A 1V 77dB-DR 72dB-SNDR 10MHz-BW 2-1 MASH CT ΔΣM

摘要

ΔΣM performance can be improved by using MASH or SMASH structures to obtain higher-order noise shaping [1]. They have better stability than single-loop structures. The power dissipation of ΔΣMs can be reduced by using simpler amplifiers such as single-stage or inverter-based amplifiers [2]. Selecting a passive or active-passive ΔΣM architecture, where the processing gain of comparator is used in the feedback loop of the ΔΣM's filter [3], allows a reduction in the number of amplifiers and their gain. This solution is very appealing for deep-nanometer CMOS technologies, because a comparator can achieve large gain through positive feedback, which improves with faster transistors. This paper presents a passive-active CT 2-1 MASH ΔΣM using RC integrators, low-gain stages (-20dB) and simplified digital cancellation logic (DCL). The ΔΣM, clocked at 1GHz, achieves DR/SNR/SNDR of 77/76/72.2dB for input signal BW of 10MHz, while dissipating 1.57mW from a 1V supply.