I am trying to generate a plot of one of the capacitance values generated by captab. My approach is as follows:
1. Use stimulusFile to include the instruction: Cap_dcInfo info what=captab detail=nodetonode sort=name threshold=0 where=logfile
2. Set up captab analysis: Analysis( 'dc ?captab t ?detail "nodetonode")
3. Run parameteric analysis across voltage to generate multiple cap. tables:
paramAnalysis( "vdd" ?start vstart ?stop vstop ?step vstep)
This seems to work when I only run step 2 and 3 meaning I see the multiple cap. tables in the spectre.out file. However, I am having trouble figuring out how to plot a specific capacitance value from the generated tables with the independent variable being "vdd". Although an example exists in a previous post /forums/p/21764/1309486.aspx, it does not include the stimulus used and it did not attempt to plot multiple values but rather only print a single value.
Any help will be greatly appreciated.
A better discussion would be to look at /forums/t/20426.aspx?PageIndex=2(although that's more to do with seeing it over time)
You don't really need to use stimulusFile to turn on captab. Just do steps 2 and 3, and then if you do:
you'll see all the available outputs. You can also access it from the results browser and then send to the calculator to find the right expression. For example:
pv("out : net9" "Total" ?result 'captab) ; don't need the ?result bit if you've used selectResult first
The second arg for pv could be "Variable", "Fixed", or "Total". Because it was a parametric sweep, you'll see the capacitance value versus your swept variable.
In reply to Andrew Beckett: