A Battery-Powered Wireless Ion Sensing System Consuming 5.5 nW of Average Power

• Published in: IEEE journal of solid-state circuits Vol. 53; no. 7; pp. 2043 - 2053
• Main Authors: Hui Wang, Xiaoyang Wang, Barfidokht, Abbas, Jiwoong Park, Wang, Joseph, Mercier, Patrick P.
• Format: Journal Article
• Language: English
• Published: IEEE 01.07.2018
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">in vitro; Batteries; Biosensing; Electrodes; ion-selective electrodes (ISEs); Ions; near-zero power; power oscillator; reference-free SAR analog-to-digital converter; relaxation oscillator; Sensors; Sodium; ultra-low-power; Wireless communication; Wireless sensor networks
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2018.2815657

This paper presents a battery-powered wireless ion sensing platform featuring complete sensing-to-transmission functionality. A 1 mm × 1.2 mm chip fabricated in 65 nm includes a 406 pW potentiometric analog front end, a 780 pW 10-bit SAR ADC, a 2.4 GHz power-oscillator-based wireless transmitter that consumes an average of 2.4 nW during a 10-sample/sec transmission rate, two timing generation oscillators that each consume 140 pW, and a 3:1 switched-capacitor dc-dc converter with 485 pW of quiescent power that achieves the efficiencies of 96.8% and 70.5% at 60 and 3.9 nW loads, respectively. The chip connects to a screen-printed ion-selective electrode responsive to sodium ions, and in vitro testing across an NaCl solution concentration range of 0.1-100 mM exhibited a linear near-Nernstian response with a slope of 71 mV/log10[Na + ]. When all blocks are operating, the system consumes an average of 5.5 nW.