> 
> 
> 122 page Agilent pdf giving footprints for about every smt 
> semiconductor component you can imagine. Disappointingly limited on 
> dimensions, but usefully provides basic dimensional data in one 
> document
> 
        http://eesof.tm.agilent.com/docs/adsdoc2003A/pdf/layout.pdf

You might try over at www.smta.org but I have doubts about "free"
anything from them.  One very comprehensive book is "IPC-SM-782A" but
the IPC gives nothing away.  Last time I purchased the book was in 2001
and it was nearly $100 then.  But it did have just about everything you
needed for creating land patterns for SMT as well as general guidelines
for placement spacing, edge clearances, etc.  I don't believe it has BGA
however.  Also, it may not have been updated in the last few years, IPC
seems a little slow in that respect.

Rob
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