I am designing 12 bits asynchronous sar adc 10Mhz sampling frequency and I am done with the layout and it works good with pex but C only (I mean that I extract only capacitor not resistance) but when I tried to extract RC pex the enob became worse about 2 bit less so I am asking what will affect my enob I mean these resistors added by extraction or what?
... when I tried to extract RC pex the enob became worse about 2 bit less so I am asking what will affect my enob I mean these resistors added by extraction ...?
I didn't try to reduce the frequency but ok I will try. I plot the input of the comparator and I saw that it settled correctly so I think it is not settling issue.