Dose-rate-independent total dose failure in 54F10 bipolar logic circuits

The ⁶⁰Co gamma ray total dose performance of unhardened bipolar 54F10 TTL (transistor transistor logic) integrated circuits was measured over dose rates from 0.0088 rad(SiO₂)/s to 28 rad(SiO₂)/s. Contrary to what others have reported on the 54F logic family, failure was independent of dose rate. This result implies that these parts are undesirable for use in a space environment. One manufacturer´s part failed due to excessive input high current at total doses from 20 to 30 krad(SiO₂) and the other failed at total doses from 7 to 9.5 krad(SiO₂). Thus, when considering a family of bipolar devices for application at space dose rates, each member of the family must be examined. It is pointed out that extrapolating total dose radiation measurements made at laboratory dose rates to sweeping conclusions about the performance of an unhardened process or device family at space dose rates can be misleading