How to calculate total gate capacitance of an NMOS

[skamthey]

gate capacitance

Hi,
i m having a TSMC File.
How can i calculate Gate Capacitance for an NMOS. :?:

 

[varma_cs012]

how to calculate capacitance

You are talking about pre-layout or...post layout....??

 

[antonio_eda]

how to calculate gate capacitance

Gate capacitance == oxide capacitance = Cox[per area] * Weff * Leff. This is the gate capacitance of the intrinsic MOSFET, I think?

 

[seddik]

calculate gate capacitance

in your model files you can see the capacitance values per unit of area.
so it depends on the process, your Nmos size and which one you'r looking for.

 

[pbs681]

calculate gate oxide capacitance

in your model files you can see the capacitance values per unit of area.
so it depends on the process, your Nmos size and which one you'r looking for.

look for cgso, cgdo and cgbo value... also translate tox to get cox..... to get details explanation refer pls refer to BSIM3 manual from Berkeley website

 

[littlej_zju]

cox gate capacitance

You can use the temperate function to get those capacitance by hspice.
As I know, please use LX18(nmos) for gate capacitance.
Remember, adding .option dccap=1