First of all, Andrew and Ken, your help is much appreciated!
Incredible: it works! Although even when I disable all the flicker noise sources, there remains something at DC that causes the crash. Maybe it's the integrating nature of a relaxation oscillator?
I suspect this integrating nature will cause more problems; a PSD with a delta function in its origin doesn't seem hopeful on a computer. Maybe this causes the warning about the inaccurate Floquet eigenvectors? The noise results consist of huge values near DC..
I initially thought about the Verilog-A models as being the origin of the crash, because while using the previous version of one of them, I got a crash during PSS:
Quote:======================================
`pss': time = (11.25 us -> 11.4613 us)
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pss: time = 11.26 us (2.67 %), step = 528.2 ps (250 m%)
pss: time = 11.27 us (7.67 %), step = 528.2 ps (250 m%)
pss: time = 11.28 us (12.7 %), step = 528.2 ps (250 m%)
pss: time = 11.29 us (17.7 %), step = 528.2 ps (250 m%)
pss: time = 11.3 us (22.7 %), step = 528.2 ps (250 m%)
pss: time = 11.31 us (27.7 %), step = 528.2 ps (250 m%)
pss: time = 11.32 us (32.7 %), step = 528.2 ps (250 m%)
pss: time = 11.33 us (37.7 %), step = 528.2 ps (250 m%)
pss: time = 11.34 us (42.5 %), step = 528.2 ps (250 m%)
pss: time = 11.35 us (47.6 %), step = 311.9 ps (148 m%)
pss: time = 11.36 us (52.6 %), step = 168.3 ps (79.7 m%)
pss: time = 11.37 us (57.5 %), step = 221.6 ps (105 m%)
pss: time = 11.38 us (62.5 %), step = 234.3 ps (111 m%)
pss: time = 11.39 us (67.5 %), step = 304 ps (144 m%)
pss: time = 11.4 us (72.5 %), step = 411.2 ps (195 m%)
pss: time = 11.41 us (77.5 %), step = 528.2 ps (250 m%)
Time steps are continuously to be extremely small.
Conv norm = 11.9e+06, max dV(I14:idt0) = 1 V, took 300 ms.
PSS failed to converge. PSS will adjust tstab a little and try again.
======================================
`pss': time = (11.25 us -> 12.1303 us)
======================================
Internal error found in spectre at time = 11.25 us during periodic steady state
analysis `pss'. Please run `getSpectreFiles' or send the netlist, the
spectre log file, the behavioral model files, and any other information
that can help identify the problem to support@cadence.com.
Assertion failed in file `devices.c' at line 4587.
Assertion failed.
I'm using a small capacitor to overcome the hidden state problem of PSS (its voltage models a binary state variable). Just when
Time steps are continuously to be extremely small, this variable is set by charging the capacitor through a small resistor; a too small resistor. By increasing this time constant a bit, PSS analysis converged successfully. Possibly interesting for others as well!
Thanks again,
Paul
P.S. Possibly the answer to one of my previous questions could provide me insight?
Quote:What are the 'necessary and sufficient' conditions for PNoise (and LPTV analyses in general) to give accurate results?