Ken Kundert
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The first thing to do is to ignore all of the advice Cadence gives on setting the tolerances tighter than the default. I have used SpectreRF since before it was released, and I always start the default tolerances and they are sufficient almost all of the time. Most to the time when people complain about convergence, I strip off the tight tolerances and the convergence problems go away. And the simulation run much faster.
Second, keep an eye on the convergence norm. If it drops steadily until close to one (one represents convergence), but then stalls, it suggests that your tolerances are too tight.
Third, make sure your circuit is periodic. The easiest way to do this is to turn on strobing and strobe at the period of the fundamental frequency. If you then plot the strobed waveforms they should become constant valued. If they don't, if there is some noise or oscillation, then your circuit is not periodic and PSS will not converge.
Fourth, increase tstab. If you have plotted the strobed waveforms, set tstab to the time when they are close to being constant valued.
That is the process I use, and I very rarely have convergence problems with SpectreRF.
-Ken
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