For Consumer / IoT
Product reliability is indicated by Mean Time Between Failure (MTBF) for repairable, Mean Time To Failure (MTTF) for unrepairable, and Failures in Time (FITs). MTTF is applied for semiconductor devices because they are unrepairable.
MTTF and failure rates of Ricoh electronic products are suggested in the PDF below.
FIT is calculated by the following formula:
1FIT = 10-9 (Failure/Time) = 10-4 (%/1000h)
The data is obtained from test results with 110 samples and zero defects.
This is calculated as follows:
FIT value = (number of defects) / (number of tests × test time × acceleration factor)
As the number of tests increases, the FIT value decreases.
In Ricoh electronic devices, data is calculated with 110 pieces, due to the cost and man-hours required for the test.