One additional thing that I believe is important regarding the 7351 v 782 issue, is
the acceptance by the international (read european (actually read "IEC")) community
of 7351, whereas it is my understanding that this is not and never was the case with
782. This issue is important now, and will become even more important in the future,
in expanding our (read USA) markets, and allowing us to integrate, design wise, into
a more internatioinal community, where, among other things, we will be able to more
easily be able to comply with "CE" standards, where we are using a design system
based on a set of internationally recognized system of "component footprints" which
is already "IEC" approved.
Another issue that may not be getting enough "press" here, is that while 782 was a
requirement that was pretty much limited to the pcb design and manufacturing
industry (board and assembly houses), 7351 is reaching out farther in insustry, and
as I understand it, being accepted by the component manufactures themselves, which
will among other things, probably eliminate a lot of those screwed up component
outline drawings and bizarre footprints, where dimensions seem to be picked out of
the clear blue sky, that we have all had to deal with at one time or another, even
from otherwise reputable companies.
It additionally appears that 7351 has reached out to resolve most, if not all, of
the issues that prevented people from accepting 782 in the past, and please remember
that this is just the first cut of 7351.
I think that given the a little time for people to accept it, that 7351 will really
be a great step forward.
JaMi Smith
D 275? I still have a couple of copies of MIL-STD-275C (and possibly even a B)
kicking around here somewhere, which actually get looked at and used every now and
then.
----- Original Message -----
From: "Nick Ban (PCBL)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, July 29, 2005 9:22 PM
Subject: Re: [DC] IPC-SM-782 VS IPC-7351
> 1). Have the IPC-7351 specs replaced the IPC-SM-782 specs?
> The 782 is obsolete. The new standard is flying off the shelves @IPC from
> what I hear; many companies started adopting the new standard because the
> old standard was created a long time ago when cell phones were the size of
> bricks. Sounds trite, but technology changes.
>
> 2). Which spec should we be designing to?
> The industry dictates that, really. A growing number of companies are
> starting to use the new 7351, especially since it allows greater flexibility
> than the 782 (has three tiers), and comes available with a growing amount of
> free library documentation for thousands of parts. Does this mean you can't
> design to the 782? No, I'm sure there are still people who still use
> obsolete 'standards' like the D-275 (was replaced in 1998 by the far more
> comprehensive IPC-2220 Series).
>
> 3). Why have the specs changed?
> See answer #1 above.
>
> 4). Are the IPC-7351 Specs incorrect?
> The industry decides what is correct and what isn't. As Matthew said, if you
> still use the 782, your work is not necessarily wrong, but in choosing so,
> you are however limiting the amount of resources you can use to make your
> design sooo much more efficient. The earlier companies adopt the new
> standard, the more they benefit from first mover advantage because its not a
> question of whether or not the 7351 will completely replace the 782 in the
> industry. It's a questions of when (ie it will happen). Some lead, others
> follow, some try to do both. Neither is wrong, it depends on your business
> model.
>
>
> Nick
>
>
>
> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Matthew
> Lamkin
> Sent: Friday, July 29, 2005 8:32 AM
> To: [log in to unmask]
> Subject: Re: [DC] IPC-SM-782 VS IPC-7351
>
> And does this necessarily make any board that has been designed to the
> IPC-SM-782A specs wrong/old technology/bad etc?
>
> Most likely not, but I'm sure that Nick will be able to answer your
> question.
>
> Matthew Lamkin.
> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of Rich
> Schutz
> Sent: Friday, July 29, 2005 2:28 PM
> To: [log in to unmask]
> Subject: [DC] IPC-SM-782 VS IPC-7351
>
>
> We have been using IPC-SM-782 specs for years and have no problems. We
> request that are customers use the IPC-SM-782 specs when designing there
> PCBS. Some questions have come up in regards to the IPC-7351 specs, which
> some of our customers are using for there designs. We typically review the
> chip components on all of the boards we manufacture, in doing so I came
> across an issue where the chip components specs have changed between the
> IPC-782 and IPC-7351. My questions are:
>
> 1). Have the IPC-7351 specs replaced the IPC-SM-782 specs?
>
> 2). Which spec should we be designing to?
>
> 3). Why have the specs changed?
>
> 4). Are the IPC-7351 Specs incorrect?
>
>
> Rich Schutz
> CAD Engineer
> Phone: 440-358-5217
> Fax: 440-358-5201
> Apsco, Inc
> 3700 Lane Road
> Perry, Ohio 44081
>
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