Technetters,

We are faced with a design that puts 2 BGAs on the solder side of a 
board. It will therefore go through reflow on the bottom when building 
the other side. The BGA is 19 x 19 mm 484 balls .8mm pitch. Av Weight 
1.3302 g.  This is a lead free design. I seem to have seen a paper on 
the subject discussed on technet, but the archives do not work for me 
right now.

We have done thousands of boards with BGAs on both sides, but always 
small ones with max ball count at 84. We have never one this size. Any 
experiences out there that you can share? Do's and don'ts?  I can tack 
the corners of the  BGA with SMT adhesive, but I would rather not if I 
can avoid it.

-- 
Leif Erik Laerum




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