SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: Rushabh
Subject: Capacitor failure rate for specialized scenario
The parameters you have chosen for environment and usage have negated the affects of temperature cycling, vibration, power on/off cycling, and component stress from the analysis for the capacitors in question. Therefore, the operational, cycling and solder joint portions of the capacitor failure rate are zero for the capacitor in your operational and non-operational scenarios (please review the PRISM failure rate tab for each component). The only factors that remain are the non-operational and EOS/ESD failure rate contributions. For capacitors, the EOS/ESD failure rate is a constant that does not change based on operation/environment. The failure rate due to non-operation is zero for a capacitor that is operating at a 100% duty cycle while there is a non-operational failure rate for a capacitor that is in a non-operating scenario. As a result we now have a capacitor with a predicted non-op failure rate that is higher than what is predicted in the operational scenario.
You have identified a specific set of parameters that negate the operational portion of the capacitor failure rate. This issue needs further analysis and will require update to the capacitor model in a future PRISM version. In the meantime, I recommend that you use the PRISM default parameters for stress and capacitance when performing an analysis based on your operational conditions.
If you have any additional questions, feel free to contact me.