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Modeling >> Passive Devices >> Capacitor simulation
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Message started by gorkhim on Sep 28^th, 2008, 5:44pm

Title: Capacitor simulation
Post by gorkhim on Sep 28^th, 2008, 5:44pm

I am trying to estimate the equivalent series resistance, quality factor and capacitance for a MIM capacitor in 90nm process technology using S-parameter analysis in Cadence IC5141.

After running the analysis, I am using the Y-parameters to plot the G, C & Q using the following equations:

1. G = real(Y11 - ((Y12*Y21)/Y22))
2. C = -imag(Y11 - ((Y12*Y21)/Y22))/(2*pi*f)
3. Q= -imag(Y11 - ((Y12*Y21)/Y22))/real(Y11 - ((Y12*Y21)/Y22))

The plot for these equations is attached. These plots are not making any sense. Does anyone have any clue about what am I doing wrong?
Also when I use a similar test-bench for an inductor, these equations works properly

Thanks.

Title: Re: Capacitor simulation
Post by Berti on Sep 28^th, 2008, 11:58pm

Unfortunately, your graphic is hardly readable.
However, are you sure that the MIM capacitor model includes a series resistance.
In the DK I am using, the no series resistance is modeled for the MIM capacitor, unless
you add it from parasitic extraction.

Regards

Title: Re: Capacitor simulation
Post by gorkhim on Sep 30^th, 2008, 1:59pm

Thank you for your quick response. Yes there was wrong model file.

Title: Re: Capacitor simulation
Post by ywguo on Dec 12^th, 2008, 1:29am

Hi gorkhim,

Why do you measure the Q/G/C with 2 ports. It is one port for a varactor actually. The formula is simpler if simulating with one port.

1. G = real(Y11)
2. C = imag(Y11)/(2*pi*f)
3. Q= imag(Y11))/real(Y11)

Yawei