Paper Info
Title
9.4 A 4<sup>th</sup>-Order Cascaded-Noise-Shaping SAR ADC with 88dB SNDR Over 100kHz Bandwidth
Abstract
High-resolution, sub-MHz-bandwidth data converters are essential for audio and sensor applications and are conventionally implemented as sigma-delta (SD) converters. The dependence of SD ADCs on op-amps inherently results in difficulties for process scaling, power efficiency improvement, and area reduction. A promising alternative to SD ADCs is the emerging noise-shaping (NS) SAR ADC, which provides high resolution with high energy efficiency and compactness. For medium-high SNR applications, some NS-SAR ADCs already exhibit better performance than SD ADCs [1, 2]. However, NS-SARs for applications that require SNR >85 dB and hundreds of kHz of bandwidth are currently lacking. The SNR is limited because most recent NS-SAR ADCs are restricted to a low-order NTF. Additionally, noise from the loop filter limits performance. In this work, we propose a cascaded-noise-shaping (CaNS) SAR architecture that cascades two 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> -order NS stages to provide a 4 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order NTF for high resolution, while consuming similar power and area to a 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> -order NS-SAR. Our prototype achieves 88dB SNDR over a 100kHz bandwidth while consuming only 120μW and occupies 0.02mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , resulting in a Schreier FoM of 177dB. The proposed architecture enables the NS-SAR to be used in low-power, area-critical audio applications in place of SD ADCs.
Year
DOI
Venue
2020
10.1109/ISSCC19947.2020.9062905
2020 IEEE International Solid- State Circuits Conference - (ISSCC)
Keywords
DocType
ISSN
power efficiency improvement,loop filter,Schreier FoM,CaNS SAR architecture,second-order NS-SAR,SD ADC,fourth order cascaded-noise-shaping SAR ADC,area-critical audio applications,cascaded-noise-shaping SAR architecture,low-order NTF,NS-SAR ADC,medium-high SNR applications,energy efficiency,op-amps,sigma-delta converters,sensor applications,sub-MHz-bandwidth data converters,SNDR,power 120.0 muW,size 0.02 mm,bandwidth 100.0 kHz
Conference
0193-6530
ISBN
Citations 
PageRank 
978-1-7281-3206-8
0
0.34
References 
Authors
0
5
Name
Order
Citations
PageRank
Jie Lu113125.58
Boyi Zheng231.80
Hsiang-Wen Chen311.03
Runyu Wang400.34
Michael P. Flynn5748.98