The accounting of the simultaneous exposure of the low temperatures and the penetrating radiation at the circuit simulation of the BiJFET analog interfaces of the sensors
The article considers a choice of CAD system and SPICE-models for the circuit simulation of characteristics of the bipolar (BiJFET) analog integrated circuits (IC) at the exposure of the penetrating radiation (PR) and the low temperatures. The authors suggest a modified SPICE-model, which describes the nonmonotonic change of the peak drain current and the slope of the p-n junction FET (JFET) within the temperature range from −200°C to 30°C.
The high-speed BiJFet of Op-Amps with reconfigurable architecture
A new architecture of the BiJFet of Op-Amps is proposed, in which the non-linear operating conditions of the input (DS) and intermediate (DP) stages are eliminated, when they work in the large-signal operation. As a DS, we use a scheme of class «AB» on BiJ and BiJF transistors with different principles of action. In the intermediate DP on the BiJT “folded” cascode an automatic switching of the signaling channels is provided depending on the numerical values of the DS output currents. This forces the process of recharging the balancing capacitor of the Op-Amps by eliminating the non-linear DP mode. In aggregate, the new circuit solutions provide the maximum slew rate of the BiJFet of Op-Amps with a unity gain frequency of about 100MHz at the level of 2500–2800 V/μs at high radiation and low-temperature stability of the systematic component of the offset voltage (Voff <1.5 μν, the neutron flux up to Fn <10<sup>18</sup> n/m<sup>2</sup>, T= 83°K–303°K).
Influence of ionizing radiation on the parameters of an operational amplifier based on complementary bipolar transistors
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 FE = 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 (fT) of 12% for NPN and by 4% for PNP transistors. When the absorbed dose DG amounts to 3 Mrad, a decrease in ß by 39% for NPN and by 44% for PNP transistors, and in fT 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.