Rpredict's MIL-HDBK-217F3

• MIL-HDBK-21F3 has never been release, but how to upgrade MIL-HDBK-217F2 to the level of year 2003?

 

Comparing Reliability Predictions to Field Data for Plastic Parts in a Military, Airborne Environment Presented during the RAMS Conference 2003 in Tampa USA Author: Laura M. Brown • Northrop Grumman Electronic Systems • Baltimore This paper examines two popular prediction methods and compares the results to field data collected on Plastic Encapsulated Microcircuits (PEMs) operating in a military, airborne environment. The comparison studies focused on three digital Circuit Card Assemblies (CCAs) designed primarily with plastic, surface mount parts. Predictions were completed using MIL-HDBK­217 models and PRISM®, the latest software tool developed by the Reliability Analysis Center (RAC). MIL-HDBK-217F2. The MIL-HDBK-217 predictions which correlated best to the field data were based on quality levels pQ of 2 and 3, rather than the typical pQ values of 5 or higher, traditionally assigned per the handbook's screening classifications for commercial, plastic parts. Since the quality factor is a direct multiplier in the prediction models, the impact of changing pQ was significant. The predictions with modified pQ factors of 2 or 3 were within 10% of the demonstrated field reliability for the three Circuit Card Assemblies in the study. PRISM®. The initial findings from the PRISM® tool revealed the predictions were optimistic in comparison to the observed field performance, meaning the predictions yielded higher Mean Time To Failure (MTTF) values than demonstrated. Further evaluation of the PRISM® models showed how modifying default values could improve the prediction accuracy. The impact of the System Level Multiplier was also determined to be a major contributor to the difference between PRISM® predictions and field data. Finally, experience data proved valuable in refining the prediction results. The findings from this study provide justification to modify specific modeling factors to improve the predictions for PEMs, and also serve as a baseline to evaluate future alternative prediction methods. REFERENCES 1. Military Handbook 217FN2, Reliability Prediction of Electronic Equipment, Department of Defense, 1995. 2. PRISM® Software, Users Manual Version 1.0, Reliability Analysis Center, 2000. 3. A. Bumbalough, Electronics Parts Obsolescence Initiative Workshop, 4 & 5 April, 2000, Baltimore, Maryland. 4. National Semiconductor Corp., Plastic Packages, August, 1999. Internet (e-mail): LMBrown@northropgrumman.com

Microcircuit Reliability Prediction Source:www.crane.navy.mil/sd18/MicrocircuitReliability.htm The Reliability Prediction of Electronic Equipment Handbook, MIL-HDBK-217F notice 2, is used as a guideline to establish and maintain probability for microcircuits. An area of some current disagreement in the MIL-HDBK-217F notice 2 is with the Quality Factor for commercial/consumer microcircuits. The handbook lists the Quality Factor (pQ) as 10. This was established prior to 1991. Through review with industry, the Quality Factor for consumer plastic encapsulated microcircuits (PEMs) used in NAVSEA systems, is being reduced to a Quality Factor (pQ) of 4.0. In addition, for PEMs used in NAVSEA systems, the Environmental Factor in the MIL-HDBK-217F notice 2 should be modified to the following: a. For microcircuits used in the Protected Environment, the Environmental Factor (pE) is 0.5. b. For microcircuits used in the Normal Environment, the Environmental Factor (pE) is 5.0. In addition to the MIL-HDBK-217F, notice 2 there are other methods used to predict microcircuit reliability. The MIL-HDBK-217F, notice 2 is the preferred method until a suitable replacement is developed. Protected Environment The protected environment is applicable for parts employed according to the following provisions: a. used in readily accessible maintenance applications b. used in a controlled environment c. with a temperature range of 0°C to 70°C d. not used in an application with shock, vibration, pressure or moisture e. not stored for later usage f. with an application life-span of up to 5 years Normal Environment The normal environment is applicable for parts employed according to the following provisions: a. used in inhabited applications b. used in applications usually accessible for maintenance or replacement c. used in an uncontrolled, but not extreme, temperature environment with a temperature range of -40°C to +85°C d. used in an application having a minimal to low-medium controlled shock, vibration, pressure or moisture environment e. can be stored for later usage (not to exceed 10 years) f. with an application life span of 5 to 10 years Severe Environment The severe environment is applicable for parts employed according to the following provisions: a. used in uninhabited environments b. used at varying temperatures or temperature extremes c. with a temperature range of -55°C to 125°C d. used in an application having a medium to high shock, pressure, vibration, or moisture environment e. can be stored for later usage (over 10 years) f. with an application life span of 10 to 20 years