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Re: (no subject)

On 10 Jul 1997 05:35:06 GMT, nathan@visi.com (Nathan Mates) wrote:

>In article <5q1rf3$kqr$1@enyo.uwa.edu.au>,
>Joseph Turner  <jturner@tartarus.uwa.edu.au> wrote:
>>I heard that they choose cpu's like that also cause they are less
>>susceptible to destruction by radiation..i.e. radiation from the sun
>>destroys integrated circuits...smaller technolgy being more suspectible.
>>Just something I heard.
>
>   Yep. There are certain chips rated at high resistance to radiation,
>shock (sorry, but you do not ship dinner table china on the Mars
>superball express), ease of interfacing, development & compiler
>technology, familiarity to the designers, etc. 

Processors like the 8085, the 1802, and a very small number of other
processors all share the distinction of being available in
"space-spec", the grade beyond "mil-spec".  SS parts are extended temp
range (-55C to +125C) PLUS some degree of rad-hardness.  As the design
rule shrinks, the dies become more susceptible to corrupt bits due to
radiation "events".

I once saw a 741 opamp (ubiquitous 0.10 "popcorn" IC) in space-spec
that carried a price tag of $300 or so!  I shudder to think what the
80C85 cost!

I doubt that the 80C85 would get any design wins based upon ease of
interfacing (horrible multiphase clocks, if I remember correctly) or
compliler technology, but it certainly is low power.  Unfortunately,
the tricks that designers use today to get low power usually shrink
the deisgn rule to get small transistors (so that switching currents
drop), which don't bode well for being rad hard.

-tom

-----

Thomas J. LeMense, Sr. Project Engineer
TRW Automotive Electronics Group
Farmington Hills, Michigan facility
248.615.7822 voice / 248.478.7241 fax
internet:  lemenst@fhsmtp.fh.trw.com