Settling behavior of operational amplifiers (opamps) is important in many analog signal-processing applications. In this paper, the analysis of single-stage opamps based on settling time has been performed. A simple yet accurate model for the settling response of first-order opamps that modifies conventional models is proposed to revise the equations. The presented approach leads to a new simple settling-based design methodology for single-stage operational amplifiers. Circuit-level simulations demonstrate the effectiveness of the procedure.