The lifespan of a device refers to the period during which it meets all performance indexes or acceptance requirements in the product specifications under the specified stress environment. Typically, the weakest part of a device determines its lifespan. When the device's failure rate conforms to Weibull distribution, the time when the cumulative failure rate of a device is below 63.2% is defined as the characteristic life of a device. We use the characteristic life curve (bathtub curve) to describe it, which consists of the following three parts:

The first part is the failure rate that decreases with time, which is called early failure.

The second part is the approximately fixed failure rate, which is called random failure.

The third part is the failure rate that increases with time after exceeding its design life, which is called wear out.

Anlogic Infotech introduces JESD85 (Methods for Calculating Failure Rates in Units of FITs) to standardize the measurement of product failure.

The calculation is described as follows:

Anlogic Infotech evaluates the reliability of devices running in different operating environments based on a set of generally acceptable stress test criteria that the devices can withstand to ensure good reliability performance in the application.