A 0.9-V 0.2-mu w CMOS single-opamp-based switched-opamp Sigma Delta modulator for pacemaker applications

A 3(rd)-order lowpass SigmaDelta modulator operating with a 0.9-V supply voltage is realized with a standard 0.35-mum CMOS process. To achieve ultra-low-power and tiny-chip-area design, single-opamp-based SigmaDelta modulator architecture is proposed and implemented with switched-opamp technique. Employing a novel opamp design with three switching output pairs, the SigmaDelta modulator achieves a SNR of 75dB at an ultra low power consumption of 0.2muW, which is more than an order lower than existing designs