Design of the CMOS inverter‐based amplifier: A quantitative approach

Summary The CMOS inverter can be used as an amplifier if properly biased in the transition region of its voltage‐transfer characteristics (VTC). In this paper, the design of this amplifier is investigated with its merits and demerits illustrated and with the various trade‐offs involved in its design discussed. Specifically, the following performance metrics are discussed quantitatively: gain, area, linearity, maximum allowable swing, bandwidth, stability, noise factor, impedance matching, and slew rate. Also, the effect of process, voltage, and temperature (PVT) variations are investigated. The optimum number of stages corresponding to the minimum area required for achieving a certain voltage gain is determined. The results obtained from the quantitative analysis and the simulation are discussed. The CMOS inverter can be used as an amplifier if properly biased in the transition region of its voltage‐transfer characteristics (VTC). In this paper, the design of this amplifier is investigated with its merits and demerits illustrated and with the various trade‐offs involved in its design discussed. Specifically, the following performance metrics are discussed quantitatively: gain, area, linearity, maximum allowable swing, bandwidth, stability, noise factor, impedance matching, and slew rate.