An asynchronous sub-two-step quantizer for continuous-time sigma-delta modulators

• Main Authors: Tan, Xiao Liang, Chan, Pak Kwong, Dasgupta, U.
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electronic circuits
• Online Access: https://hdl.handle.net/10356/103213; http://hdl.handle.net/10220/25740
• Institution: Nanyang Technological University

This paper presents an asynchronous sub-two-step circuit architecture to reduce the complexity and power consumption of internal analog-to-digital converter (quantizer) for Continuous-Time Sigma-Delta Modulator (CTSDM). By using the proposed new circuit topology, only 1/3 of comparators for a 5-bit quantizer design are needed when compared with the conventional flash based counterpart. The proposed quantizer has been implemented and fabricated in a UMC 65-nm CMOS process. The measured results have shown that the quantizer consumes 0.59 mW at an operating frequency of 250 MS/s in a 1.2 V supply and achieves 28.82 dB SNDR (4.5 ENOB) from the output spectrum.