How to find out the Vth or the operating region of a transistor

[Deepon]

I have attached a file which explains how to find out the region of operation of a transistor in the older version of Cadence. I am currently using IC5141 version, but using the same procedure doesn't seem to work. Does anyone knows?

View attachment ECE418SaturationGuide.pdf

 

[pavel_adameyko]

Hai
I would rather recommend you to look at relations between Vgs and Vds to determine the region then rely on what Cadence tell you

 

[erikl]

I have attached a file which explains how to find out the region of operation of a transistor in the older version of Cadence. I am currently using IC5141 version, but using the same procedure doesn't seem to work. Does anyone knows?
View attachment 54923

At least it works well with a DC analysis, including backAnnotation into schematic.

 

[palmeiras]

Hi Deepon,

Use menu Resuts, --> Print DC operation points.
Or, Results --> Annotated DC operation points. But in this case, you need to include the parameter "region" to be annotated too. (Menu edit component Display).
Regards,

 

[hoangtruyen]

Hi,

The best way to get exact Vth value is finding it in model with "VTH0" key word.

 

[Deepon]

okay.. I'll try that...

 

[dgnani]

Vth0 is not the exact Vth because it does not include any second order effects, the exact value depends on the operating conditions and has to be checked with OP analysis. Using schematic annotation would be the practical way to do it - see palmeiras post