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J111/J112/J113 pinout confusion

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Fancy Lime:
Hi there,

I had some trouble getting J113 switches to work and after some debugging I went back to check it I may have remembered the pinout wrong. So I looked it up only to find two different pinouts for the TO-92 package in datasheet from OnSemi. The 1997 datasheet, still published under the name Fairchild, says DSG, whereas the 2020 datasheet, which does not mention Fairchild anymore, says GSD. Sure enough, I thought the ones I used were the latter but really were the former. I'll have to check the others I have and see what's what. But really the question is: WTF? Anyone else had that problem?


I thought it was just me being an idiot (I mean, I was and am, but it's possibly a separate issue in this instance), but I recently fried about three J111s just trying to test them for Vp/Idss because I was evidently working off the wrong datasheet myself. I didn't keep track of which datasheet was correct and which one wasn't, but I seem to recall that the J111s turned out to be GSD in reality (which matches almost all my other JFETs, which is the only reason I remember). I had got them from Mouser last summer, I think.

I'm glad to know that I'm not the only one!

(But I still blame myself for not keeping notes after frying the first one to prevent myself from doing it again...)

OnSemi datasheet marked
"Publication Order Number: J111/D March, 2006 − Rev. 2"

shows TO−92  CASE 29−11  STYLE 5, which is what we'd expect for a J series fet,

"Publication Order Number: MMBFJ113/D September, 2020 − Rev. 3"

shows TO−92 3 4.825x4.76  CASE 135AN [and case 135AR]

and it seems that hanging "3" covers the confusion, as it's pins the other way round. you would have to hope that suppliers were across this.

Rob Strand:
I'm very skeptical of the correctness of modern datasheets, for old or new parts.   

My paper copy of the 1983 Motorola databook shows,

  \ d  s  g/  when viewed from the bottom.

It's a TO-92 package, Case 29 Style 5.  Style 5 is pin 1 drain, pin 2 source, pin 3 gate;  \ 1 2 3/ as viewed from the bottom.

I have noticed the disagreement in the J111/J112/J113 pinouts on the various pdf datasheets.

FWIW, Motorola became On-semi long before Fairchild was taken over.

Mark Hammer:
This is why I keep saying, only half tongue in cheek, that you'd think there wouldn't be quite so many pinouts for FETs and bipolars with only 3 pins....but you'd be wrong.  I find the best thing to do is to do an image search for the specific transistor, in order to see if there is a 3D drawing.  I can never tell if the other drawings are looking down on the transistor or up.


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