Characterisation of operational amplifier performance as a function of total ionising dose at both room and cryogenic operating temperatures for space applications

Commercial off the shelf operational amplifiers based on junction field-effect transistors and bipolar transistors were tested under gamma radiation at both room temperature and 77 K in parallel to determine their suitability for space applications. The irradiation while under cryogenic conditions simulates the environment that these devices would experience on small planetary missions where environmental control is not possible due to lack of energy generation capacity. The performance characteristics studied were: offset voltage, total harmonic distortion, change in open loop gain, and noise voltage. A single amplifier remained in specification through 100 krad(Si) and at 77 K. Differences in radiation tolerance were found between room temperature and cryogenic operation for the operational amplifiers under test. In some cases, the best performance was obtained at low temperatures while for others it was obtained at room temperature. The results highlight the need to perform these tests under operational conditions when extreme environment operation is required.