[Magic-dev] Spice model effects

[R. Timothy Edwards]

Dear Peter,

> T54G SPICE BSIM3 VERSION 3.1 PARAMETERS.  I then take the same
> extraction and substitute an older (~ six years) spice model.  This older
> model old and has far fewer parameters than the T54G model.  
> The former model gives a factor of five faster circuit. The transistor
> dimensions appear to be set in the extraction.  Does the model scale
> the layout?  Is something fundamentally broken.
> We have a good deal of experience with the older models and
> have no reason to doubt the results that we got with them. 

Without seeing the spice decks, my gut feeling is that it's a scaling
problem, possibly due to the format written vs. the format read by the
simulator.  Magic extracts to hspice or spice3 format.  The hspice
format uses a scale option that is not available in spice3.  spice3
output should give all units in absolute numbers.

					Regards,
					Tim

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