Inter-connection Cap v.s. Gate-source Cap

[davyzhu]

Hello all,

I encounter a problem when I use a CMOS model (0.6um, China model) to simulate. My workmate use it to simulate asynchronous circuit. And I found the the calculation equation of the rise time do not include gate-source (or gate-drain) capacitor. I guess the Inter-connection (i.e. between two mos stage ) capacitor outweight gate-source (or gate-drain) capacitor, therefore the Cgs is neglected.

I remember the Cgs is about less than 1pF and how about the normal inter-connection capacitor in 0.6um?

The same question about the two capacitors in 0.18um and 0.13um?

Regards,

Davy Zhu

 

[borodenkov]

which model are you using?

 

[Hughes]

Interconnection capacitance is dependent the layout. It is not included in the mosfet model.

 

[qutang]

it's Cgs,the effect is heavy.