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Topic: Is it common for the same part to have different pin-outs? (Read 2061 times) previous topic - next topic

nickgammon

I was working with a 2N7000 MOSFET. I have a couple of datasheets on my hard disk, so I grabbed the first one I could and found that it disagreed with the pins as actually measured with a parts tester. Then I found the second datasheet had different pinouts. See below.







Note the different order of gate, drain, source for the TO-92 part.

Is this common? I would expect that different manufacturers, of the same part number, would use the same pin-outs.

(You may need to open the images in a separate window to see the clearly. RH-click and select "View Image").
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More info: http://www.gammon.com.au/electronics

michinyon

It seems to me,   the leads on the TO-92 are the same in both photos.

If you turn the second photo over, so the flat side is facing down,   then the order of the leads is the same D-G-S in both of them.

pantaz

Looks the same to me. Just the pictorial representation is flipped between the pages. (Flat side up on ST's sheet, flat side down on Fairchild's.)

Edit: michinyon beat me to it!

nickgammon

Not at all. In one of them the source is the middle pin, in the other one it isn't. No flipping is going to change that.
Please post technical questions on the forum, not by personal message. Thanks!

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MorganS

The ST datasheet shows the source is pin 2 of the SMD part but it's pin 1 on the through-holer. They should have drawn those boxes vertically so that the numbers on each package belong only to the schematic directly below it.
"The problem is in the code you didn't post."

nickgammon

Oh I see. Well, the Fairchild diagram is much less open to error of interpretation.

The concept of putting 1/2/3 on the actual pins, and then having them described below, when they could just as easily have printed S/G/D is quite a silly one.
Please post technical questions on the forum, not by personal message. Thanks!

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runaway_pancake

The concept of putting 1/2/3 on the actual pins, and then having them described below, when they could just as easily have printed S/G/D is quite a silly one.
I've been at this for a long time, Nick.
There was once a "convention" where the pins were presented as though looking through the device, with x-ray eyes, from overhead.
"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

cmiyc

The concept of putting 1/2/3 on the actual pins, and then having them described below, when they could just as easily have printed S/G/D is quite a silly one.
Agreed.  Likely done so that they only have 1 set of pictures used in all datasheets with those packages.  Easier for them, harder for the customer.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

michinyon

On your ST datasheet there ,   the 1,2,3 on the first diagram matches the lettering on the second diagram,  for the corresponding device.

michinyon

So,  if the datasheets are actually the same,  then the "different datasheet" theory is actually a red herring ;  how does that explain Nick Gammon's apparent experience with the actual device then ?

nickgammon

What confused me was that I saw 1/2/3, my eye dropped to the SOT23 part, and read off 1 = G, 2 = S, 3 = D, without noticing that on the TO-92 part the numbers corresponded to different leads.
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

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