Favorite Threads and Posts in "Pass Labs"

flg

Member
2005-07-06 1:13 am
North East
SemiSouthFan: Not that I know of. SemiSouth did not produce one and my research group has not needed to produce one either. A SJEP120R100 SPICE model could be modified with a little scaling.

But truthfully, none of these models do a good job with the curvature of the output characteristics (ID vs. VDS) near saturation, a problem no one has been able to fix using the core SPICE JFET model. So predicting amplifier linearity with the available models is not recommended. It is ironic that the gradual "knee" or transition to saturation of the output curves for the R100 was viewed by the power switching community as a curiosity indicating lack of maturity in the channel design. Silicon power MOSFETs have sharper transitions, which is a major reason, in my analysis, for why the IRF parts deliver higher THD than the SemiSouth JFETs. What is one man's poison is another man's nectar.

Gee, I could be a poet.

For power switching, modeling near saturation is not really needed so it just hasn't been a priority, despite a few tries with only partial success. I have a need for modeling the transfer curves at the corners of the safe-operating-area (i.e., at hundreds of volts on the drain) and a student will finish a Master's Thesis on this improvement soon. But DIY Audio folks don't operate in that part of the device SOA, so I would say the available models are mostly useful for checking the basic functionality of a dc bias circuit because threshold and transfer curve modeling at low drain voltage is pretty good, and maybe some general guidance on AC operation, but not much more.

If there becomes a bigger demand, I might arrange for work on the near-saturation model to see if we can make this a better representation of the true characteristics. Maybe as an undergraduate research project.
 
Yes.
It is the last year.
There never-ever will be more.

Papa probably bring us on the diy bench big static induction transistors.
Get curve traced & matched 2SK180 pair's and hope for article in near future.
 

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