R-C Ladder Design: A Tutorial [CAS Education]

Passive ladder networks are used in many applications for signal processing such as anti-aliasing filtering, ripple reduction in power networks, and as loop filters in micro-power delta-sigma analog-to-digital converters. In this tutorial, we provide an update on the theory and design of some commonly used passive R-C ladders. The discussion starts with the description of the transfer functions of two-ports, followed by the analysis of a cascade of two-ports, including the special case of identical two-ports. We discuss the estimation of thermal noise in passive ladders. Finally, a simple example is used to illustrate the application of the theory to the design of an R-C ladder with a prescribed transfer function and signal-to-noise ratio.