[sdiy] OT: Linux pcb and SMT?

[Colin Hinz]

On Sun, 2 May 2004, Jay Schwichtenberg wrote:

> Howdy,
>
> Does anyone out there know of a SMT library for pcb under Linux?
>
> Also does anyone know of where you can find the specs for various SMT
> pads/packageing?

It's always best to refer to the individual datasheets. There are
*numerous* SMT packages out there which appear to be the same but
are not quite compatible. This seems to be a problem with QFP's
in particular.

In theory, there are IPC component standards, but since few (if any?)
of the IC datasheets make any reference to them, I'm not sure if
there's any use in obtaining them (btw, the IPC standards cost a
fair amount of money -- or at least they did a few years ago).

The only "sure bets" are resistors and capacitors -- even a lowly
SOT-23 transistor can be a source of layout trouble, as there
seem to be at least two pin numbering schemes in existence.

- Colin Hinz
  Toronto, Canada