Where do you get space rated components

I had to meditate on this a bit, but what you say makes sense. The radiation can easily generate carriers in the base of a lateral device. Now why PNP and not NPN is something I don't see. Well there would be higher mobility in the N-base, but that is of majority carriers, not really relevant to bipolar.

I found this out of EE Times. SOI should be great for rad hard.

Basically what you are trying to do is avoid the situation where radiation generates carriers in the substrate. When you go to epi as opposed to bulk, it is harder to create the carriers due to the heavily doped epi layer. When you go to SOI, you get rid of all those parasitic junctions.

You would have to look for parts done on a DI or SOI process. AMD does much in SOI, but you really don't put a uP in the radiation (I presume). Rad hard to most people just means operation in space and not ...well...getting ugly with particles. That Harris/Intersil/ Elantec process DI process seems to still be in production, even with all the buyouts.

Speak for yourself ;-) ...Jim Thompson