Understanding the performance of a component over time can help to estimate your device’s operational lifetime. Changes in applied voltage and temperature will have an effect on an individual component’s lifetime. As a baseline, KEMET provides data that can be used with the MIL-HDBK-217[sre.org] formula to calculate Failures In Time (FIT) for ceramic and tantalum capacitors. Measuring the number of failures over time provides a failure rate (λ). The failure rate that occurs during one billion device hours is called the Failure In Time (FIT). In other words,

The Mean Time Between Failure (MTBF), or for components, the Mean Time To Failure (MTTF) is the distribution for a population of parts. MTTF can be determined by taking the reciprocal of FIT (λ).

### Failure In Time (FIT) Example

This application note walks through an example of calculating FIT for a capacitor. The example uses a KEMET ceramic capacitor and the KEMET FIT Calculator tool.

Related: KEMET FIT Manual