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SN751177: DPPM/FIT/MTBF estimator & Temperature Change FIT

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Replies: 4

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Part Number: SN751177

Hi,

 

Could you please check below?

 

In Temperature Change FIT,

Q1. What is Application Temperature?

Q2. What is Qualification Temperature?

Q3. How we can use FIT at Activation Energy, 0.3 eV, 0.7eV and 1.0eV? It would be helpful to give me some examples.

 

In DPPM/FIT/MTBF estimator,

Q4. MTBF / FIT shows MTBF=1.44*10^9、FIT=0.7. Are these value at 55C temperature?

 

If the question for Temperature Change FIT is not in this thread, please let me know where I should ask these questions.

 

 

Best regards,

Hide

 

  • Hello Hide-san,

    The application temperature is the ambient operating temperature used in the end application.  The qualification temperature is the temperature at which the stress test is performed.  This is found on the DPPM/FIT/MTBF estimator table (see below value of 125 C):

    The activation energies can vary depending on the process technology used and the type of defects targeted for the FIT/DPPM estimate.  (For example, a given process technology an oxide defect may have an activation energy of 0.3 - 0.5 eV while electromigration of a contact/via may have an activation energy of 0.9 eV.)

    You are correct that the data provided in the DPPM/FIT/MTBF estimator table assumes an ambient temperature of 55 C.

    For further reference, you may find this app note on calculating FIT useful: .

    If you have any further questions please let me know.

    Regards,
    Max Robertson

  • In reply to Max Robertson:

    Hi Max,

    Thank you for your response. Could you please check the question below additionally?

    In application note (SPRABY3) you attached, I would like to know the relation between DPPM and MTBF(FIT).

    Formula (1) & (2) in application note (SPRABY3), how DPPM relate to FIT value? In this Formula, "f = number of failures" means DPPM?

    Best Regards,

    Hide

  • In reply to Hideyuki Takisawa:

    Max,

     

    In addition, in Temperature change FIT, if the following parameters put the each item, FIT is calculated, my understanding correct?

    The result of MTTF at 0.7 eV was 1.43e+9 compare with 1.44 e+9 by DPPM/FIT/MTBF estimator. Is the difference from simulation accuracy?

     

     ・Application Temperature   = +55℃

     ・Qualification Temperature = +125℃

     ・DPPM = 56

     

    Best regards,

    Hide

     

  • In reply to Hideyuki Takisawa:

    Hello Hide-san,

    You can find the definitions for FIT and DPPM and how they relate to one another on this page:

    www.ti.com/.../reliability-terminology.html

    (It explains it better than I can, although if you have any questions on it please let me know.)

    You are correct about the usage of the "Temperature change FIT" website. The differences between the result you see on it and the DPPM/FIT/MTBF estimator table should be due to rounding differences. In both cases the MTBF should be calculated as 1E9 / FIT.

    Best regards,
    Max