Analysis of the settling behavior of an operational amplifier

The settling behavior of a pole-splitting compensated operational amplifier is analyzed using a second-order (two-pole) transfer function. It is shown that although the slewing period of the amplifier is well approximated by the commonly used formula for slew rate, the settling behavior after the slewing period can only be fully explained using a second-order transfer function. Simple criteria relating the circuit parameters to the damping ratio of a second-order feedback system are given. Analytical expressions for the amplifier responses and settling times are derived. The analysis is justified by close correspondence with computer simulations.