While experimenting with the v6 FMC and my application, I found that the +/-0.5V range was not quite enough voltage range for me, but the +/-5V was too much, as noise was too high. I found an undocumented +/-1.0V (2Vpp) range

Below is a table of which switches would be enabled for each of the 3 documented ranges, and I found a 4th range using switch settings = 0x64 which implements a +/-1V, or 2Vpp range. The noise level is the same as 1Vpp range, but has 2X the range, so SNR is 6 dB better than 1Vpp. There did not appear to be any change to the bandwidth or any other compromise. I submit this as an issue ticket for consideration in case the documentation could be updated, or perhaps there is a good reason why this switch configuration was not considered previously. Comments welcome.