Re: SOT23 pin numbering

Hello Brad,

    If your PCB Designer has to re-enter anything then they are
responsible for ensuring their version matches yours. So that is
not really a valid concern. ...

That's not quite how I see it. My clients are the main concern. They are my clients as well as the layouter's clients. So together we have to make sure that things pan out nicely. A blame game later helps nobody.

                        ....Like I said, a simple note in the
schematic would suitably put them on notice as to your numbering
convention. If they re-enter the works then they can use any
convention that they want but it is their responsibility to match
your overall netlist.

Which brings up the point that you have to re-generate all the library parts or at least check them one by one. I am using Eagle but it was similar in others: You can find SOT23 and other packages with various pin numbering schemes among library files.

    Using the EBC, GSD, etc. is also fine but myself I hate that
system. Can't say why other than some CAD systems don't support
it or don't support it nicely. It also means that you do have to
maintain a number of identical (physically) footprints. There
again is one of my pet peeves, my current employer requires each
company part number to have a unique footprint identified by the
company part number. What a maintenance nightmare (should I call
it an opportunity? Or maybe job insurance, since there is always
library maintenance to do?).

CAD systems usually do not support EBC. They support 123. Or sometimes 321. The next day you pick another part and it may be 312. So I understand your employer very well. They want to avoid a major pitfall. In some more heavily regulated environments it goes further. Being that specific is law there.

Regards, Joerg

http://www.analogconsultants.com
.

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