ethan
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Hi there,
Recently, I frequently met the several repetitive warnings from spectre when I tried to do PSS and PAC simulation. One case is shown in the following. I am wondering whether it will cause inaccurate results and how I can get rid of them. Thank you so much.
I have used "errpreset" with moderate and liberal two cases. the warnig messages are almost same. And maxacfreq=50M; there are two phase non-overlapping clocks in the netlist.
Spectre Log file for the case with errpreset=moderate:
Command line: spectre -env artist5.0.0 +log ../psf/spectre.out +inter=mpsc \ +mpssession=spectre0_4894_5 -format psfbin -raw ../psf \ input.scs spectre pid = 5076
Loading /usr/cadence1999/ic5032/tools.sun4v/spectre/lib/cmi/3.0/libinfineon_sh.so .................. (omitted) spectre (ver. 5.00.32.070703 -- 07 Jul 2003).
Notice from spectre. Includes RSA BSAFE(R) Cryptographic or Security Protocol Software from RSA Security, Inc.
Simulating `input.scs' on anubis at 2:24:33 PM, Mon Aug 15, 2005.
Circuit inventory: nodes 46 equations 97 bsim3v3 12 capacitor 14 relay 18 resistor 19 vsource 8
Entering remote command mode using MPSC service (spectre, ipi, v0.0, spectre0_4894_5, ).
**************************************************** Periodic Steady-State Analysis `pss': fund = 200 kHz ****************************************************
================================ `pss': time = (0 s -> 2.0075 ms) ================================ Important parameter values: start = 0 s, outputstart = 0 s, stop = 2.0075 ms period = 5 us, steadyratio = 1e-03, step = 2.0075 us maxstep = 20.075 us, ic = all, skipdc = no reltol = 1e-03, abstol(V) = 1 uV, abstol(I) = 1 pA temp = 27, tnom = 27 C, tempeffects = all errpreset = moderate, method = gear2only, lteratio = 3.5, relref = alllocal, cmin = 0 F, gmin = 1 pS
pss: time = 50.2 us (2.5 %), step = 11.2 ns (558 u%) ................................................. pss: time = 1.957 ms (97.5 %), step = 237.3 ns (11.8 m%) Conv norm = 45.8e+03, max dV(net064) = -2.45447 V, took 27.71 s.
Warning from spectre during periodic steady state analysis `pss'. pss analysis might be slow because at least 2500 time-steps are needed to meet `maxacfreq' constraints. ====================================== `pss': time = (2.0025 ms -> 2.0075 ms) ====================================== pss: time = 2.003 ms (2.68 %), step = 11.09 ns (222 m%) .................................................................. pss: time = 2.005 ms (50 %), step = 210 ns (4.2 %) Zero diagonal found in Jacobian at `Vswitchp' and `Vswitchp'. Zero diagonal found in Jacobian at `Vswitchp' and `Vswitchp'.
(continued in the next post)
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