Bob,

     We have found that we have to plug (not just tent) the vias under
     BGA parts so that there aren't solder shorts from a via to a BGA
     pin under the part.  This is an additional process for the PCB
     fabricator, I can't tell you how much the additional cost is.

     Also consider that special equipment will be required to inspect
     and rework BGA parts on the final assembly.

     Jon


______________________________ Reply Separator _________________________________
Subject: [DC] BGA vs PQFP
Author:  "DesignerCouncil E-Mail Forum." <[log in to unmask]>,
[log in to unmask] at Internet
Date:    4/17/98 2:40 PM


Can anyone give me some ball-park numbers (either in percent or dollars)
on the increased cost associated with a printed circuit board that has
been designed with the use of a  BGA packaged IC instead of a PQFP
packaged IC? We are working on a new design that could use either a
352-pin BGA, 1.27mm pitch IC or two 160-pin PQFP, 0.5mm pitch IC's. If I
could get any info on the increased costs associated with fabricating the
bare board and/or the assembly/testing of the final assembly, it would be
a great help in deciding what path to take.

Thanx for any help that can be given.

Bob Walker
Sr PCB Designer

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