Generally, a test canbe accelerated if, for example, temperature, voltage, or the rates of
change are increased.
Different acceleration models are used, depending on the focus of the test i.e. which
failure mechanism is to be examined
. Common to all is that the
operating test point (indexed as "stress") is set higher than the target operating point in
the later application (indexed as "op"). The tests are performed on a selected number of
components in order to validate the electrical, mechanical and thermal parameters as
specified in the datasheet. Furthermore, these type tests also serve to determine the
test limits of routine tests in the current production.
RH )T(AF )T,RH(AF
For the type test, it is important to know for how long a test run needs to be operated to
obtain a statement about the usability of the device in the desired target application. In
other words: How many test cycles are necessary to reflect the expected real load
cycles in theapplicationwith sufficient reliability?
To answer this question, it is necessary to understand and analyse the target
application. A number of parameters are required according to
Usually the input parameter "load profile" turns out to be the biggest obstacle and has to
be partially replaced by estimates and/or experience. If all relevant input parameters are
available, the failure can be calculated/simulated for the time of one load cycle and the
loss profile thus is obtained.
Named after the Swedish physicist and chemist Svante August Arrhenius (1859 - 1927) who derived the
equation for the reaction kinetics in 1889. The Arrhenius factor
is related, amongst others, to the activation
energy being part of the test.
RH: Relativehumidity, n: Factor depends on the failuremechanism to be investigated.
c: Fatigue ductility. The ductility is amaterial property to deform plasticallywhen overloaded.