Re: design chart (gm/Id) on the wide swing current mirror ck
I think a much bigger issue with the gm/Id methodology, as some already pointed out in this forum, is that it wasn't able to predict gds, and Vds (not Vdsat) well. Take for example, the voltages at node 13 and node 12 are to bias the folded cascode amplifier (not shown), therefore the voltages at node 12 & 13 are fixed to certain values, in order to achieve this goal, I will have to know gds(M12) and gds(M15) [or VDS(12) and VDS(15)] in order to calculate the divided voltage at node 13. I just don't know how gm/id can help me solve this issue, and I don't know how to extend this methodology to cover this gds and vds issues. If anyone can shed some light, I will be very much appreciated.
Thanks,