Generalized admittance matrix model of fully-differential VCVS

Abstract

This paper proposes a new admittance matrix model to approach the behavior of a fully-differential voltage controlled voltage source at low-frequency. The new model is simpler than that reported in the literature, because it not only can directly be used to fill the admittance matrix without extra variables, including gain and input-output impedances, but also the new stamp has few nonzero elements. Our results indicate that the proposed model can directly be used into a standard nodal analysis, obtaining a reduced and sparse system of equations. Two analysis examples are provided, showing that fully-symbolic transfer functions of a single-ended and balanced differential amplifier can be computed by using nodal analysis. But even, the symbolic expression of the common-mode rejection ratio of the differential amplifier is also computed. As a consequence, the computational complexity during the solution of the system of equations is reduced when recursive determinant-expansion techniques are applied.