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January 1997

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Wed, 15 Jan 1997 13:49:42 -0500 (EST)
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In a message dated 97-01-14 12:56:25 EST, you write:
<< 
 I would like to know if anyone has any reliability information on the 
 TSOP and PLCC at 120 degrees F., to 150 degrees F, during the life of the
 assembled board.    
 Michael Cussen  
 [log in to unmask]  
 1-810-477-3900-3306>>
Michael,
To my knowledge, there is no test or field assembly reliability data
available in the range 48C to 66C. If there is, I'd be interested in seeing
it.
However, there is data for larger delta Ts (e.g., see reliability books by
Lau et al.) which you then need to extrapolate to your own conditions. PLCCs
have rather compliant leads so solder fatigue due to global CTE mismatch
(component to board) will be relatively small and you need a
model/acceleration factor that accounts for LOCAL CTE mismatch (between
solder, board and package lead). This is even more significant with Alloy 42
TSOPs (see TechNet archives for previous discussions on Alloy 42 TSOP solder
cracking).
Jean-Paul ________________________________________________________________
Jean-Paul Clech
EPSI Inc., P. O. Box 1522, Montclair, NJ 07042 - USA
tel: +1 (201)746-3796  fax: + 1 (201)655-0815
Home page: <A HREF="http://members.aol.com/Epsiinc1/index.html">http://members
.aol.com/Epsiinc1/index.html</A>
- click above, or copy: http://members.aol.com/Epsiinc1/index.html
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