An evaluation of the radiation tolerance of a 32-bit microprocessor for space applications

A radiation evaluation was performed on the Intel MQ80386-20/B microprocessor to determine their total dose tolerance. Four parts were subjected to radiation exposures of 2.5, 5 and 7.5 krads(Si) at 0.01-0.02 rads(Si)/sec. Following this total dose exposure, the parts were annealed at 25°C for 1200 hours in five annealing steps. After each radiation exposure and annealing step, the parts were tested according to the test conditions and specification limits in the manufacturer´s data sheet. All four parts passed all electrical tests through the 5-krad(Si) irradiation. After 7.5 krads(Si), the parts failed all four functional tests and several output voltage tests. The parts continued to fail the functional tests and several output voltage tests throughout the subsequent annealing steps up to 1200 hours (cumulative) at 25°C. No significant sensitivity to radiation was observed in any other test parameters. It is recommended that total dose radiation testing be performed on every flight lot of these parts, since any change in the manufacturing process can significantly affect the total dose tolerance. A comprehensive test vector set which can provide the highest fault coverage should be used during the radiation testing.