SOT-23 N-FET package with source and gate reversed

Thread Starter

Richiek67

Joined Jan 26, 2022
3
Hi ,

Just wondering if there is an N-FET sot-23 package on the market that has the source on pin 1 and gate on pin 2?
Usually its the other way around but the designer reversed this by accident.

Many thanks

R
 

dl324

Joined Mar 30, 2015
14,462
Yes, well, that's the last choice if there's no available part
If order enough parts and pay a setup fee, the manufacturer would probably make some with the pinout your engineer designed for.

You do realize that there are a large number of different MOSFETs, so anything matching the pinout you need might not be what the circuit needs. If you start talking to manufacturers, make sure you use the proper device name because there are many different types of FETs. When I see FET, I think JFET.
 

du00000001

Joined Nov 10, 2020
100
Hi ,

Just wondering if there is an N-FET sot-23 package on the market that has the source on pin 1 and gate on pin 2?
Usually its the other way around but the designer reversed this by accident.

Many thanks

R
Fortunately all MOSFETs I know have no variations on the pinning. Fortunate for me, unfortunate for your designer.
Suggest to glue the FET in the dead bug position and do some fancy wire soldering :)
 

jrb_sland

Joined Dec 24, 2021
6
Ha, No, I suggested that to the engineer already and its not an option unfortunately...but thanks...
This is a wonderful example of why we should all pay very, very serious, quiet & careful attention to pinouts when creating parts inside our favourite schematic-capture/board-layout software. IMHO, you are now committed to redoing the card layout, but only AFTER you fix the FET pinout confusion, and DELETE the wrong part from your libraries. One hopes you haven't already spent serious money on a big batch of erroneous boards. BTW, it is your engineer that needs to revise his parts - don't do it yourself - let him fully experience the consequences of being sloppy. But don't feel too badly about this - we have all done it, but hopefully only once. We learn best from our mistakes...
 

du00000001

Joined Nov 10, 2020
100
This is a wonderful example of why we should all pay very, very serious, quiet & careful attention to pinouts when creating parts inside our favourite schematic-capture/board-layout software. IMHO, you are now committed to redoing the card layout, but only AFTER you fix the FET pinout confusion, and DELETE the wrong part from your libraries. One hopes you haven't already spent serious money on a big batch of erroneous boards. BTW, it is your engineer that needs to revise his parts - don't do it yourself - let him fully experience the consequences of being sloppy. But don't feel too badly about this - we have all done it, but hopefully only once. We learn best from our mistakes...
Wrong approach: never make a designer review his/her own work. This is exactly how errors slip.
A reasonable review process (anything else is just a waste of time) involves at least one 2nd person with an independent mindset.
 

jrb_sland

Joined Dec 24, 2021
6
Wrong approach: never make a designer review his/her own work. This is exactly how errors slip.
A reasonable review process (anything else is just a waste of time) involves at least one 2nd person with an independent mindset.
Thanks for your reply. You are precisely correct - no-one can proof-read their own work. I was only suggesting that the engineer in this story should spend HIS time fixing HIS goof before he hands it off for proofing. Consequences are best felt by the individual closest to the error. My apologies if I didn't make that clear enough. The whole team on this project need to consciously revise their design review process. Getting things fully correct in our business requires serious attention to detail, and if you're not at least a little OCD you are in the wrong job...
 

MrChips

Joined Oct 2, 2009
26,099
Once I laid out an MCU board and got all D0-D7 data bits swapped!
That was the days before real CAD and schematic capture.
 

jrb_sland

Joined Dec 24, 2021
6
The same happened to me. Wouldn't have mattered for a RAM, but it was at the EPROM .
For the first version, the colleague wrote a small software to swap bits.
And I did much the same in 1983, but deliberately to facilitate the layout. Bishop Graphics sticky pad sets & cyan/magenta tape on thin mylar sheet taped to a light table with a translucent tenth-inch grid. The good old days {LOL}... But it then took me several days to work up a Forth program to do the address bit rotations for the EPROM holding my lookup/translate tables & so on. Never again! Win some, lose some.
 

k1ng 1337

Joined Sep 11, 2020
538
Backwards pins reminds me of Seinfeld's bit about biting down on a fork - hard to imagine someone could do that with all their biting experience haha.
 

du00000001

Joined Nov 10, 2020
100
And I did much the same in 1983, but deliberately to facilitate the layout. Bishop Graphics sticky pad sets & cyan/magenta tape on thin mylar sheet taped to a light table with a translucent tenth-inch grid. The good old days {LOL}... But it then took me several days to work up a Forth program to do the address bit rotations for the EPROM holding my lookup/translate tables & so on. Never again! Win some, lose some.
I only had the data lines connected numbered the wrong way. Resulted from having the auto-increment/-decrement of Orcad SDT set to the non-appropriate mode (which was absolutely correct previously when connecting the address lines).
Small error, considerable impact. Rev. 2 was significantly better then :)
 
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