DoctorX
Joined: 02 Sep 2004
Posts: 73
Location: USA
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 18 Sep 2004 7:18 Re: how to get varactor C-V curve in CDS? |
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| pigkiller wrote: |
| Since I have a varactor with two terminals ,Gate and "Source+Drain",how to get varactor C-V curve in CDS?pls be more specific |
Hook up (wire) the varactor properly with all needed grounding and biasing sources, to facilitate measuring of its input impedance with a current ix. Give the Vbias voltage source a variable name of "Vbias", do ac analysis, instead of sweeping frequency, sweep Vbias, then use your calculator:
Cap = 1/Impedance(f0)/(2*pi*f0)
There may be a direct way of plotting Cgg capacitance, but I kind of forget without looking at Cadence right now.
Yes, if your concern is that after adding Vbias, you short out the ix, you can put a large (dummy) inductor (say 100 H) in series with the Vbias.
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