A Noise Coupled ΔΣAD Modulator Using Passive Adder Embedded Noise Shaping SAR Quantizer

Chunhui PAN  Hao SAN  

IEICE TRANSACTIONS on Electronics   Vol.E101-C    No.7    pp.480-487
Publication Date: 2018/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E101.C.480
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Their Application Technologies)
ΔΣAD modulator,  SAR ADC,  noise coupling,  

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This paper presents a 3rd-order ΔΣAD modulator with noise coupling structure using the proposed passive adder embedded quantization noise shaping (QNS) SAR quantizer. QNS SAR quantizer can feedback shaped quantization noise and realize an additional 1st-order noise shaping by noise coupling technique. As a result, the 3rd-order noise coupled ΔΣAD modulator is realized by two integrators with ring amplifier and the QNS SAR quantizer. The SPICE simulation results demonstrate the feasibility of the proposed ΔΣAD modulator in 90nm CMOS technology. Simulated SNDR of 81.05dB is achieved while a sinusoid -4.32dBFS input is sampled at 100MS/s and the bandwidth is BW=3.125MHz. The total power consumption in the modulator is 4.58mW while the supply voltage is 1.2V.