2410-41, 2410-42 and 2410-43 FEP Maintenance & Support Guide
7-1
Revision 1.0, May 2006
CHAPTER 7
RELIABILITY PREDICTIONS
7.1
METHODOLOGY
Reliability predictions were completed using the Bellcore 5 reliability standard developed by AT&T
Bell Laboratories. Component failure rates are calculated based on technology, stress levels, gate or
transistor density (ICs), package style, and quality level. Failure rates provided by the component
manufacturer have been used in some cases, where available. Failure rates are expressed in FITs, which
is failures per billion hours. Mean Time Between Failures (MTBF) is the inverse of the failure rate and
is the average time between failures.
7.2
ASSUMPTIONS
•
Ambient input air temperature does not exceed 30 deg. C.
•
Ground, Fixed, Controlled Environment
•
Components are Quality Level I.
•
Component stress levels do not exceed rated limits (i.e. power dissipation, junction temperature,
etc.). In other words, components are used within specification limits. The parts count prediction
assumes parts are used at a maximum of 50% of rated electrical stress.
•
Component failure could result in FEP failure (except for the power supplies that are configured in
parallel redundancy). However, Bellcore’s architecture uses FEPs in parallel redundancy.
