Modeling and simulation of low-power and low-voltage delta-sigma modulators

A systematic study of low-power and low-voltage delta-sigma modulators is presented, based on a device-level modeling and a simulation method using Spice. The proposed modeling technique is also well suited to build a circuit-reduction macromodel of delta-sigma modulator. The low voltage and low-power delta-sigma modulator is implemented with the switched op-amp technique in a standard CMOS technology. Simulation results of the low-voltage circuit building blocks, such as a class AB operational transconductance amplifier and a regenerative comparator are presented. The influence of different parameters on these circuit building blocks is discussed. The optimal parameters and the corresponding performance are presented, offering a valuable help for the design of sigma-delta analog-to-digital converters.