Fully Differential Difference Amplifier for Low-Noise Applications

In this paper, a fully differential difference amplifier designed in 0.35 μm CMOS technology is presented. The proposed amplifier reaches high dynamic range and low input noise. Comparison of noise performance of the proposed fully differential difference amplifier to an ordinary differential amplifier has been performed. Simulation results prove that the developed amplifier circuit can be advantageously used in applications that require a fully differential signal. In our work, the proposed amplifier has been experimentally employed in the analog front end of the readout interface for a MEMS (Micro-Electro-Mechanical-Systems) capacitive microphone.