MTBF and SIL information request

Hello Alfonso,

Please review the information on the  MTBF/FIT estimator page: https://www.ti.com/quality/docs/estimator.tsp . 

Another good resource is the Reliability page: https://www.ti.com/support-quality/reliability/reliability-terminology.html .

After review, please let us know if you have questions about specific part numbers in your design. 

Regards, 

~Leonard  

Hi Leonard, thank for you reference 

If I'm not mistaken in your tool too

https://www.ti.com/support-quality/reliability/temperature-change-FIT.html 

there is no trace of thermal stress dependence as reported in the paper I have already submitted (Reliability and power management of integrated systems" https://ieeexplore.ieee.org/document/1333252) to you and confirmed by the IEC62308 standard.

In particular paragraph 5.8 of IEC62380 refers parameters necessary to define the mission profile and states:

"For on/off working this daily variation is also applied on the equipment, however, only the greater temperature variation has to be taken into account,
because the highest one has the main effect on the reliability of the device packages and on the mounting process."

This corresponds to the physical principles underlying the paper we have already referred to you ("Reliability and power management of integrated systems" https://ieeexplore.ieee.org/document/1333252 ). 

From rumours that we have even the new standard 61709 will integrate principles of FIDES proposing again the correlation between MTBF and thermal cycling induced  by on/off working.

In offers, our customers may ask us to calculate reliability according to these standards.
To be able to claim that for your technologies we can not use them we would need to have either another normative reference or demonstration with experimental tests.

For example  can you state that your test https://www.ti.com/support-quality/reliability/reliability-testing.html demonstrate that reliability of your technologies are independent of the thermal cycling induced by any on/off operation at any frequency ?

Regards

Hello Alfonso,

This is a very interesting yet complex question.  We are familiar with the concerns regarding power cycling, and our Space-rated components take this into account.  I am trying to locate an expert on this subject in our Quality organization, and this may take several days.  

I'll get back to you by next week, May 10.   Thanks for your patience. 

Regards, 

~Leonard  

Hi Leonard,

I know that TI is a pioneer in power-saving techniques and the problems associated with thermal cycling.

I will wait for your reply and thank you in advance for your support.

Regards

Hello Alfonso, 

Thank you for your patience while I was out-of-office, and for the time to research this topic. 

The TI website you reference contains reliability FIT/MTBF references that are based on JEDEC standards, and are derived from qualification data.   These are not intended to be used for a Safety Application or a SIL rating; in short, the MTBF / FIT and information here is not the same as the Safety MTBF/FIT assessment.   Details of this can be found at this link, see FAQS.   Functional safety | ISO 26262/IEC 61508-certified | TI.com. 

The FIT/MTBF derived for devices that support functional safety is here:  Understanding Functional Safety FIT Base Failure Rate Estimates per IEC 62380 and SN 29500.

TI does support functional safety applications for many products, including MCUs.    Background on TI functional safety support and Safety-certified products can be found at this link.    https://www.ti.com/technologies/functional-safety/overview.html  . 

I hope this has been helpful. 

~Leonard