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| >From willli Wed Jul 9 17: |
05:04 1997 |
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Wed, 09 Jul 1997 18:15:20 -0400 |
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| From [log in to unmask] Thu Jul 10 08: |
44:55 1997 |
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by ipc.org (Smail3.1.28.1 #2)
id m0wm4r0-000BjaC; Wed, 9 Jul 97 17:04 CDT |
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Applied CAD Knowledge Inc |
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Haalllooo, Technet!
I'm (probably not alone in) facing pressures to setup non-
symmetrical stackups, to accomodate the growing number of
mixed 5v and 3.3v boards.
I fully understand the unkind things that can happen when
we're not distributing the negative layers well, but "how
bad is bad?" In the ~8x8" .062 world, is flexibility vis
non-functional-copper (add/remove) enough to be reasonably
certain of flat product?
Would adding extra relief pads on the offending plane layer
be beneficial? How about a positive-image mesh?
Does this become more critical with increasing overall size,
as I'd expect?
Am I correct to worry about this, considering 1000s as a
product life?
Thanks in advance,
--
Jeff Seeger Applied CAD Knowledge Inc
Chief Technical Officer Tyngsboro, MA 01879
jseeger "at" appliedcad "dot" com 508 649 9800
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