# Lifetime calculation based on mission profile

Discussion in 'Reliability Analysis' started by DMath, Jul 9, 2019.

1. ### DMathNew Member

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Hi,

When it comes to lifetime calculation I am always confuse.

I have this thermal operating profile as below:-
Tj = 110C (operating hours = 400hrs)
Tj = 105C (operating hours = 1200hrs)
Tj = 100C (operating hours = 1650hrs)
Tj = 95C (operating hours = 2200hrs)
Tj = 90C (operating hours = 1520hrs)
Tj = 85C (operating hours = 73hrs)

It is an actual use conditions with various of temperature operated at the specified operating hours.
The duty cycle based on the profile is that it operated at total 7043 hours per year (added all the operating hours = 7043 hours).

Assuming available stress condition (accelerating test condition) is at 125C at 1000hrs with typical voltage at 1V (accelerating voltage = 1.2V)
Can the above profile exceed the lifetime of 10 years?
In terms of lifetime calculation, should we be calculating both temperature & voltage acceleration or just temperature acceleration alone as we only have the thermal operating profile?

Hope to get the answer ASAP.