AD7626 interfacing with Zynq or Kintex
Here are the things to consider.

All the IO in one bank must use the same supply voltage.

You must pick a supply voltage for which you are allowed to choose LVDS as the IO standard.

If you have other pins already in an IO bank, then you can only put your LVDS signals on that bank if the other IO is also able to work with the same supply voltage.


To learn more about the IO on the 7-series devices consult UG471.
https://www.xilinx.com/support/documentation/user_guides/ug471_7Series_SelectIO.pdf
Per page 91, the LVDS standard is only available in the HP IO banks when powered at 1.8V, and the VDS_25 standard is only available in the HR IO banks when powered at 2.5V.