T-NT Acceleration Factor

The acceleration factor for the T-NT relationship is given by:

$images\10_3_1.gif$

where,

ˇ $images\luse.gif$ is the life at use stress level,

ˇ $images\laccel.gif$ is the life at the accelerated stress level,

ˇ $images\vu.gif$ is the use temperature level,

ˇ $images\va2.gif$ is the accelerated temperature level,

and

ˇ $images\ua.gif$ is the accelerated non-thermal level,

ˇ $images\uu2.gif$ is the use non-thermal level.

The acceleration factor is plotted versus stress in the same manner used to create the life vs. stress plots. That is, one stress type is kept constant and the other is varied (see Figures 3 and 4 below).

$images\accfactemp.gif$

Fig. 3: Acceleration factor vs. temperature at a fixed voltage level.

$images\accfactvolt.gif$

Fig. 4: Acceleration factor vs. voltage at a fixed temperature level.