A working model for the 2sk170 (basically one half of 2sk389) is available together with the
commercial simulation software HSPICE from Avant!. Unfortunately I cannot post it here because it is
proprietary information. But if you have a chance to get your hands on a HSPICE installation you
will find it in the library directory.
The device is made by Toshiba. But they do not have a spice model for it on the web page.
There are some models floating around out there that seem to have a very small lambda, and can be extremely misleading. The models also make a very abrupt transition from the so-called triode region to the pinchoff region, and comparison to characteristic curves on the Toshiba datasheet show marked discrepancies.
Another difficulty with parameter measurements is the signal-induced self-heating of the parts. One can deal with this using low-duty-factor pulsed measurements, or a strategy that I'm exploring where data sets for a given temperature are acquired when the device has come to ~equilibrium, and sets are recorded keeping the sample isodissipational. This still takes time, but not as long as changing voltages/currents and waiting each time for stabilization.
Thanks Nelson! I guess I've never visited Cordelland --- I'll seek it out.
I did just create another model borrowing from the post above, and it still predicts a way-low output conductance (about 38uS) compared to a linear fit to the Toshiba datasheet curves for Vgs = 0 (closer to 94uS). But it gets closer at least.
I have enough parts that I could even get some decent statistics. Of course they would apply to that particular run/date code. When Harman was shutting down a project (the rule there rather than the exception!) they were allowing people to take away some of the obsolete inventory, and I got a whole bunch of 2SK364BL, which is the same chip as the 170 but characterized for analog switching.
PS: found the site, found the models, but only see now 2 parts for JFETs: both Linear Integrated Systems ones, the LS844 and the LSK389C. Had there been an SK170 before (I know the 389 sections are close but not afaik identical)?