Glossary comparison
DPPM vs FIT: what is the difference?
The difference
FIT counts failures per billion device hours of operation and describes reliability over time. DPPM counts defective parts per million shipped and is mainly about escapes from test.
Defective parts per million (or per billion, as TI tracks it) measures the share of shipped parts found defective, a quality measure. FIT is a rate of failures over operating time.
The two terms
DPPM
The count of defective units per million shipped, the standard currency of component quality performance. Automotive targets have tightened from around 10 DPPM to around 10 defective parts per billion, and the figure is tracked separately for field returns and incoming inspection.
FIT
The standard failure rate unit, one failure per billion device hours of operation. Rates from accelerated tests are converted to FIT at a stated use temperature, voltage and confidence level, and FIT values add across components in a system.
Side by side
| Field | DPPM | FIT |
|---|---|---|
| Stands for | Defective Parts Per Million | Failures In Time |
| Type | Metric | Acronym |
| Domain | Reliability & Quality | Reliability & Quality |
| Group | Quality systems | Reliability modelling |