Optimum design of low-pass switched-capacitor ladder filters

Abstract

A general technique for realizing Bruton's LDI transformation in low-pass switched-capacitor ladder filters is presented, which results is switched-capacitor integrators that are insensitive to parasitic capacitances. It is shown that the correct filter response may be obtained by realizing only the stable poles of the LDI transformed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</tex> network. Realization of these "stable" poles is reduced to the problem of solving a system of nonlinear equations. The design of a third-order Chebyshev low-pass filter is presented as an example.