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Simulators >> Circuit Simulators >> DC solver failed
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Message started by vijay on Nov 3^rd, 2005, 8:54pm

Title: DC solver failed
Post by vijay on Nov 3^rd, 2005, 8:54pm

Hi friends,
I am trying to simulate a maneatis symmetric load.While trying to simulate for its dc OP, spectre says A2=0 and Pcdibl2= negative.
This is a cpnvergence error as i see it.
setting the options for gmin convergence also does not help.
Looking out for suggestions.
Thanks in advance,

Title: Re: DC solver failed
Post by Andrew Beckett on Nov 4^th, 2005, 5:13am

a2 and pdiblc2 (I assume that's what you meant) are bsim3v3 and bsim4 model parameters. I'm assuming it's complaining about these parameters being out of range.

Since you gave no useful information about what exactly the error was, it's ahrd to be sure. Perhaps you're simulating with device sizes which are too large? Can't really tell... it would have helped if you'd posted the exact error message.

Regards,

Andrew.

Title: Re: DC solver failed
Post by Geoffrey_Coram on Nov 14^th, 2005, 8:21am

I've seen warnings like those before; I think some foundries set values for these parameters that seemed "unlikely" to the people who implemented BSIM3 in Spectre. The warnings don't come from the original Berkeley code, as far as I know. But as Andrew said, they're model parameters, and the warnings really don't mean anything as far as convergence of the circuit.