Re: Low noise IF3601/02 don't meet specs

In message <dp3vna0tnu@xxxxxxxxxxxxxxx>, Winfield Hill
<Winfield_member@xxxxxxxxxxx> writes
> gm = 123mS is not so high, for a large JFET. Remember, a BJT
> has 200mS at 5mA. InterFET says the IF3601 has gm = 750mS at
> Idss (Vgs = 0) = 30mA min. Note, 750/6 = 125mS, and that may
> be conservative, because gm/Id drops as Id approaches Idss.

That 30mA is Idss min, with no max given. However, data on the
source chip is given on *** NJ3600L, which shows a possible
Idss range of 50mA to 1000mA.

NJ3600L also has graphs of the manufacturing spread of Gfs versus
Vgs(off) and Idss, measured at 10V and 20mA. The Gfs figures
given there are compatible with those being seen by Fred.B.

That Interfet data *** is reminiscent of an old Siliconix barn door.
--
Tony Williams
.

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