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Want to get Id vs.Width curve in cadence, but ...

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zizzbear

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Hello ,

I want to do a simple simulation on one CMOS device, to see the Id vs. Width of device,

I set the width as a variable, then sweep it in DC analyze, but in the outcome curve, there is no sweep of width at all. Only one dot appeared, on the Width value where I set as a base value for operation point...

what I am doing wrong? Can I use it in this way , by cadence?

Thank you !
 

dick_freebird

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You may have to use the Parametric Analysis tool and
step, rather than sweep, the width. Then use Calculator
to plot the op(Mx,id).
 

R00KIE

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I'm don't have much experience doing that but one thing I can say, you need to provide a little more info, like the schematic you are using to test.

Maybe that is the problem, if you don't have the proper setup you cannot see what you want to see.

Also just one dot may indicate a simulation problem, check the simulation log.
 

oermens

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create a model file (.scs extension) and include the line

save * sigtype=all

include this file in after your existing model files, and make sure save operating point is on during dc
 

zizzbear

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Hi, all , thank you very much for all your suggestions !

But I am really ashame to tell that , my problem is wrongly setting the sweep step size .

The sweep range for the width is 250nm to 50um, but the step size is still 0.01( the normal one when I do voltage DC analysis.. ), I should use something in nm range.

After change that, it works .

But really very thanks for all your help!!

best rgds!
 

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