[SOLVED] [Spectre calculator] How to calculate input capacitance of a 2 ports network.

[ktx2222]

Hi everyone,

I am a newbie in Cadence spectre simulator. I have a 2 ports network and I try to plot the input equivalent capacitance vs. frequency. In ADS I use equation: Cin = imag(Y11)/2/pi/freq. But I don't know how to insert that equation into Cadence. I only used a basic SP analysis. I have read many thread but I cannot find the answer.

Please give me a detail instruction. I really appreciate your advice.

 

[sarge]

Hi, i usually measure cap with ac analysis in cadence, but your way is also working

So, i've created cellview:




ADE window -> Tools -> Calculator

value(imag(ypm('sp 1 1)) VAR("Freq")   )/(twoPi*VAR("Freq"))

You can place just freq value instead of VAR("Freq").

That's my result:

1.001E-12

 

[ktx2222]

Hi Sarge,

Thank for your help. Now I can get the discrete value.

Anyway, I have one more question: Can I do it with a range of frequency? Because I think most of circuit has the input capacitance depends on frequency. So I want to plot the Cin in a range of frequency.

 

[sarge]

if you want to plot frequency dependence of it in sp:

imag(ypm('sp 1 1))/(xval(imag(ypm('sp 1 1))) * twoPi )

 

[ktx2222]

Thank you so much, sarge! It really help me.