Are a JFET's Idss and Vgs(off) values correlated?
I know that many JFETs parameters have a very large manufacturing spread, in particular, $I_{DSS}$ and $V_{GS(off)}$, as one can see (for example) in this datasheet excerpt:
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My question is if the spread of these two parameters are somewhat correlated, that is: do we know whether part specimens with higher (in magnitude) $I_{DSS}$ will also have higher (in magnitude) $V_{GS(off)}$?
Or can we have any combination of $I_{DSS}$ values vs. $V_{GS(off)}$ values?
Bonus points if the answers are not only based on referenced statistical data, but also explains why the correlation exists (if it does), e.g. by mentioning factors in the manufacturing process that cause the correlation to exist.
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I'll let someone else answer about the device physics. I'll answer from an electrical engineering standpoint.
The answer is: Maybe, but it doesn't matter since you should be considering worst case in your design anyway.
You are really asking whether there is any correlation between the gate voltage to allow 10 nA, versus the current at 0 gate voltage. There is probably not a direct relation in the physics, but maybe a general trend. Again, none of this should matter when designing a circuit with these parts. If you want more definite specs, then you need to select individual parts yourself, find a different part that guarantees the parameters you need, or change the circuit to be more tolerant.
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