Methods of Increasing Voltage Gain of the Low-Voltage Classical Stages

Analysis of architectural and circuit limitations on voltage gain (Gain) of the classical stages with a common base and a common emitter at a low-voltage supply are considered. It is also considered methods of improving voltage gain which are based on the principles of their mutual compensation impedances that have a negative impact on voltage gain. The mathematical conditions of presented methods are also considered. The paper consider problem of limiting voltage gain stage with a common base, method of the current compensation of the impedance of the collector load, method of mutual compensation of the collector load impedance in the stages with a common base and method of increase voltage gain in stage with a common emitter. The considered features of the design of the compensation circuits show that this circuit solution is quite promising on the SiGe process, in which the p-n-p transistors are not realized.