Re: DS20L

["Robert M. Riches Jr." <rm riches verizon net>]

> From: "Chris Eleveld (Sector 7 Group)" <Chris_Eleveld@sector7.com>
> Date: Fri, 31 May 2002 10:28:15 -0500
>
> mostly off topic:
> I've noticed a lot of equipment has a lower end on the temperature rating.
> My ignorant self thought electronics ran better the colder they got?

MOS devices do run faster at lower temperatures.  Most aging
effects are reduced at lower temperatures, also.

One reason for a lower temperature rating is humidity and
moisture condensation.  You don't want liquid water on or in
any electromechanical devices (except inside a liquid cooling
system, of course).

Another reason for a lower temperature rating is timing
conditions inside the integrated circuits.  Different circuits
inside the chip change relative timing delays differently at
different temperatures.  There are many situations where a set
of circuits works within a range of temperatures but fails to
function correctly under either excessively hot or cold
conditions.  Also, there are some circuits that simply become
too fast at low temperatures and won't work as intended.  The
task of designing high-performance circuitry becomes much more
tractible if the operating temperature range is constrained at
both ends.  Does it sound like I've seen situations where too-
fast circuits failed?  :-)

Robert Riches
rm.riches@verizon.net