COMe-bSL6 – User Guide Rev. 1.4
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2.8.
MTBF
The following MTBF (Mean Time Before Failure) values were calculated using a combination of manufacturer’s test
data, if the data was available, and the Telcordia (Bellcore) issue 2 calculation for the remaining parts.
The Telcordia calculation used is “Method 1 Case 3” in a ground benign, controlled environment (GB,GC). This
particular method takes into account varying temperature and stress data and the system is assumed to have not
been burned in.
Figure 2 below shows MTBF de-rating for the E1 temperature range in an office or telecommunications environment.
Other environmental stresses (such as extreme altitude, vibration, salt-water exposure) lower MTBF values.
System MTBF (hours) = 467598 @ 40°C (Reliability report article number 36030-0000-28-8)
Table 22: MTBF Temperature de-Rating
The above estimates assume no fan, but a passive heat sinking arrangement. Estimated RTC
battery life (as opposed to battery failures) is not accounted for in the above figure and
needs to be considered separately. Battery life depends on both temperature and operating
conditions. When the Kontron unit has external power, the only battery drain is from leakage
paths.
