Hi Bill - take a look at the May 2000 issue of SMT magazine, "Designing
with CBGAs: An Experimental Approach" authored by Richard Morgen. The
article may be helpful for your application. Can you use a plastic BGA
instead of a ceramic BGA? The PBGAs have an overall longer thermal cycle
life than the CBGAs in most applications. Good Luck.

Dave Hillman
Rockwell Collins
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Bill Robinson <[log in to unmask]>@IPC.ORG> on 06/01/2000 08:18:27 AM

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Subject:  [TN] BGA application


Good Morning,

I have an application that requires using a 474 ball and a 250 ball
CBGA in a military environment.  These will be mounted on a random
kevlar Polyimide board, soft bonded to an aluminum thermal core.  Has
anyone had similar experience, and what have you learned?  Also will I
need to underfill the parts?  If so, what would you recommend for an
underfill material?  Thanks in advance for any help.

Bill

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