Datasheet

6© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard A4075_ALS70_71 • 7/15/2020
Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com
Screw Terminal Aluminum Electrolytic Capacitors – ALS70/71, High CV, +85°C
Shelf Life
The capacitance, ESR and impedance of a capacitor will not change signicantly after extended storage periods, however,
the leakage current will very slowly increase. KEMET products are particularly stable and allow a shelf life in excess of three
years at 40°C. See sectional specication under each product series for specic data.
Re-Age (Reforming) Procedure
Apply the rated voltage to the capacitor at room temperature for a period of one hour, or until the leakage current has fallen
to a steady value below the specied limit. During re-aging, a maximum charging current of twice the specied leakage
current or 5 mA (whichever is greater) is suggested.
Reliability
The reliability of a component can be dened as the probability that it will perform satisfactorily under a given set of
conditions for a given length of time.
In practice, it is impossible to predict with absolute certainty how any individual component will perform. Therefore, we
must utilize probability theory. It is also necessary to clearly dene the level of stress involved (e.g., operating voltage, ripple
current, temperature and time). Finally, the meaning of satisfactory performance must be dened by specifying a set of
conditions that determine the end of life of the component.
Reliability as a function of time, R(t), is normally expressed as: R(t)=e-
λt
, where R(t) is the probability that the component will
perform satisfactorily for time t, and λ is the failure rate.
Failure Rate
The failure rate is the number of components failing per unit time. The failure rate of most electronic components follows
the characteristic pattern:
• Early failures are removed during the manufacturing process.
• The operational life is characterized by a constant failure rate.
• The wear out period is characterized by a rapidly increasing failure rate.
The failures in time (FIT) are given with a 60% condence level for the various type codes. By convention, FIT is expressed
as 1 x 10
−9
failures per hour. Failure rate is also expressed as a percentage of failures per 1,000 hours, e.g., 100 FIT = 1 x 10
-7
failures per hour = 0.01%/1,000 hours.
End of Life Denition
Catastrophic Failure: short circuit, open circuit or safety vent operation.