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Measurements >> RF Measurements >> ft measurement
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Message started by panditabupesh on Feb 13^th, 2006, 1:18pm

Title: ft measurement
Post by panditabupesh on Feb 13^th, 2006, 1:18pm

Hello
I am doing ft measurement on an nmos. The device is biased with a changing vgs (varying parameter) and fixed vds- using sp and parametric analysis in spectre I am able to do a ft vs vgs plot. However, now I want to do a ft vs ids plot (ids is varied by changing vgs)- is there some way I can probe the dc device current while doing a sp analysis.

-bp

Title: Re: ft measurement
Post by ACWWong on Feb 13^th, 2006, 3:55pm

i'm not quite sure why you are doing sp to get the ft... its much easier to do simple ac sweep, for which terminal currents for the gate and drain are simply available in spectre...

anyway to make idc the variable in the parametric, what i have done in the past is put the idc in the source and bypass it with a cap, so it shorts at high frequency... or bias off a mirror (with mirror reference diode connected and drive with Idc) and use an inductor choke to bias the gate.