Forum: Reliability & Maintainability Questions and Answers
Posted by: Chuah Chiew Peng
Organization:University of Sheffield
Date posted: Thu Jul 31 5:32:29 US/Eastern 2003
Subject: Electronics part reliability
I am doing a reliability assessment on a fault tolerant matrix converter that i am designing. Is it safe to assess the reliability of the system from the failure rate datas that i can from the manufacturer and the reliability data handbook from RAC? I am using negative exponential law for calculating the reliabilities of the system. Please advice.
Posted by: Chua Peck Seng
Date posted: Sun Jul 27 21:12:04 US/Eastern 2003
Subject: Junction Temperature
Based on thermal analysis, measurement and thermal resistance given by IC manufacturers, we've estimated in our developmental systems, some of the junction temperature of the commercial grade ICs have exceeded the maximum junction temperature of 150 degrees. We're thinking of changing these ICs to industrial grade. However, is there any difference in the junction temperature for commercial and industry grade ICs ?
Posted by: Beth
Date posted: Tue Jul 22 20:38:09 US/Eastern 2003
Subject: Comparing Reliability
Reliability of old system is .9958, new system is .9938. How do I calculate the reduction? I don't seem to be getting the same answer a previous report indicates, so... the report indicated 37 % decrease and I do not know where that came from nor do I know if its correct.
Posted by: Kevin Silke
Date posted: Tue Jul 22 20:06:48 US/Eastern 2003
Subject: Temperature Cycling
Is it appropriate to define a unit level non-operating temperature cycle test using JEDEC standard JESD22-A104? We're looking at test condition B (-55C to +125C) for 1000 cycles. Is this a component level standard? We want to define an appropriate unit level test to stress the interconnects of production hardware.
Posted by: Ela
Date posted: Tue Jul 22 11:54:50 US/Eastern 2003
Subject: Storing Environment defenition for ElecroOptical Equipment
Our problem is to define proper storing conditions (humidity and temperature)to Elctro-optic Equipment. According to field data the influence of temperature is minor in comparison to humidity , despite the theory of Ahrenius Model and MIL-HDBF-217. So we are considering to start storing this type of equipment without temperature control (just humidity conrol). We are concerned that this action will cause serious shortage of system life time? What can you advise in this case?