Pin out's for SOT-23's do change from manufacture to manufacture!  but in general that isn't the major
problem I have had with them in the past.  Not only do the pin numbers change but the devices that are
packaged in them vary too much!  Diodes, Transistors etc.  in one package the gate is pin 1 the drain pin 2
and the source is pin 3 in another it's different, and yet another manufacture with the same device pin out
is different still.  I am sure that several standards organizations have tried to define this but when the
manufactures create the silicon they are more concerned about function then fitting the package.

In general I have seen these package pin-outs the most but as stated above its anyones guess when it comes
to the pin function
---3---
-1---2-
SOT-23-123

---1---
-3---2-
SOT-23-321

If you have the ability to define these devices on your schematic and the layout use pin numbers instead of
alpha characters to define the pins.  123 is easier to check then GDS or BCE.  The Layout library part
should be also numberic.

I hop this has helped

Mike Gish
Ditron Manufacturing, Inc.

Dee Stover wrote:

> Is there an SOT pin numbering standard?  I hope it isn't like through hole
> stuff and all are different from manufacturer to manufacturer and sometimes
> part to part within mfrr.
>
> DIPS are
>
> 1       14
> 2       13
> 3       12
> 4       11
> 5       10
> 6       9
> 7       8
>
> SOT 23  (P = pad)
>
>         P                       1                       3
>
>        P             P                   2            3         1       2
>
> or the SOT 223
>
>         P                       1                       4                       1
>
>       P       P       P                2       3      4                1       2
>    3           2      4       3
>
> Does anyone say this way is the way we are going to do it no matter what
> the manufacturer data sheet does?
>
> I hope the pin positions came out on the email.
>
> Thanks,
>
> Dee Stover  [log in to unmask]
> National Optical Astronomy Observatory
> 950 N Cherry Ave
> Tucson, AZ 85719
> 520-318-8489
> FAX 520-318-8303
>
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