Mtbf (Mean Time Between Failures - Teknor Industrial Computers VIPer807 Technical Reference Manual

A.03 MTBF (MEAN TIME BETWEEN FAILURES)
The reliability analysis performed on the VIPer807 reflects all available options and has
resulted in the following predicted reliability:
TABLE A-3: Reliability Prediction
Standard
Configuration
Option 1: Basic board
Option 2: Basic board plus 2MB Flash memory
Option 3: Basic board plus 4MB Flash memory
The MTBF is estimated using the prediction data from MIL-HDBK-217F, Reliability
Prediction of Electronic Equipment (Dec. 1991).
The VIPer807 board is considered functioning in a Ground Fixed environment as defined
in MIL-HDBK-217F. The calculations are performed at 20°C with a temperature rise of
10°C which is due to heat dissipated by active components.
It is assumed that only one failure at a time can occur and that the failure of any
component will result in the system becoming inoperative or, as a minimum, resulting in
a degraded mode of operation requiring repair action. All components are considered as
having an exponential distribution of time to failure, with a constant failure rate. A failure
rate is attributed to each component called in the parts list, according to the stress levels it
is submitted during normal operation.
VIPer807 Specifications
CPU
Intel 486DX2-33 5V
Intel 486DX2-66 5V
Intel 486DX4-100 3.3V
AMD 486DX2-66 3.3V
AMD 486DX4-100 3.3V
AMD 5x86-133 3.3V
Intel 486DX2-33 5V
Intel 486DX2-66 5V
Intel 486DX4-100 3.3V
AMD 486DX2-66 3.3V
AMD 486DX4-100 3.3V
AMD 5x86-133 3.3V
Intel 486DX2-33 5V
Intel 486DX2-66 5V
Intel 486DX4-100 3.3V
AMD 486DX2-66 3.3V
AMD 486DX4-100 3.3V
AMD 5x86-133 3.3V
A-4
MTBF Failure Rate
-6
(Hours) (x10 )
134544 7.4325
120544 8.2957
131749 7.5902
152556 6.5550
143676 6.9601
129157 7.7425
131544 7.6020
118130 8.4652
128872 7.7597
148711 6.7245
140260 7.1296
126390 7.9120
130550 7.6599
117328 8.5231
127918 7.8175
147442 6.7823
139131 7.1875
125472 7.9699