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  3. Spectre: Missing nodes in the operating point report. A...

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Spectre: Missing nodes in the operating point report. A configuration issue or a simplification?

AF202602026942
AF202602026942 22 hours ago

I am using Spectre 23.1.0.594 to save the operating point of an AMS simulation, but there are nodes that do not appear in the generated report.

 

Current settings:

simulator lang=spectre

global 0 psub2! vdd! vss!


simulatorOptions options preserve_inst=all savefilter=none iccheck=no psfversion="1.4.0" temp=27 tnom=33 scale=1.0 \
scalem=1.0 reltol=1e-3 vabstol=1e-6 iabstol=1e-12 gmin=1e-12 gmindc=1e-10 rforce=1 \
maxnotes=5000 maxwarns=50000 digits=5 pivrel=1e-3 checklimitdest=both highvoltage=yes\
max_minstep_nonconv=1000 negative_cap_opt=no fix_zero_diagonal=yes \
soa_warn=yes soa_dest=file check_format=text

//Operating Point for Floating Nodes Analysis
tran tran stop=1 errpreset=conservative skipdc=no cmin=0.1f \
write="spectre.ic" writefinal="spectre.fc" method=gear2only \
relref=sigglobal annotate=status maxiters=100 \
compression=wildcardonly compreltol=0.00001 complvl=1 compvabstol=0.01e-3 compiabstol=1e-9 \
infotimes=[3250u] infonames=[ic_snap]

ic_snap info what=oppoint optype=ic where=file file="snapshot.ic" save=all nestlvl=100

finalTimeOP info what=oppoint where=rawfile
modelParameter info what=models where=rawfile
element info what=inst where=rawfile
outputParameter info what=output where=rawfile
asserts info what=assert where=rawfile

Problem observed: On reviewing the snapshot.ic file, I notice that certain nodes are missing.

 

Suspicion: I wonder whether Spectre is performing some sort of automatic simplification (for example, with identical devices in parallel using the m-factor; many of the missing nodes correspond to this scenario) which is causing not all nodes to be reported individually.

 

Questions:

  1. Is there a save option or setting I’m missing that would allow me to capture these nodes?
  2. Does Spectre simplify or group certain nodes/devices when saving the operating point?
  3. Is there an option to force all nodes to be saved without any simplifications?

 

I’d appreciate any guidance or suggestions.

 

Thank you!

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