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

Yeah, it was also fast and expensive. They also did CMOS RAM chips, and I 
suspect the CMOS ROM chips as well.

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

That is one factor, but also the costs involved in getting new parts 
certified as radiation hardened.

Still using OP400 op-amps and other analogue parts from the same families. 
Many of the digital parts come under ITARS regulations when attempting to 
source US made parts, so that becomes another hassle ... 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist