The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> ron and 1/gds of Cadence Spectre
https://designers-guide.org/forum/YaBB.pl?num=1227866476

Message started by pancho_hideboo on Nov 28^th, 2008, 2:01am

Title: ron and 1/gds of Cadence Spectre
Post by pancho_hideboo on Nov 28^th, 2008, 2:01am

Any expert of Cadence Spectre.

Cadence Spectre give ron and gds as DC operation point of bsim3v3 MOSFET.
Here ron is not eqaul to 1/gds.

What is different between ron and 1/gds ?
If I want to know an estimation of on resistance of drain and source, which value should I use, ron or 1/gds ?

Title: Re: ron and 1/gds of Cadence Spectre
Post by Geoffrey_Coram on Dec 3^rd, 2008, 5:44am

I think ron = vds / id, in some sense the "large-signal" resistance, whereas gds is the slope of id with respect to vds at the operating point.

Title: Re: ron and 1/gds of Cadence Spectre
Post by pancho_hideboo on Dec 3^rd, 2008, 3:55pm

Geoffrey_Coram wrote on Dec 3^rd, 2008, 5:44am:

I think ron = vds / id, in some sense the "large-signal" resistance, whereas gds is the slope of id with respect to vds at the operating point.

Thanks for response.
So ron is suitable than 1/gds for my application.