> A piece of trivia the Voyager space craft used the RCA 1802. 
> It was quite radiation resistant because of the rather large 
> track sizes on the silicon. Radiation would ionize a local 
> part of the processor generally without enough charge to 
> change the logic state. The 1802 was laid out on mylar like 
> an old time PC board and photo reduced then etched on 
> silicon. 

IIRC the 1802 was one of the few chips that were made in SoS (Silicon On
Saphire) process, which made it very radiation-hard.

Space stuff often uses 'old' designs, simply because those were made
with larger geometries that current designs. Large geometry == more
radiation resistant. 

Wouter van Ooijen

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Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 
 

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