up the crystal load capacitor specification in ADR00398 as erroneous unless someone has a good idea what a 0.1uF capacitor has to do with loading a tiny clock crystal!
Thanks again for the reply. Constantin