Continuous-time delta-sigma modulator with maximally flat signal transfer function using minimum number of DACs

This paper presents a design methodology to achieve maximally flat signal transfer function (STF) in continuous time delta-sigma modulators (CTDSMs). A 4th order CTDSM with a chain of feedback (CIFB) structure is used to achieve maximally flat STF, while the required number of digital-to-analog converters (DACs) in the traditional CIFB structure is minimized. Therefore, both high in-band dynamic range and low power/area can be achieved by using the proposed scheme. Detailed Cadence and Matlab simulations are provided to prove the operation of the proposed scheme.