A Unity‐Gain Buffer Assisted Noise‐Shaping SAR ADC Based on Error‐Feedback Structure. Issue 4 (1st July 2022)

• Record Type: Journal Article
• Authors: YI, Pinyun; ZHU, Zhangming; XU, Nuo; FANG, Liang; HAO, Yue
• Is Part Of: Chinese journal of electronics. Volume 31:Issue 4(2022)
• Page Start: 658
• Page End: 664
• Publication Date: 2022-07-01
• Subjects: Noise‐shaping SAR ADC -- Error feedback -- Unity‐gain buffer -- Lossless integration -- Ping‐pong manner -- Full‐resolution switching; Electronics -- Periodicals; Electronics -- China -- Periodicals; Electronics; China; Periodicals; 621.38105
• DOI: 10.1049/cje.2020.00.286
• Languages: English
• ISSNs: 1022-4653

Abstract

Abstract : The passive noise‐shaping successive approximation register (NS‐SAR) analog‐to‐digital converter (ADC) demonstrates high performance in resolution improvement, power reduction, and process scaling, while its charge‐sharing loss and limited bandwidth weaken the noise‐shaping effect. This paper presents a first‐order NS‐SAR ADC based on error‐feedback (EF) structure to realize high‐efficiency noise shaping. It employs a lossless EF path by using a set of ping‐pong switching capacitors with passive signal‐residue summation technique. The proposed first‐order EF NS‐SAR prototype can be promoted to multi‐order structure with the minor modification. Verified by simulation in 65‐nm CMOS process, the proposed 9‐bit NS‐SAR ADC consumes 183.66 μ W when operating at 20 MS/s with the supply voltage of 1.2 V. At the oversampling ratio of 16, it achieves a peak signal‐to‐noise‐and‐distortion ratio of 81 dB, yielding Schreier figure of merit of 176.32 dB.