A 1.2V 130μA 10-bit MOS-Only Log-Domain ΣΔ Modulator

This paper presents a new low-voltage MOS-only circuit technique to implement oversampling ΣΔ modulators in purely digital CMOS technologies. The basis of the proposed design strategy is a combination of log domain processing and the MOSFET operating in subthreshold. In this sense, compact circuit implementations are given for all the required basic building blocks, such as compressors, integrators, quantizers and DACs. Finally, experimental results are presented for a complete 4th-order 64-oversampling 1-bit ΣΔ modulator integrated using a standard 0.35 μm 1-polySi 3-metal digital CMOS technology.