Reliability

Index

EFR (Early Failure Rate)

EFR is an estimate (in ppm) of the number of early failures related to the number of devices used. Early failures are normally those which occur within the first 300 to 1000 h. Essentially, this period of time covers the guarantee period of the finished unit. Low EFR values are therefore very important to the device user. The early life failure rate is heavily influenced by complexity. Consequently, ‘designing-in’ of better quality during the development and design phase, as well as optimized process control during manufacturing, significantly reduces the EFR value. Normally, the early failure rate should not be significantly higher than the random failure rate. EFR is given in ppm (parts per million).

LFR (Long-term Failure Rate)

LFR shows the failure rate during the operational period of the devices. This period is of particular interest to the manufacturer of the final product. Based on the LFR value, estimations concerning long-term failure rate, reliability and a device’s or module’s usage life may be derived. The usage life time is normally the period of constant failure rate.

AOQ (Average Outgoing Quality)

All outgoing products are sampled after 100 % testing. This is known as AOQ. The results of this inspection are recorded in ppm (parts per million) using the method defined in JEDEC 16.

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Reliability