John Payson wrote:
>
> > I guess I ought to know this but I never really found out: do companies
> > making regular commercial grade components usually test each component in
> > some way??! I never exepected that, I always thought that components for
> > non-critical applications (i.e. consumer electronics) were only spot
> > checked. I could understand maybe testing each one of the industrial or
> > aerospace/military versions for saftey's sake (although, you would also
> > expect the final equipment manufacturer to test each final device under
> > these circumstances).
>
> In many cases, testing individual devices merely to see if they meet cust-
> omer specifications is not terribly useful;

<Lots of interesting stuff snipped>

I would expect that for the OTP parts there is wafer testing, combined
with some kind of statistical quality control.

It is possible to estimate the upper and lower limits of reliability
given a random sample of devices to test. I can't remember the details
but I'm sure any undergraduate stats textbook can provide them.

I would expect the JW parts to undergo more stringent testing because
they are expected to work over the full operating range. In addition, if
I worked for Microchip, I would make damn sure the development chips
worked since one dud one could cancel a project using thousands of OTP
parts.

Just a few monday morning thoughts (before my brain gets started |-)

Keith.