For help, Modeling Varactor

[angelina]

I am using Cadence to simulate a LO circuit which include a off-chip varactor from Philip, but I don't know how to creat a model of this varactor in Candence. I only know the formula to calculate the capacitor of this varactor. Thanks for any heip!
C=Cj0÷(1+V/VΦ), Cj0=23.129pF, VΦ=2.4894V

 

[flushrat]

c_varactor n1 n2 'cj0/(1.0+v(n1,2)/vphi)'
.param cj0=23.123n vphi=2.4894

btw, this equation for varactor is not accurate.

 

[angelina]

i don't know how to build a model for this off-chip varactor in Cadence according to its formula.

 

[flushrat]

i don't know how to build a model for this off-chip varactor in Cadence according to its formula.

add the above two lines to your netlist

 

[angelina]

i don't know how to build a model for this off-chip varactor in Cadence according to its formula.

add the above two lines to your netlist

Could you explain to me how to add to netlist step by step ?

 

[flushrat]

Could you explain to me how to add to netlist step by step ?

1 In ADE, generate netlist for you testbench circuit
2 Edit your netlist, and add the following:
c_varactor n1 n2 'cj0/(1.0+v(n1,n2)/vphi)'
.param cj0=23.123n vphi=2.4894
n1 n2 are the two terminal nodes of your caractor
replace the equation with a more accuracy one if you have.
3 then run simulation