SRC Forum - Message Replies


Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

Back to message list Show all replies Topics List About this forum
Original Message:

Posted by: Tom Clark (tclark@sanera.net )
Date posted: Thu Jul 11 14:51:47 US/Eastern 2002
Subject: Backplane Reliability Models?
Message:
I would like to know standard techniques used to model the reliability of a backplane. Since a backplane is not easily replaced, the MTTR is high. This means the FIT rate must be extremely low in order to show a reliable system may be built with that backplane. However, using the SR-332 standard 0.2 FITs per pin, a backplane with many high density connectors can quickly accrue FITs. The connectors I am using are rated for 200 matings. It seems unlikely that they will encounter more than 20 matings in the life/mission of the product. Can I use this information to change how I model the backplane? From looking at data shared by other companies, there is clearly a standard way to derate the FITs to show the backplane is ultra reliable (as it should be).....


Reply:

Subject: Connector Pin Failure Rate
Reply Posted by: B. W. Dudley (bdudley@alionscience.com )
Organization: RAC
Date Posted: Thu Jul 25 13:44:35 US/Eastern 2002
Message:
The failure rate for connector pins in the Telcordia SR 332 model is based on their field experience failure data and is modified only by a temperature factor. It is not stated if this base failure rate is at the maximum mating and un-mating rate or some derated value. The best source for this information is the developer of the model. Arbitrarily, modifying the model without understanding the parameters that were used is risk that cannot be defined. Incidentally, connectors and connections are components that have a high number of defects and are subject to mishandling causing failures


Reply to this message