Re: Operating temperature derating

On Fri, 7 Jun 2024 15:16:49 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

On 6/7/2024 2:59 PM, legg wrote:

On Fri, 7 Jun 2024 12:45:24 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:
 

On 6/7/2024 6:35 AM, legg wrote:

Commercial considerations of free enterprise have always pushed
human behaviour towards banditry, so what can I tell you?

>
But banditry would suggest taking advantage of the customer.
This is the opposite; the customer gets *more* performance
than the stated capabilities.
>
But, no way to know HOW MUCH more!

 
What exactly IS your concern?

>
I want too know how much MORE than the published/unpublished operating
limits one can reasonably expect from a piece of kit -- given that
these limits don't seem to TRULY represent "maxima".
>
We have a general idea of the types of components used in these
things and realize that their operating limits usually exceed the
published limits for the composite device -- often by a lot!
>
This suggests (to me) that the published limits aren't backed by
"real" engineering or stress testing.  But, rather, likely arise
from marketing specs... someone making a SWAG as to how customers
will LIKELY use the devices and not what their actual design limits
happen to be.
>
[Given that using ANYTHING beyond its operating limits leaves you
without a leg to stand on, it would be nice to have some idea as to
what a reasonable expectation for those limits might be, despite
the "fluff" on the spec sheet.  E.g., I would be really pressing my
luck to use something at 80C in that most components would likely
not be specified at those extremes.  But, 55C for a 50C-specified
device?  60C?]

Given that you expect to get what's promised when you pay for it,
outside of banditry, I only expect performance and a reasonable
service life.

I often kick mysellf in the head when I realize that shortcomings
in product performance were actually predicted in the written
specification - that the performance that I was expecting was not
only outside published spec, but might not be physically
possible, using current materials and techniques.

RL