A0 . 4V6 3 W 76.1 dB SNDR 20 kHz Bandwidth Delta-Sigma Modulator Using a Hybrid Switching Integrator Y ounghyun Y oon

Abstract

This paper presents a delta-sigma modulator op- erating at a supply voltage of 0.4 V. The designed delta-sigma modulator uses a proposed hybrid switching integrator and operates at a low supply voltage wi thout clock boosting or boot- strapped switches. The propos ed integrator consists of both switched-resistor and switched-c apacitor operations and signif- icantly reduces distortion at a l ow supply voltage. V ariation in the turn-on resistance, which is the main source of distortion, is avoided by placing the switches at the virtual ground node of the amplifier. The proposed low-vol tage design scheme can replace commonly-used clock boosting techniques, which rely on internal high-voltage generation circuits. A fabricated modulator achieves a 76.1 dB signal-to-noise-plus-distortion ratio (SNDR) and an 82 dB dynamic range at a 20 kHz bandwidth. The measured total power consumption is 63 µW from a 0.4 V supply voltage. The measured results show robust S NDR performance, even at ±10% supply voltage variations. The mea sured results also show stable performance over a wide temperature range.