### 11/15/2006 Assessed Failure Rate on ECX-31B

```11/15/2006
Assessed Failure Rate on ECX-31B
1.
Assessed Failure Rate
Assessed Failure Rate of ECS-.327-12.5-34B; 21.9 (Fit) Confidence Level at 60%
Temperature at 25°C
2.
Calculation Method
(1) Results of Live Test at +85°C
Model
ECX-31B
Sample Size
300
Testing Time
2,000 H
(2) Assessed Failure Rate with Life Test at +85°C
Failure Rate
Total Testing Time
600,000 H
Number of Failures
0 pc.
Confidence Level at 60%
λ=r/T
Where r: Number of Failures
T:Total Testing Time
We presume with the upper failure rate because the number of failures is 0.
λu=0.917/T
=0.917/600,000
=1,528 (Fit)
Confidence Level at 60%, r=0
Note: This formula can be found in JIS C5003-1974: General Test Pocedure of Failure Rate for
Electronic Components.
(3) Assesed Failure Rate at +25°C
The Temperature Acceleration Factor is given by Arrehenius Law.
Acceleration Factor
αt=e
(∆/k)*(1/T0-1/T1) = 69.6
Where: Activation Energy:
∆E=0.65 (eV)
Boltzmann Constant: k=8.6173x10-5 (eV/K)
Reference Temperature: To=25°C=298(K)
Temp at Acceleration Condition: T1=85°C=358(K)
Conclusion Assessed Failure Rate at 25°C
λu=1,52/8(Fit)/69.6
=21.9(Fit)
1 1 0 5
E C S , I n c . I n t e r n a t i o n a l
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