I know it's not appealing to write one's first post in an RF focused group talking about DC but please bare with me :)
I am interested in plotting some MOS DC parameters like gm, gmoverid, Cgg, gds as they vary across VGS and VDS.
Keeping VDS fixed for the moment, I would expect to be able to DC sweep VGS and get a curve of - say - gm Vs. VGS. This is not the case. I actually get only one point, which is the point corresponding to the "static" value of VGS, in the design variables list.
Of course I could set up an equation in the Calculator for the derivative of Id but I think that "somewhere" the tool should calculate those parameters for me...And also because for some trickier parameters like Cgg the whole process would be more complicated.
The alternative to that is to run a parametric analysis, but this is way less effective timewise.
Does anybody know of a way of overcoming this?
Thank you in advance,
The key is that you're using the OP() function, whereas I said to use the results browser. The OP function will retrieve the DC operating point data, not the results from the DC sweep.
If you do that, and send the signal from the results browser to the calculator, you'll get something like this:
getData("M1:gm" ?result 'dc)
And this should plot the gm versus the swept variable for the dc analysis. You could also just type the getData() expression into the calculator.
There is an enhancement request (for some time) requesting an easy way to set up these save statements and access the results from the UI, but it's not been implemented yet.