The reliability of electronics is influenced not only by design, but also by the parts, components and materials used in their manufacturing. Also the manufacturing processes and the various stresses the products will undergo during their entire lifetime have an influence on reliability.
It is, therefore, important to determine or be familiar with the factors relating to the technology used for the product, and the conditions under which the product will be used. The most important phases after a product's manufacture are storage, transportation, installation and actual operation and maintenance.
Reliability tests simulate use conditions and stresses
- Temperature and temperature variations
- Humidity and humidity fluctuation (possible condensation)
- Mechanical stresses - vibration and shock
- Electrical stresses - electrical overstress (EOS), electrostatic discharges (ESD)
A life test simulates the conditions during the product's lifetime, seeking to take all cumulative stresses from operation and environmental conditions into account. Conditions that are more stressful than the actual operating conditions of the device must be used in the test time.
The accelerating effect of the tests can be estimated through acceleration models.
Testing for reliability and service life in a nutshell
- The technology, structures, components and materials along with their mechanisms are determined
- Operating conditions during the different phases of the product's lifetime are determined
- A test or combination of tests that will ensure conformity to reliability requirements is designed
- The tests, including initial, interim and final measurements, are carried out
- The failures that occur during testing are analyzed
- Based on the results, conclusions on the product's failure mechanisms and reliability parameters (e.g. failure rate, lifetime) are calculated and presented