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Simulators >> Circuit Simulators >> Hspice capacitance calculation error
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Message started by Analog_Designer on Nov 1^st, 2012, 1:03am

Title: Hspice capacitance calculation error
Post by Analog_Designer on Nov 1^st, 2012, 1:03am

Hello!
I'm working with the 65nm technology. While i was characterizing the technology by calculating the extrinsic capacitance i got the following probelm:

In the operating point output file the values for cgtot differs from that calculated at the same bias while doing the sweep on vgs.

It's, not only, the cgtot that differs but also all the capacitance values are different in the operating point file than that i get from the vgs sweep.

Any suggestions?

Thanks in advance.........
Ibrahim

Title: Re: Hspice capacitance calculation error
Post by raja.cedt on Nov 1^st, 2012, 3:05am

what do you mean by same bias, while doing .op, you will set some current and Vgs, but while sweeping vgs you can't maintain same current and if you maintain same current Vgs should change.

Thanks,
Raj.

Title: Re: Hspice capacitance calculation error
Post by Analog_Designer on Nov 1^st, 2012, 3:35am

The same bias means the same vgs and vds by letting the cursor refer to the same vgs and the vds is constant