1 V all-MOS /spl Sigma//spl Delta/ A/D converters in the log-domain

This paper presents novel low-voltage all-MOS analog circuit techniques for the synthesis of oversampling /spl Sigma//spl Delta/ A/D converters. The new approach exploits the possibilities of log-domain processing by using the MOSFET in subthreshold operation. Based on this strategy, a complete set of very low-voltage (down to 1 V) low-power (below 100 /spl mu/W) all-MOS basic building blocks is proposed. As a result, oversampling /spl Sigma//spl Delta/ A/D converters can be fully implemented in digital VLSI technologies for low-frequency (below 100 kHz) applications, like implantable sensors and hearing aids. Examples are given for a digital 0.35 /spl mu/m CMOS VLSI process.