Hi,
I'm using a FET in triode and I'd like to plot its Rds vs. Vgs for different Ws. To do that;
I'm sweeping Vgs in DC analysis and changing Ws with parametric analysis tool. The output is the Rds with the expression of "(1/OP("/M1" "gds")
However this setup does not give me multiple Rds versus Vgs curves for different W sizes as expected.
My guess is; in order to plot the Rds, I should do a setting so that simulator saves the op point of the FET during DC sweep. I don't know how/where I can do that.

Could you please help me with that?

thanks
eng

Hi eng,

If you're familiar with MDL, you can do this conveniently with two nested foreach loops
Code:

alias measurement Rds_vs_Vgs{
...
run dc (...)
...

export real Rds=(1/(M5:gds))
// To get Rds of the device
}
foreach Vgs from swp(start=.., stop=.., step=..) {
		  foreach W from swp(start=.., stop=.., step=..) {
		   }
}
run Rds_vs_Vgs
 

Check out the forum posts on MDL for some idea on this.

Good Luck!

Gau