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DC convergence issues with vcvs used in a bandgap circuit

uzzymoh

Hello,

I am trying to simulate a simple version of the bandgap circuit shown in the attachment below. I am trying to use the VCVS (voltage gain=1303) as the error amplifier in the bandgap circuit. But, it is having severe dc convergence issues. The circuit just does not converge. The moment I remove the vcvs and instantiate a real (transistor based) error amplifier, the circuit converges fine. Could any of you help me with this if you have come across this issue ? Also, I tried changing iabstol, gmin, nodeset, pivotdc and various other recommendations by the spectre simulator when it fails to converge. It was of no help. Even the most simplified version of the schematic which is what I have attached does not want to converge.

  • Using the +diagnose switch in usrCmdLineOptions in Setup->Environment might help a little (although that mostly helps with transient convergence/performance issues), but I think the best solution here is to go to customer support so that we can look at this with you. Figuring it out from what you've posted is close to impossible.

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