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cmin in analog option and pss option

Hi,

I find cmin can be specified in both analog/option and pss/option. If both of them are defined, which is high priority, or which will over-write the other?

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Richard25PLL over 2 years ago

I think pss option is of higher priority. Maybe you can try to give them different values and then check the log file to see which value gets chosen.
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Richard25PLL over 2 years ago

I think pss option is of higher priority. Maybe you can try to give them different values and then check the log file to see which value gets chosen.
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ShawnLogan over 2 years ago in reply to Richard25PLL

Dear sjwprcker,

sjwprcker said:
I find cmin can be specified in both analog/option and pss/option. If both of them are defined, which is high priority, or which will over-write the other?

Just to add to Richard25PLL's comment as I thought a few more words might help....

It depends on the simulation you are performing. When cmin is specified for a pss simulation, the netlist will include a pss runline something like this:

pss pss fund=1G harms=10 errpreset=moderate cmin=10f

Therefore, during a pss analysis it will honor the value of cmin specified within the pss simulation command. If you are not performing a pss simulation and specify a value for cmin through the "analog/option" as you note, then the transient simulation runline in the netlist will appear something like this:

tran tran stop=100n errpreset=moderate write="spectre.ic" \

writefinal="spectre.fc" annotate=status maxiters=5 cmin=10f

Hence, in my understanding, there is really not a "conflict" (and hence priority) between the value of cmin you select in a transient and pss analysis. Each analysis uses the value you select for each.

There are some scoping rules for the use of cmin in a transient simulation that have relative priorities. If you need to specifiy a value of cmin for a node or subcircuit, you might want to take a look at the article at URL:

https://support.cadence.com/apex/techpubDocViewerPage?xmlName=spectreuser.xml&title=Spectre%20Classic%20Simulator,%20Spectre%20APS,%20Spectre%20X,%20and%20Spectre%20XPS%20User%20Guide%20--%20Parameter%20Specification%20and%20Modeling%20Features%20-%20Specifying%20cmin&hash=pgfId-262907&c_version=21.1&path=spectreuser/spectreuser21.1/chap5.html#pgfId-262907

Shawn
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