Non-Ideal Issues Analysis in a Fully Passive Noise Shaping SAR ADC

Zhijie CHEN  Peiyuan WAN  Ning LI  

IEICE TRANSACTIONS on Electronics   Vol.E102-C   No.7   pp.538-546
Publication Date: 2019/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2018CTP0003
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuits and Their Application Technologies)
fully passive,  charge-redistribution,  SAR ADC,  passive gain,  noise transfer function,  

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This paper discusses non-ideal issues in a fully passive noise shaping successive approximation register analog-to-digital converter. The fully passive noise shaping techniques are realized by switches and capacitors without operational amplifiers to be scalable and power efficient. However, some non-ideal issues, such as parasitic capacitance, comparator noise, thermal noise, will affect the performance of the noise shaping and then degrade the final achievable resolution. This paper analyzes the effects of the main non-ideal issues and provides the design reference for fully passive noise shaping techniques. The analysis is based on 2nd order fully passive noise shaping SAR ADC with an 8-bit architecture and an OSR of 4.