SMASH ΔΣ modulator with adderless feed-forward loop filter

Abstract

A novel cascade ΔΣ modulator, which combines the benefits of sturdy MASH (SMASH) topology and feed-forward loop filter, is presented. The proposed ΔΣ architecture is based on moving the power-hungry adder block from the quantiser input to the first integrator output. The proposed architecture shows a better operational transconductance amplifier (OTA) linearity and relaxed OTA DC-gain compared with conventional MASH and SMASH topologies. This feature makes the modulator topology more suitable than conventional MASH and SMASH topologies for low-voltage applications.