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

[Colin D Bennett <colin@xxxxxxxxxxx>]

On Wed, 25 May 2011 13:11:50 -0400
DJ Delorie <dj@xxxxxxxxxxx> wrote:

> 
> > - 0603
> 
> This is RESC1608N

It's designed for the same component package, but the footprints in pcb
are not identical.

> > - RESC0603L / RESC0603N / RESC0603M
> 
> These are metric :-)

As I said before, not at all confusing.  Surely it wouldn't cause a
million-dollar space probe to crash if imperial/metric is
confused... :-)

Anyway, I have a few more questions then:

(1) Is the SMD package "metric name" commonly used or standardized?
(e.g., 1608 for what is commonly called an 0603 size package). In all my
googling and reading I have only seen the metric names used once, an
that in the Wikipedia article listing package sizes.  All other
guidelines and specifications I've seen call the package "0603", using
the imperial name.

(2) Do you have any experience using the RESC1608M/N/L footprints for
SMD resistors and ceramic chip capacitors?  Have you found that any of
these, or the "0603" footprint work best for general use?  I suppose
the "Most" version would be the most forgiving in assembly and
soldering, and it appears most similar to the "0603" footprint that
I've been using thus far.

(3) What is the correct way to refer to the "imperial" 0603 or the
"metric" 1608?  For polarized capacitors I have seen mention of
packages like "EIA 6032-28" which is a metric specification (package is
6.0 mm x 3.2 mm).

However, I there are references to "EIA 0603" that refer to the
"imperial 0603" package (i.e., 1.6 x 0.8 mm; "metric 1608").

So even prefixing a size with "EIA" is less than helpful.  Must I
always say "imperial 0603", "English 0603", or something?  Or, since as
I said before, the vast majority of references to "0603" are "imperial
0603", that is the de facto standard (except the pcb footprint
RESC1608M series).

Craziness.

Regards,
Colin


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