Template:Example:CD-GLL Weibull

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CD GLL-Weibull Example


A sample of 18 units of an electronic component was subjected to temperature and voltage stresses. The temperature was initially set 100K and was then continuously increased to 200K over a period of 20 hours. The temperature was again increased at 120 hours to 300K over a 20 hours period as shown in Fig. 3. The voltage was initially set 4V and was then increased continuously to 8V over a period of 10 hours. The voltage was again increased at 110 hours to 12V over a 10 hours period as shown in Fig. 4.

Temperature profile.


Voltage profile.


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The failure times, as entered in ALTA PRO, are shown in the next figure.

ALTA12.2.gif


The stresses are transformed using an Arrhenius life-stress relationship for temperature, a Power Law life-stress reliationship for voltage and the Weibull distribution as the underlying distribution.

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The estimated model parameters are shown next.


[math]\displaystyle{ \begin{align} & \widehat{\beta }= & 3.5073 \\ & \widehat{{{\alpha }_{0}}}= & -1.3773 \\ & \widehat{{{\alpha }_{1}}}= & 450.46 \\ & \widehat{{{\alpha }_{2}}}= & 1.98 \end{align} }[/math]


The use level (temperature = 100K, voltage = 4V) reliability plot is shown in the next figure.

Reliability plot at normal use conditions (100K and 4V).