Design and Comparison of Very Low-Voltage CMOS Output Stages

This paper analyzes and compares CMOS output stages for very low-voltage operational amplifiers. The analysis was carried out by taking into account output stage performance parameters which also affect the characteristics of the overall amplifier. In particular, three quality factors were defined to afford the designer a better understanding of the relationships between current dissipation, area consumption, bandwidth, and linearity. Exploiting these new parameters, four output stages were analyzed in detail and compared. Finally, comparison results were validated by simulations.