Behavioral modeling of switched-capacitor sigma--delta modulators

This paper presents a complete set of blocks implemented in the popular MATLAB SIMULINK environment, which allows designers to perform time-domain behavioral simulations of switched-capacitor (SC) sigma--delta ([SIGMA][DELTA]) modulators. The proposed set of blocks takes into account most of the SC [SIGMA][DELTA] modulator nonidealities, such as sampling jitter, kT/C noise, and operational amplifier parameters (white noise, finite dc gain, finite bandwidth, slew rate and saturation voltages). For each block, a description of the considered effect as well as all of the implementative details are provided. The proposed simulation environment is validated by comparing the simulated behavior with the experimental results obtained from two actual circuits, namely a second-order low-pass and a sixth-order bandpass SC [SIGMA][DELTA] modulator. Index Terms--Analog--digital conversion, discrete-time systems, sigma--delta ([SIGMA][DELTA]) modulation.