Radiation Testing of the CMOS 8085 Microprocessor Family

Preliminary results of radiation testing are reported for parts from the SA3000 family, CMOS versions of the Intel 8085 microprocessor family. Total dose tests of the SA3000 and SA3002 have demonstrated full functionality after 3 × 106 rad (Si). Static power supply currents of the SA3000 measured after reset increased from approximately 5OμA to 500μA at VDD = 1OV while maximum operating frequency decreased from greater than 10 MHz to 4 MHz at VDD = 9V post 3 × 106 rad (Si). Output drive currents decreased 25% post 1 × 106 rad (Si) and 40% post 3 × 106 rad (Si). The nominal threshold voltage shift of discrete transistors measured under worst-case bias (n-channels, ON; p-channels, OFF) shifted -0.5 volts and -2.40 volts post 1 × 106 rad (Si) for n-channel and p-channel MOSFETs, respectively. Total dose tests on the SA3002 are also reported. Transient radiation upset levels of about 1× 109 rad (Si)/sec have been measured for all part types from this family. Latch-up immunity for this technology has been demonstrated up to 1 × 1012 rad (Si)/sec using the SA3001. Electrical bench tests on the SA3000 and SA3001 are discussed which substantiate this result. The technology used for the SA3000 family is a 3μm silicon gate process fabricated in n on n+ epitaxial silicon. Functional test programs for each chip of the family are discussed.