8-pin DIP pinout for JFET?

I have a schematic showing a part identified as J412, which is probably a National Semiconductor NJFET. The schematic only shows the pin numbers, not the JFET symbol itself, so I can't guess the pinout. I suspect there might at one time have been a generic 8-pin DIP pinout for JFETs, but I can't confirm this. Or I could be wrong about what a J412 is. Of all things, it's part of an ancient solid state guitar amp.

Reply to
Bearded Occam
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There was an LF412 dual jfet op-amp -

1 out a v+ 8 2 - in a out b 7 3 in a -in b 6 4 v- in b 5

I don't have any J412 in my databooks, and the J parts I do have are TO92/SOT-23 FETS. There is a dual FET in 8 pin layout for a completely different series of FETs, but see if it makes any sense with your schematic (the NC's might help):

S G D NC NC D G S

Note the package can be put in backwards and still work.

--
Cats, coffee, chocolate...vices to live by
Reply to
Ecnerwal

I'm pretty sure that that's an old Siliconix number. But the Siliconix discrete book that I have doesn't have the datasheet, or the datasheet for the part that's given as equivalent, U412. (Usually J parts are plastic, and U parts with the same number are the same thing in TO5 or some other metal can).

Looking in an old GE Intersil book, they don't have the J412 either, but do say that the IT502 is an equivalent. But they say the U412 is equivalent to the 2N3958.

Now it gets confusing. The IT502 is a dual cascode amp (2 sets of cascode amps each with 2 JFETS), while the 2N3958 is just a dual JFET.

One place to look is Vishay, as they took on the Siliconix discrete parts lines.

(I also vaguely remember somebody posting about the J412 for an oscilliscope repair, a year or three back).

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Reply to
Mark Zenier

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