Total dose response of STL and I2L logic devices

Total dose effects on nine Schottky Transistor Logic (STL) and Integrated Injection Logic (I2L) LSI commercial circuits are discussed. The devices were developed to perform Global Positioning System functions. The I2L devices showed some radiation sensitivity in output load voltage at high output load currents but were functional at lower output currents to the maximum test level of one million rad (Si), STL devices were relatively unaffected by the radiation. A diagnostic use of total dose testing is discussed. The test results of a hardened redesign of one of the circuits are shown.