Dave Sharples wrote:
>
> If this is so how do you fanout fine pitch BGA components or even 35 mil
> pads on 50 mil pitch.

Remember, the IPC rules are guidelines only. I understand that most of
the people on those committee's were also assembly people more than
designers, & hence understandable why the rules might lean heavily that
way.

If you want your design bullet-proof, follow the guidelines (& hence
don't use BGAs - yeah right!). Reality then sets in & you then elect to
break the rules advisedly only where you really need to (i.e. around the
BGA). If you were really wary, you could break out the outer two rows of
the BGA by the IPC recommended hole-pad clearance to further reduce the
minimal risk but, speaking as a designer, I would prefer not to do that
(takes up *lots* of area etc).


--
Dom Bragge   CID        "The pink building"
Production Manager      Level 1, IBC Bldg
KLAXON IQA              Australian Technology Park
bh+61-2-9209-4404       Eveleigh 1430 NSW
fx+61-2-8374-5030       (Sydney, AUSTRALIA)
www.klaxoniqa.com

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