The MOS capacitor amplifier

It is well known that low noise amplification can be performed by using a capacitor whose capacitance can be controlled. In this paper, it is shown that changing the inversion level of a MOS transistor allows voltage amplification. The theoretical characterization of this amplifier in terms of gain and harmonic distortion is made, and comparisons with HSPICE results are performed. Finally, some practical considerations to improve the performance of the circuit are presented.