John McGee wrote:
> 
> Hello Technetters-
> 
> I'm totally unfamiliar with BGA technology.   Is there a specification for
> ball
> coplanarity?  How is it specified and what would be typical numbers for
> contacts
> of about 1mm diameter over a seating plane with an area of about 325 sq. mm,
> about 18 x 18mm (if that's pertinent)?

	If I understood a comment at today's IPC/SMTA BGA Symposium,
	there is a specification of +/-.1mm, or a range of ~8 mils.
	I think this was quoted from Jedec 95, which I can't put my
	hands on right now to confirm.
-- 
 
      Jeff Seeger                             Applied CAD Knowledge Inc
      Chief Technical Officer                      Tyngsboro, MA  01879
      jseeger "at" appliedcad "dot" com                    508 649 9800

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