Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)

[Gabriel Paubert <paubert@xxxxxxx>]

On Wed, May 25, 2011 at 07:11:49AM -0700, Colin D Bennett wrote:
> On Wed, 25 May 2011 06:41:26 -0700
> Colin D Bennett <colin@xxxxxxxxxxx> wrote:
> 
> > (1) Why is RESC0603L/N/M much smaller than '0603'?
> > (2) Why is there no similarly named set of RESC0805L/N/M for 0805
> > size? (3) Why does RESC1608M nearly match the '0603' footprint?
> >     Is there an imperial/metric naming confusion happening?  I thought
> >     0603 was a standard name for this size.
> 
> I think I've answered some of this for myself... from Wikipedia's
> âSurface-mount technologyâ article:
> 
>     01005 (0402 metric) : 0.016" à 0.008" (0.4 mm à 0.2 mm)
>     0201 (0603 metric) : 0.024" à 0.012" (0.6 mm à 0.3 mm)
>     0402 (1005 metric) : 0.04" à 0.02" (1.0 mm à 0.5 mm)
>     0603 (1608 metric) : 0.063" à 0.031" (1.6 mm à 0.8 mm)
>     0805 (2013 metric) : 0.08" à 0.05" (2.0 mm à 1.25 mm)
>     1206 (3216 metric) : 0.126" à 0.063" (3.2 mm à 1.6 mm)
> 
> So the source of the confusion over footprints is that '0603' is a valid
> name for both a metric and an imperial size.. both different?  Whoever
> decided to name the packages that was must have been on crack.

Indeed. I found a set of recommended footprints that distinguishes
resistors from capacitors: 

http://www.ibselectronics.com/pdf/pa/walsin/smt_notes.pdf

I have used it quite successfully, including for long edge
capacitors (0612 or 1632 metric) and 4 resistors in a single package 
(4x0603 or 4x1608 metric). I also took into account the recommendations 
on page 10 when ordering the stencil, shrinking a bit the solder paste
apertures generated by PCB.

	Regards,
	Gabriel


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user