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Tue, 21 Apr 1998 10:08:43 EDT |
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Hi Charles,
The possible problems with larger chip components are two-fold:
(1) Being ceramic these components have a large celta-CTE with FR-4 PCBs.
Thus, in temperature cyclic operational environments they may have inadequate
fatigue life. For a well designed assembly, these components typically are the
ones with the largest reliability threat in telecommunications outside plant
environment (or more severe).
(2) Large chip capacitor are more prone to cracking. This can be helped by
limiting the size of the solder fillet (or eliminating it alltogether), and
reducing the size of the attachment pads.
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask]
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