The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> RF Simulators >> Plotting Ft vs Id
https://designers-guide.org/forum/YaBB.pl?num=1334055206

Message started by vaidy.ts on Apr 10^th, 2012, 3:53am

Title: Plotting Ft vs Id
Post by vaidy.ts on Apr 10^th, 2012, 3:53am

Hi,
I have a Cadence ADE schematic with voltage sources vg and vd (I am simulating a MOSFET). Vg is varied and at each Vg, frequency is swept and Ft is calculated. In the calculator, I am able to specify and plot Ft vs Vg and Id vs Vg, but not Ft vs Id. Can anyone help me with this?
Vaid

Title: Re: Plotting Ft vs Id
Post by boe on Apr 16^th, 2012, 8:58am

Hi vaidy.ts,
Plot both and use Id as x-axis.

Does this help?
- B O E

Title: Re: Plotting Ft vs Id
Post by vaidy.ts on Apr 16^th, 2012, 11:13pm

Hi BOE,
I tried, but I couldn't figure out how to plot versus the dependent variable Id. The calculator seems to implicitly use the sweep variable Vg as the x-axis. Lets say I have two sub-plots Id-Vg and Ft-Vg. If it is not too much of a trouble could you explain in words how to do it.
Thanks,
VTS

Title: Re: Plotting Ft vs Id
Post by boe on Apr 17^th, 2012, 10:41am

Hi vaidy.ts,
The calculator always plots versus the independent variable (in your case Vg).

You should plot both curves in one sub-window; then you should look for parameters/attributes of the x-axis. There, you should be able to select vs. which waveform you want to plot.

Does this help?

- B O E

Title: Re: Plotting Ft vs Id
Post by sheldon on Apr 24^th, 2012, 5:52am

Vaid,

Here is a link to a detailed discussion of how to perform the
measurement. In addition, there are other appends that cover
the details of how setup the simulation properly and how to
measure fmax.

Best Regards,

Sheldon

http://www.cadence.com/Community/blogs/rf/archive/2008/08/09/simulating-mos-transistor-ft.aspx?postID=10665