Exceeding the input or output swing limitations on amplifiers causes distortion on the output signal. This document initially covers the basic methods for calculating these limitations. Next, a simplified explanation of how the limitation occurs on internal transistor topology is covered. The internal operation is described to provide insight to the board-and-system level designer on how different categories of amplifiers behave. For example, the operation of two different types of rail-to-rail common-mode range are compared and contrasted. Each of these topologies has specific advantages and disadvantages related to noise and distortion. Finally, the impact of output current on swing limitations, short-circuit protection, and other topics related to the op amp input and output stage are covered.