ABSTRACT
This chapter proposes an analytical nonlinear op-amp dc-gain curve model. Op-amp dc-gain is nonlinear, and this can cause distortions in various applications. However, so far no efficient tool is available for analyzing dc-gain nonlinearity; the dc-gain curve can only be generated from a designed op-amp. If the dc-gain nonlinearity is too serious, one has to redesign op-amps. In practice, the op-amp dc-gain is nonlinear, and this can cause distortions in various applications. For example, the distortion resulted from nonlinear dc-gain can significantly reduce SNDR of sigma-delta modulators. In order to significantly speed up the design process, a nonlinear op-amp dc-gain curve model was proposed in, which produces dc-gain curves directly from op-amp design parameters, eliminating the need of transistor-level op-amp designs and simulations. The model can be applied to two-stage fully differential op-amp without common-mode feedback configuration by integrating the dc-gain curve.
