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https://designers-guide.org/forum/YaBB.pl Simulators >> RF Simulators >> Spectre simulator and Analysis temparature https://designers-guide.org/forum/YaBB.pl?num=1106674154 Message started by Mahbub Reja on Jan 25th, 2005, 9:29am |
Title: Spectre simulator and Analysis temparature Post by Mahbub Reja on Jan 25th, 2005, 9:29am Jan 25, 20045 Hi everyone, I have a problem with running simulation at different temparature. In the Analog design environment window, I see the Temp=27 0C. If I go to the simulation->Analog-> Temparature options, then I see the following. temp=27 0C tnom= 27 0c If I change the "tnom", my simulation results do not vary. But if I change the "temp" (0 0C to 100 0C), my simulation results completely different than at 27 0C. My question is that how the simulator analysis temp (27 0C) is related with the real world temparature or actual circuit and its devices parameters. How, I can determine, whatever the temparature from 0 C to 100 0C, the simulation results do not change. What is the difference between the actual circuit temparature and the analysis temparature. Best regards Mahbub Reja |
Title: Re: Spectre simulator and Analysis temparature Post by Andrew Beckett on Jan 28th, 2005, 11:04pm I don't really understand your question as such, but perhaps this will help. tnom is the default temperature at which the components in the circuit (i.e. the models) were characterized. This can then be overridden by having a tnom parameter in the model definitions themselves. I suspect this is what is happening in your case, which is why it doesn't make any difference. You wouldn't normally mess around with a global tnom unless you have models without this parameter, and you know they were characterized at some unusual temperature. temp is the simulation or analysis temperature. The models are adjusted using the difference between temp and tnom for that model - although you do also have to take into account that instances may have the "trise" parameter on them indicating a temperature rise from ambient (i.e. the temp you set) - which is a local temperature offset. This all gets further complicated by the fact that some models include modelling for self heating... Andrew. |
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