Large signal analysis of low-voltage BiMOS analog multipliers using fourier-series approximations

This paper discusses the large signal performance of BiMOS low-voltage analog multipliers. Fourier-series approximations are obtained for the transfer characteristics of the basic building blocks, such as the BiMOS folded Gilbert multiplier cell, the squaring multiplier made from two cross-coupled emitter-coupled pairs and driven by an MOS quadritail, and the tripler made from cross-coupled emitter-coupled pairs and driven by an MOS quarter-square multiplier. Using the Fourier-series approximations of the transfer functions of these basic building blocks, closed-form expressions are obtained for the amplitudes of the harmonics and intermodulation products at the output of these analog multipliers when excited by multisinusoidal input signals. Using these expressions, comparison between the large signal performance of these analog multipliers can be made and the parameters required for a predetermined performance can be determined.