Time-domain 1/f noise analysis of a charge-redistribution Track-and-Hold circuit

Abstract

Track-and-Hold (T&H) circuits are used in a variety of applications. Noise is a key parameter in a T&H and can be traded for settling time or power consumption. The classical T&H noise design methodology considers only white noise sources, neglecting low-frequency noise sources. Although low-frequency noise contributions have been analyzed in the literature, an insightful, design-oriented analysis for flicker noise that can also be extended for arbitrary noise sources has not been proposed yet. In this work, we present a time-domain noise analysis for a charge-redistribution T&H circuit. The analysis considers the noise contribution from white and 1/f sources. A design-oriented expression to compute the excess noise power due to flicker noise, as a function of the sampling rate, the intended T&H resolution, and the noise parameters, is obtained. This expression shows how the relative contribution of flicker noise with respect to the total noise depends on the T&H design parameters. A simplified expression resulting from a series of assumptions allows to assess the relative contribution of flicker noise during an early stage of the design flow.