I am using Cadence IC5141 and running a simulation which requires the ".IC" setup for inductors. I tried to put some value under the "initial condition" field of the inductor, but the value is going when I doubly confirmed it with the transient analysis. Are there anything that I may miss or the initial condition of the inductor does not work at all? By the way, are there any alternative way to figure this out? Thanks a lot in advance.
I'm not sure what you mean by "the value is going". You might want to clarify.
Whether initial conditions on devices is controlled by the ic parameter for tran analysis, or the force parameter for dc. This defaults to all for tran, and none for dc. It needs to be dev or all for the initial condition to be used.
By the way, you didn't specify which simulator you're using. What I'm talking about above is for spectre. The fact you're talking about ".IC" suggests to me you might be using a different simulator?
Thank you very much for your reply and sorry for the confusing.
What I really mean the value is going is the following:
1. I set the inital current of the inductor as 1mA. Later, I run the transient simulation, and the inductor current at t=0 is zero.
2. I did try to set "dev" and later "all" under the trans analysis, but none of them work.
3. I am using "spectre"
Thanks again and hope that helps.
Is this an inductor from analogLib? Or from some other library? Perhaps the other library has a field for initial condition but doesn't netlist it, or doesn't use it? I tried this myself and it does work...
If you have a simple small testcase, can you paste the input.scs here?
I am using the inductor in analogLib, and here is the input.scs testing file. Thank you again for your help.
// Design view name: schematicsimulator lang=spectreglobal 0
// View name: schematicV1 (net38 0) vsource dc=1.8 type=dcR1 (net31 net15) resistor r=1KR0 (net30 net13) resistor r=1KC2 (net30 net31) capacitor c=300f ic=-30mC1 (net13 net15) capacitor c=100f ic=300mL1 (net38 net31) inductor l=70nL0 (net38 net30) inductor l=70n ic=500uic net13=0.35 net30=-40m
simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=27 tnom=27 scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 digits=5 cols=80 pivrel=1e-3 sensfile="../psf/sens.output"checklimitdest=psf tran tran stop=0.001m errpreset=conservative maxstep=100p ic=all write="spectre.ic" writefinal="spectre.fc" annotate=status maxiters=5 finalTimeOP info what=oppoint where=rawfile
modelParameter info what=models where=rawfileelement info what=inst where=rawfileoutputParameter info what=output where=rawfiledesignParamVals info what=parameters where=rawfileprimitives info what=primitiveswhere=rawfilesubckts info what=subckts where=rawfilesaveOptions options save=allpub
I just tried this, and plotting L0:1 (the current through the inductor):
As you can see, the current starts off at 500uA.