[time-nuts] Simulation

J. Forster jfor at quik.com
Sat Aug 14 17:05:37 UTC 2010


I think this is pretty common with transistors.

A company is making a particular part, then a new, "better" part comes
along that exceeds the spec of an existing part. So they start putting the
new die into the old package as well as making the new part. Fewer dice to
make likely means cheaper and less hassels. And they don't tell anyone.

Win-win, except the new part has a much higher Ft for example and formerly
stable circuits now oscillate badly. Tilt!

-John

=============


> Hello,

[snip]
> Another story is about 2N3771 transistor, initially a single-diffussed
> part, but later an epitaxial base part - with a lot more gain bandwidth
> product. But since the 'new' 2N3771 meets and exceeds original 2N3771
> specs, the same part number was used - but the part is quite different
> (and published specs continues being the JEDEC ones). So you can imagine
> that in some applications it would be quite a lot of difference if you
> breadboard with the older, and during the manufacturing phase you
> (probably without knowing it) switch to the new part.
[snip]

> Best regards,
>
> Javier





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