Two-Stage OTA Design Based on Settling-Time Constraints

The transient response of a feedback two-stage OTA is analyzed in terms of Slew-Rate and Gain-Bandwidth Product. An expression for the Settling Time is carried out. The results are then used to propose a design procedure for the two-stage OTA. The procedure is based on "settling time constraint" and on the use of the gm-over-ID ratio so to maximize the nodes voltage swing. The theory is validated by means of simulations and so is done for the design procedure.