Acceleration tests, which are included in periodic reliability tests, are performed for a time equivalent to the product life, to judge the endurance of the product.
Voltage acceleration and temperature acceleration are included in the acceleration tests. ABLIC adopts temperature acceleration tests based on the Arrhenius model.
The acceleration factor conforms to JEITA standard EIAJ ED-4701 and is calculated by the following formula.
(Acceleration factor calculation formula) L = exp(Ea/kT2)/exp(Ea/kT1)
L: Acceleration factor
Ea: Energy of activation
k: Boltzmann coefficient
T2: Actual use temperature (absolute temperature)
T1: Acceleration test temperature (absolute temperature)
Specifically, the following conditions are substituted.
Energy of activation 0.5 eV
Boltzmann coefficient 8.617 × 10-5 eV/K
Actual use temperature 40°C
As a result of the above substitution, the acceleration factor at 125°C is shown to be 52 times that at 40°C. In sum,
1,000 hours are equivalent to 5.9 years
2,000 hours are equivalent to 11.8 years.
As shown above, successfully performing reliability tests at 125°C for 2,000 hours assures that the product life is judged to be at least 10 years at the actual use temperature.