On fully differential and complementary single-stage self-biased CMOS differential amplifiers

The paper presents and analyzes three fully differential and complementary self-biased CMOS amplifiers. The three differential amplifiers are based on standard single-stage inverter, telescopic cascode and folded cascode amplifier topologies and are truly self-biased via negative feedback in the bias loop thus eliminating the need for a voltage reference. This adaptive biasing attenuates process, supply voltage and temperature variations. The folded cascode-based amplifier possesses also an increased immunity toward common-mode components in the input signal. All three differential amplifiers are comparatively analyzed by means of low frequency calculations and circuit simulations. Finally, discussed amplifiers with high gain and PVT immunity are well-suitable for implementation in nanometer CMOS processes.