I am designing a wide ICMR diff amp. To realize it, I made pmos diff pair as well nmos diff pair. The idea here is, for lower values of ICMR, pdif pair will conduct and for higher values of ICMR ndiff pair . My question is, from the outputs of pdiff pair and ndiff pair how should I make the single ended output.
I used a similar design in my LVDS receiver,i.e, have both NMOS and PMOS input diff amps. After that you may have to use a max current selection circuit to select the max current from either the NMOS or PMOS.
For more information you can see the following link and download the receiver design paper.