What is the maximum input power the FMCDAQ2 can tolerate on the analog inputs without something breaking or going non-linear?
The AD9680 datasheet has an absolute max rating of VIN+/- as +3.2V.
This means that the input swing cannot exceed about 4.3Vpp. See below for datasheet excerpt.
From the schematic, you can estimate the insertion loss along the input front end network. Here is an example of how the calculation is done : Who Ate My dBs? | Analog Devices
You should be able to back calculate the maximum allowed input power from the information stated above.
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