TLE2022-Q1 Input offset voltage long-term drift specification

Answer for Q1: yes it is uV/month

I' m still checking for Q2 and will post the answer soon. 

Hello Mahmoud-san,

Thank you for your usual support.

Could you please answer following questions instead of above questions.

Customer is considering to use TLE2022-Q1 for their ECU and needs answer.

Q1:

I considered your Arrhenius calculation and I think attached should be correct.

Arrhenius equation - confirmation.docx

Could you check attached file and advise me which is correct.

Q2:

According to your calculation, 168h/150C stress test is equivalent to 258,287 months/25C.

258,287 months is 21,524 year.

(In case of my calculation is correct, 168h/150C stress test is equivalent to 14,784 months/25C.

14,784 months is 1,232 year.)

Please advise why TI did acceleration test that is equivalent to so long duration (21,524 year, 1,232 year).

Q2:

Please advise test method of 168h/150C acceleration test.

Is the device left in constant 150C ambient with bias like JESD22-A108?

Best Regards.

Hello Mahmoud-san,

Thank you for your answer.

Please try to find the reason of long duration.

Best Regards.

Hello Mahmoud-san,

Please answer remaining question about the reason of long duration.

Best Regards.

The acceleration factor is an exponential function and changes rapidly with ambient temperature. In automotive environment the ambient temperature is mostly high.

The acceleration factor at 75C, for example, is 296 and the service time is 296 x 168 =  49728 hours or 69 months.

Hello Mahmoud-san,

Thank you for your answer.

You explained service time at 75C is 69 month.

Please confirm if following my understanding is correct.

Long term drift at 25C service time is 0.005uV/mo typical, so long term drift at 75C could be calculated as follows.

Long term drift at 75C = 0.005uV/mo x (14,784 months/69 month) = 1.07 uV/mo typical

Best Regards.

Hello Mahmoud-san,

Could you answer following additional question from customer?

“Offset drift/month” is calculated by “offset change/service month”.

This calculation means drift increase constantly by month.

Could you please explain the reason to use above calculation (calculation means drift increase constantly by month) using long-term drift occurrence mechanism of TLE2022 (what material will change how) ?

Best Regards.

Hello Mahmoud-san,

Could you please answer my question dated Fri, Oct 14 2016?

Best Regards.

Toshio-san, If I understand correctly your question, the drift calculation is an average. That means we measure the long term offset using acceleration. The Arrhenius equation help to calculate the average change per month (assuming it is linear). The offset change verses time is linear and the slope is dVos/dt = 0.005uV/mo.  

Hello Mahmoud-san,

Thank you for your reply.

Customer supposes that offset change verses time is linear (as you explained) from how TI calculate 0.005uV/mo using operating life test result.

Could you explain the reason of “offset change verses time is linear” using drift mechanism of TLE2022 (what material will change and how)?

Best Regards.