A Design of 8 fJ/Conversion-Step 10-bit 8MS/s Low Power Asynchronous SAR ADC for IEEE 802.15.1 IoT Sensor Based Applications

Deeksha Verma, Khuram Shehzad, Danial Khan, Qurat Ul Ain, Sung Jin Kim, Dongsoo Lee, Younggun Pu, Minjae Lee, Keum Cheol Hwang, Youngoo Yang, Kang Yoon Lee

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

An energy efficient, low-power 10-bit asynchronous successive approximation register (SAR) analog-to-digital (ADC) converter with the sampling frequency of 8 MS/s is presented for IEEE 802.15.1 IoT sensor based applications. An improved common mode charge redistribution algorithm is proposed for binary weighted SAR ADC. The proposed method uses available common mode voltage (VCM) level for SAR ADC conversion, and this method reduces the switching power by more than 12% without any additional DAC driver as compared to merged capacitor switching (MCS). Mathematical analysis of the proposed switching scheme results in the lower or equal power consumption for every digital code as compared to MCS. A two stage dynamic latched comparator with adaptive power control (APC) technique is used to optimize the overall efficiency. Furthermore, to minimize the digital part power consumption, a modified asynchronous SAR logic with digitally controlled delay cells is proposed. High efficiency with low power consumption makes it suitable for low power devices especially for IEEE 802.15.1 IoT sensor based applications. The proposed prototype is implemented using 1P6M 55 nm complementary metal-oxide-semiconductor (CMOS) technology. The measurement results that the proposed circuit achieves are 9.3 effective number of bits (ENOB) with signal-to-noise and distortion ratio (SNDR) of 58.05 dB at a sampling rate of 8 MS/s. The power consumption of SAR ADC is $45~\mu \text{W}$ when operated at 1 V power supply.
Original languageEnglish (US)
Pages (from-to)85869-85879
Number of pages11
JournalIEEE Access
Volume8
DOIs
StatePublished - Jan 1 2020
Externally publishedYes

ASJC Scopus subject areas

  • General Engineering
  • General Computer Science
  • General Materials Science

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