Large Signal Analysis of Low-Voltage Bipolar Analog Functional Elements using Fourier-Series Approximations
Muhammad TaherAbuelma’atti · Frequenz · 1999
This paper discusses the large signal performance of low-voltage analog functional elements built around bipolar-junction transistors. Fourier-series approximations are obtained for the transfer characteristics of the basic building blocks; such as the balanced emitter-coupled pair, the unbalanced emitter-coupled pair with different transistor sizes, the emitter-coupled pair with bias offset and the triple-tail cell. Using the Fourier-series approximations of these basic building blocks, closed form expressions are obtained for the amplitudes of the harmonics and intermodulation products at the output of analog functional elements; such as the basic differential pairs, squaring circuits, operational transconductance amplifiers, multipliers, mixers and triplers, excited by a multisinusoidal input signal. Using these expressions comparison between the large signal performance of analog functional elements can be performed and the parameters required for a predetermined performance can be determined.