SOT-23 pin numbers

[Simon]

I need to label pins on a component in KiCAD that is a SOT-23 package. Only thing is I don't know what the standar numbers are on the actualy package. Any pointers ?

[ElektroQuark]

It depends.
Some packages label the pins like 1,2,3... others in, out, gnd...
So, make the module yourself and label it like the component manufacturer. You will have a particular, not generic, SOT-32.
I do it all the time with KiCAD.

[Simon]

yes but i need to know which pins on the footprint have what number. Yes I have a datasheet that does not give pn numbers but shows a 3D model and labels the pins but then I don't know on the pysical package what number each pin is so I can corelate them from schematic to layout, at the moment I am missing the ratsnest on all of my transistors

[ElektroQuark]

Ah! What transistor is it?

[Simon]

2N7002 (sot version of the 2N7000), but the transistor is irelevant, it's the standard pin out of the sot-23 case I'm after

[ElektroQuark]

It's not irrelevant. I have seen identical named transistrors from various makers with diferent pinouts, so the SOT-23 pin numbers are not fixed.

[Simon]

oh great, what happened to great old standards. ok sonow the question is what pinout does KiCAD assume for SOT-23 packages ?

[djsb]

Try this link

http://www.supertex.com/pdf/package/K1_03_TO236ABx.pdf

HTH

David

[Simon]

thanks, most useful - hits the nail on the head 

[RayJones]

It's not irrelevant. I have seen identical named transistrors from various makers with diferent pinouts, so the SOT-23 pin numbers are not fixed.

Indeed, this practice has been around for a very long time.

Take the venerable 3055 NPN power transistor - I've seen them in all sorts of pinouts, especially the TO-220 format (and the larger cousins)

Assume Nothing!

[Simon]

Yes I see the point and have double checked the layout. In the days of the 2N3055 cad design was in it's infancy and that particular part was probably never soldered to a board. These days to have different pin numbers for the same footprint package will create mayhem and hours of work toing and froing from schematic to PCB layout through datasheets making sure all parts with more than 2 pins follow the same conventions we thought were to be followed