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Design >> RF Design >> How do I plot gm of RF model?
https://designers-guide.org/forum/YaBB.pl?num=1118825984

Message started by uncle_ezra on Jun 15^th, 2005, 1:59am

Title: How do I plot gm of RF model?
Post by uncle_ezra on Jun 15^th, 2005, 1:59am

I am aware that for regular MOS to plot gm or other intrinsic parameters you can basically follow the discussion in http://www.designers-guide.com/Forum/?board=circuit;action=display;num=1079491622

However, I came upon a weird RF model setup by UMC. I basically do "save:M0" but it does not save any of the intrinsic parameters only the extrinsic RF parameters are saved. I look into dcOpInfo-info and I see that the intrinsic parameters are located in M0.main directory. Can anyone help me how I can save the intrinsic MOS parameters for this RF MOS model? Basically I want M0.main in dc-dc directory as well so a gm vs. vgs plot can be plotted.

Thanks

Title: Re: How do I plot gm of RF model?
Post by Andrew Beckett on Jun 15^th, 2005, 10:37pm

Do "save M0.main".

What is happening here (I expect) is that the model is a subckt, and the device is within the subckt. So you need to give the hierarchical path to the device instance when you do the save.

Often these things are done as inline subckts, which removes the need to specify a hierarchical path - however, if the subckt contains other devices in parallel, the reported current when an inline subckt is used is for the inline device, and not the subckt terminal, and so in that case people tend to revert to a conventional subckt for those types of models.

Regards,

Andrew.