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FIT rate for "TPS57114QRTERQ1"

Yonatan Guedj
Prodigy 10 points
Other Parts Discussed in Thread: TPS57114C-Q1

Regarding TI's "TPS57114QRTERQ1"

On TI website MTBF/FIT estimator we get FIT rate of 0.1

But on the Technical documentation section of this PN we get FIT rate of 11!

Can some one please explain this significant difference?

  • 0
    TI__Genius 14876 points

    Hello user,

    I will take care of your question.

    Let me come back to you by mid of this week.

    Thanks a lot!

    Regards,
    Dorian

  • +1 in reply to Dorian Brillet de Cande
    TI__Genius 14876 points

    Hello user,

    First of all  both FIT rates are correct. However, the two FIT rates are not the same and should not be confused as they are calculated on two fundamentally different methods.

     

    • TI website MTBF/FIT estimator

    This data (0.1 FIT for TPS57114QRTERQ1)  that you find on TI’s reliability estimator is the classical MTBF calculation based on the real TI reliability testing of real samples (HTOL, ELFR, etc.) normalized to a duration of 1000 h at a test temperature of 125°C (for details see the explanation on the link). Currently the device data, based on a sample size of 166651  tested for 1000 hrs and zero fails, gives a FIT rate of 0.1 . The FIT rate is very low due to the high sample size and high device hours for this mature  technology.

     

    • FIT Rate in the technical documentation (used for safety assessments according to safety standard ISO 26262)
      From the excerpt provided the data with 11 FIT for the same device  is coming from document  SLVAEP3A “TPS57114C-Q1 Functional Safety FIT Rate, FMD and Pin FMA”.  
      This “safety FIT rate” is not done on real testing. It is calculated based on the requirements of the IEC-standard  IEC TR 62380 / ISO 26262 part 11. It is a  calculated value based on the  quantity of components (different types pf transistors, diodes, capacitors etc.) used on the device with the assumption of a defined (worst case) failure rate by component type. This gives usually a much higher FIT rate compared to the results from the reliability testing described above.

     

    Note that the TPS57114QRTERQ1 is EOL and should not be used anymore in new application. The replacement part is  TPS57114CQRTERQ1 the same device (drop-in replacement with same data sheet parameters)  but with improved quality. The only difference between the two part numbers is the added polyimide layer providing a much improved robustness and quality performance.

    Let me know if you have any further questions or comments.

    Thanks a lot!

    Regards,
    Dorian

  • 0 in reply to Dorian Brillet de Cande
    TI__Genius 14876 points

    Hello user,

    Do you have any further questions here ?

    Let me know.


    Thanks a lot!

    Regards,
    Dorian

  • 0 in reply to Dorian Brillet de Cande
    TI__Genius 14876 points

    Hello user,

    Due to inactivity, I will close this thread.

    If you have any further questions or want to re-open the thread, please reply blow.

    Thanks a lot!

    Regards,

    Dorian