PRISM Forum - Message Replies


Topic: PRISM Questions and Answers
Topic Posted by: SRC (src_forum@alionscience.com )
Organization: SRC
Date Posted: Wed Jan 12 8:33:33 US/Eastern 2000
Topic Description: Welcome to the PRISM forum! Please feel free to post your questions and comments about the PRISM assessment software here.

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Original Message:

Posted by: Fred Levesque
Organization:Raytheon
Date posted: Fri Apr 28 13:28:19 US/Eastern 2000
Subject: Solder-joint factor
Message:
In performing RACRate calculations, I have noticed that for most parts the "Solder Joint" factor is the largest contributor to the failure rate. In IC memories this factor is two orders of magnitude larger than everything else combined! What is the justification for this effect?


Reply:

Subject: Solder Joint Factor
Reply Posted by: Norman B. Fuqua
Organization: RAC
Date Posted: Fri Apr 28 15:04:56 US/Eastern 2000
Message:
In answer to your question I would first ask three questions. What type of part are you looking at, what operating environment are you using and finally what operating profile are you using? The "Solder Joint" contribution is a function of the specific RACRates model used. It will be different for each part type. The specific contribution then is driven primarily by the operating environment (i.e., the difference between the Operating ambient temperature plus the internal temperature rise within the part and the Dormant Temperature) and the operational profile (i.e., the number of temperature cycles experienced).


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