Influence of ionizing radiation on the parameters of an operational amplifier based on complementary bipolar transistors

Resumo

The influence of a 4 MeV energy electron flux and 60Co gamma radiation with an average energy of 1.25 MeV on the characteristics of silicon complementary bipolar transistors (BTs) and a wide-band operational amplifier (OA) has been studied. It is established that an action of F_E = 3×10¹⁴ el/cm² electron fluence causes a decay in the common–emitter current gain (ß) of 61% for NPN and 66% for PNP transistors, as well as a decrease in the maximum value of the transition frequency (f_T) of 12% for NPN and by 4% for PNP transistors. When the absorbed dose D_G amounts to 3 Mrad, a decrease in ß by 39% for NPN and by 44% for PNP transistors, and in f_T of 10% for NPN and 11% for PNP transistors is observed. Despite the substantial decay in ß of transistors, the OA circuitry provided the retention of the operation speed and a small decrease in the offset voltage (about 1.5 mV) in the irradiation range mentioned. The circuitries of OA cascades and the experimental characteristics of the BTs and OAs are presented.