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Confusion regarding captab output ( Drain & Gate ; Gate & Drain)

RFQuery

Dear All,

I was trying to find out the Cgd value of a MOS.

I did cpatab dc analysis.

But I am confused as it is showing two differnent values for Drain-&-Gate capacitance & for Gate-&-Drain capacitance.

The more confusing is :- It is showing difference in the Fixed value capacitance. How physically it is possible ?

What is the Cgd value indeed ?

Could anybodyplease tell & clarify regarding this.

I have attached the cap-Table.

  • I believe this is a consequence of the fact that they are partial derivatives and that one is referred to V(d) and one V(g) - see the explanation in cdnshelp (run cdnshelp from <MMSIMinstDir>/tools/bin/cdnshelp and then search for "captab"; there's a section  "Printing the Node Capacitance Table" which explains things a bit).

    Regards,

    Andrew.

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