*Hi, Im a reliability engineer, im reading the Reliability Handbook written by Analog. I have a question about the first example on the "Failure Rate Calculation" on page 14-15. *

*Im plugging in the numbers on the equation to see if I get the same, and Im not. I do get the same results for the acceleration factor using the Arhenius equation, but im not sure how the "No. of Device Hours at Test Temperature" and the "Equivalent Device Hours at 55°C" are calculated. *

*This is the formula for the first one:*

*Ndt = Nd × Nh × AT*

*Ndt=77*168*77 using the first component AD7357. *

*The results are different on Table 4, and im not sure for which component are those calculations.*

*Is it possible to get this explained?*

*Thank you,*

*Daniela*