ad=0 and pd=0 when extract netlist with RC by Calibre xRC @ the mos drain and source connected together. however as& ad have the correct value.
why can that be? Could anyone can give me the explaination? Thanks!
ad=0 and pd=0 when extract netlist with RC by Calibre xRC @ the mos drain and source connected together. however as& ad have the correct value.
why can that be? Could anyone can give me the explaination? Thanks!
"ad=0" and "ad have the correct value" is a contradictio in adiecto, so it's probably a typo, I guess (and you thought of "as & ps have the correct value"?)
For some irregular but - concerning source & drain - symmetric MOS structures, some extraction rules just extract area and periphery of (e.g.) the source, double these values and set ad & pd =0 , which still leads to a correct capacitances' calculation. Just check your exraction rules.
See also this topic, and perhaps this one for ring or waffle MOS structures.