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https://designers-guide.org/forum/YaBB.pl Modeling >> Semiconductor Devices >> Hspice conversion https://designers-guide.org/forum/YaBB.pl?num=1049951926 Message started by kimsm on Apr 9th, 2003, 10:18pm |
Title: Hspice conversion Post by kimsm on Apr 9th, 2003, 10:18pm Hi, Ken I have some question about spectre format. I want conversion of hspice format sub-circuit into spectre format sub-circuit. As I know spectre is not support V(n1,n2) (voltage-drop of n1-node and n2-node). Below equation is hspice format circuit : >> .subckt nmos_rf nd ng ns nb lr=length wr=width nr=finger >> m0 nd ngi ns nbi nch w="wr*nr" l=lr ad=0 as=0 pd=0 ps=0 >> rgx ng ngi "(127.02+(86.55*lr*1e6))/(nr+1.9) + (-0.22+2.5*lr*1e6)" >> cgd ngi nd "((0.45+1.5*lr*1e6) + ((1.06+0.89*lr* 1e6)*nr))*1e-15" >> cgs ngi ns "((-9.74+73.05*lr*1e6) + (0.97+1.57*lr* 1e6)* nr)*1e-15" >> cjd nd nbi "(((7.81-16.2*lr*1e6) + ((0.29+4.78*lr *1e6)*nr))*1e-15)/pwr((1+(v(nd,ns)/0.6791)),0.3529)" >> cjs ns nbi "((-7.46+3.34*nr)*1e-15)" >> rsubx nbi nb "(12.67*nr+1954.1)/(nr+8.26)" >> .ends lvn I want to conversion functions above, is possible? send your opinion, please... i'll wait. good bye Best Regards ;D |
Title: Re: Hspice conversion Post by Ken Kundert on Apr 9th, 2003, 11:18pm First, create a file for the subckt. I called it lvn.m. You can call it whatever you like. Code:
Next, create a Verilog-A file for the nonlinear capacitor. I called it nonlincap.va. Code:
There are two issues that you need to be aware of with this model. First, Cjsx will be negative if nr < 2. That would be bad. It would generally result in making the circuit unstable, which would cause the simulator to fail. Second, in the nonlinear capacitor, the capacitance becomes negative when V(ps,ns)<-alpha. Again, that is bad. -Ken |
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