A 0.6-V 540-nW delta-sigma modulator for biomedical sensors

This paper presents an extremely low-power delta-sigma modulator for battery-powered biomedical sensors. Distributed feed-forward architecture is used to achieve efficient operation at a supply voltage of 0.6 V. In order to achieve a wide input range in this low voltage environment, the bulk-driven operational transconductance amplifier is designed with a self-cascode output stage. The modulator has a dynamic range of 52 dB with only 540 nW of power for the 250-Hz bandwidth. Such a significant reduction in power consumption allows diverse battery-powered biomedical applications that have limited battery power, such as the electro-oculogram, electroencephalogram, and electrocardiogram.