Don Hyde wrote:
>
> Last year I went to the uChip Master's, and this question came up.  The
> answer then was:
>
> The difference is testing -- or more accurately, passing the tests.
>
> They set out to make all the chips work at 20 MHz, full industrial range.
> After the first few batches, pretty much all of them do make it.  But, if
> there are any changes in the process, frequently, for a while, more chips
> fall in the 4MHz commercial bin, and less make it to the 20MHz industrial
> bin.
>
> When you pay for faster parts and industrial temp range, it's not so much
> the testing (they likely all got the same testing).  You are paying for
> Microchip's guarantee that they meet the spec you bought to.
>
> Pretty much all parts work that way.  That's why the fine print says "meets
> or exceeds..."


So really, the 4MHz parts and 10MHz parts are the ones that
the manufacturer has found to be faulty, or MORE faulty.
Do the failures that cause them to be sold as reduced speed
parts have any other effects? ie, whatever die problems
caused it to fail, could cause other unreliability??

I'm glad we are only buying 20MHz parts now. I wouldn't
want to put reject parts in our products.
-Roman

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