The new architectures of the class AB differential stages for the high-speed CMOS-BiJFET of the operational and differential difference amplifiers of the sensor analog interfaces
Ilya V. Pakhomov, D. V. Medvedev, Anna V. Bugakova, Valery Petrovich Dimitrov · 2017
The article considers the designed double-ended in the inputs and the current outputs class AB multichannel differential stages (MDS), intended to the work in the operational (op-amp) and differential difference (DDA) amplifiers, including at the low temperatures and the radiation exposure. The features of the considered MDSs is absence of the classical reference current sources, setting the steady-state behavior of the input transistors, and also the wide range of the active operation. The last quality is one of the conditions of the significant increase of the maximum slew rate of the op-amp and DDA (SRout). The suggested MDSs also don't impose the restrictions on the SRout, caused by the so-called “dynamic asymmetry” of their input stages (IS), which is connected with the inertance of the emitter (source) voltage followers, present in the structure of the IS of the high-speed op-amps. There are no followers in the considered MDS. This enables to obtain the maximum high-speed response of the op-amp (DDA) in the large signal operation, corresponding to their small signal operation conditions. The authors give the examples of construction of the studied DDA and op-amp based on the JFET-CMOS MDS. They present the simulation results of the op-amp with MDS for the XFab technological process, which show, that in the micro regime of the MDS (6÷100μA) the maximum slew rate lies in the range of 260-700 V/μs. The suggested architectures of the MDS enlarge the view of the design engineers about the new methods of construction of the input stages of the analog IP-modules for the systems-on-a-chip and add significantly to the classical circuitry of the op-amp and the DDA, realized on the base of modern technologies.