A general relationship between amplifier parameters, and its application to PSRR improvement

A general relationship between the gains of multiterminal amplifiers is derived. This approach generates a constraint for the simultaneous improvement of the common-mode and the power-supply rejection ratio of the simple operational amplifier. This constraint can be relaxed by either adding a supplementary input terminal to the amplifier circuit or using a fully differential design. The method can be used to improve the power-supply rejection ratios in operational amplifiers. Several implementations of a two-stage operational amplifier illustrate this technique. >