SOT23 pin numbering

That's what I meant. I sort of assumed tbat all PCB CADs were as rational
as EasyPC.
You assumed that all PCB CAD packages were as rational as EasyPC. I've
previously used a high-end Mentor Graphics package - retailing for Ł50k
PCB/Ł25k Schematic - that is not as rational and where you did have to
create every combination (or would it be permutation?) of schematic/pcb pin
number mapping. I suspect by the way the way library kept growing that the
powers-that-were, controlling the standard company library, decided to
create new symbols and footprints for every new part - what a waste!

Now if only they'd put in proper back annotation and hierarchical
schematics...
At present I mainly use Pulsonix which is EasyPC's bigger cousin and has
proper back annotation and hierarchical design. I guess WestDev/NumberOne
Systems want to keep the two products separate because of their different
markets and prices.

James
 
Well, yes, that's how mine does it (Eagle). But when you send off to the
layouters and they use another then you can only hope that they carefully
read the notes since their CAD might assume another pin order on the
package (footprint symbol).
Ah! I didn't realise you were using different schematic and layout tools.
I've never been in that position myself but I see where your coming from
now.

James
 
On Fri, 15 Jul 2005 16:34:52 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Brad,

Usually by the time the parts have been properly checked,
you
could have made them from scratch just as quickly. If you don't
believe me just consider what you must do to thoroughly check
them? What do you need to do when creating them from scratch? Not
much difference is there? The actual creation/drawing/placing
time is far less than the detailed measures and calculating the
land pattern geometry.

In Eagle a creation from scratch takes a lot of time, more than it
did
for me in OrCad. But there are easy ways to check things out: Place
all
the components you want to use or where you suspect irregularities
on a
schematic. Connect them in a way that allows easy identification
where
drain, source etc. should be. Switch to "PCB", scatter them on
there,
hit "autoroute" and print it all out. Magnify, so you have an
easier
time to measure against mfg pattern specs.

That all takes just a few minutes but then you know whether the
dimensions are right, pinout is correct etc. Of course, this is
only
time efficient if you use an integrated schematic/layout software.

Regards, Joerg

http://www.analogconsultants.com

To answer your original question, there is no standard. I have done
what others have suggested and created multiple footprints called
SOT23, SOT23B, SOT23C

It is a huge error-prone mess. Every SOT23 in a layout one needs to
verified with a data sheet.
 

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