Technical Reference
65
2.7 Reliability
The Mean Time Between Failures (MTBF) prediction is calculated using a parts count
method. The calculation is based on the Telcordia SR-332, Method I Case 1 50%
electrical stress, 55 ºC ambient. The MTBF prediction is used to estimate repair rates
and spare parts requirements. The MTBF data is calculated from predicted data at
55 ºC. The MTBF for the board is 134,526 hours.
2.8 Environmental
Table 30 lists the environmental specifications for the board.
Table 30. Environmental Specifications
Parameter Specification
Temperature
Non-Operating
-20 °C to +70 °C
Operating
0 °C to +55 °C
Shock
Unpackaged 50 g trapezoidal waveform
Velocity change of 170 inches/second²
Packaged Half sine 2 millisecond
Product Weight (pounds) Free Fall (inches) Velocity Change (inches/sec²)
<20 36 167
21-40 30 152
41-80 24 136
81-100 18 118
Vibration
Unpackaged 5 Hz to 20 Hz: 0.01 g² Hz sloping up to 0.02 g² Hz
20 Hz to 500 Hz: 0.02 g² Hz (flat)
Packaged 5 Hz to 40 Hz: 0.015 g² Hz (flat)
40 Hz to 500 Hz: 0.015 g² Hz sloping down to 0.00015 g² Hz
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