At 03:31 AM 11/12/2009, David Smith wrote...
The LPRO-101 blurb says:
Amb.Temp: 20 °C 25 °C 30 °C 40 °C 50 °C 60 °C
MTBF (hrs) 381k 351k 320k 253k 189k 134k
A year is 8760 hours (ignoring leap
years). Call that 10K. So they
expect
25 years at 40C and 32 years at 30C.
That's calculated MTBF. YMMV.
I'm sure someone with more statistics background
can add to this, but useful (or expected)
lifetime cannot be determined from an MTBF number.
Here's an example I found, demonstrating this:
"There are 500,000 25-year-old humans in the sample population.
Over the course of a year, data is collected on
failures (deaths) for this population.
The operational life of the population is 500,000
x 1 year = 500,000 people years.
Throughout the year, 625 people failed (died).
The failure rate is 625 failures / 500,000 people
years = 0.125% / year.
The MTBF is the inverse of failure rate or 1 / 0.00125 = 800 years.
So, even though 25-year-old humans have high MTBF
values, their life expectancy
(service life) is much shorter and does not correlate."
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