I am trying to run a Monte Carlo simulation of a 25GHz LC-VCO (vco followed by an ac-coupled buffer) for phase noise (mmsim-7.11, pss (harmonic balance) and pnoise). When I try a single run (no variability), the simulation finishes successfully without any errors or warnings. When I try running a Monte Carlo simulation (with process and mismatch), I am having one of the problems described below randomly (depending on the seed and starting run#). By the way, when I try to run a transient analysis in a Monte Carlo simulation with the same samples, the simulation finishes successfully. Could you please help?
1) After the first few samples, the simulator stops/freezes without any error messages in the output log.
2) At the first sample, I got the error message: "ERROR SPECTRE-16192: No convergence achieved with the minimum time step specified". I think this happens during the tstab. However the transient simulation does not have any convergence problems with the same set of samples.
Could you please help?