Hi, I'm using Calibre PEX and Cadence Spectre to do post-layout simulation of an OPAMP. I'm using Charterd 0.35um technology. The pre-layout simulation is alright and i also passed LVS. But the Post-layout simulation is not correct, the biasing point of these transistors looks weird.
Take a current mirror for example: MP10 and MP0 forms a current mirror, (W/L)10=(30um/3um) and (W/L)0=(120um/3um),MP10 have 3 fingers while MP0 have 10 fingers. In post simulation the id of MP10 is (-8.37424u*3)about 25uA but that of MP0 is (-33.6371u*12) over 400uA, this really puzzles me since their Vdsat are the same and they are all working in saturation, i think the id of MP0 should be about 100uA. Can anbody help me? Thank you