Title :
A 0.8 µW 8-bit 1.5∼20-pF-input-range capacitance-to-digital converter for lab-on-chip digital microfluidics systems
Author :
Yanjie Xiao ; TanTan Zhang ; Pui-In Mak ; Man-Kay Law ; Martins, Rui P.
Author_Institution :
State Key Lab. of Analog & Mixed-Signal VLSI, Univ. of Macau, Macao, China
Abstract :
This paper presents an ultra-low-power capacitance-to-digital converter (CDC) for digital microfluidics systems that demand a wide capacitive sensing range. It is structured with a switched-capacitor capacitance-to-current front-end interface, followed by a differential current-mode SAR analog-to-digital converter (ADC). By using subthreshold-biased transistors, the differential current-mode SAR ADC significantly saves power and reduces sensitivity to supply voltage and clock variation. The 8-bit 1-kS/s CDC designed in 0.35-μm CMOS exhibits a capacitance sensing range from 1.5 to 20 pF while consuming a total power of 0.8 μW. The ENOB of the current SAR ADC is 7.46.
Keywords :
CMOS digital integrated circuits; analogue-digital conversion; biomedical electronics; capacitance measurement; lab-on-a-chip; microfluidics; ADC; CDC; CMOS design; ENOB; capacitance sensing; clock variation; differential current-mode SAR ADC; differential current-mode SAR analog-to-digital converter; input-range capacitance-to-digital converter; lab-on-chip digital microfluidics systems; power 0.8 muW; subthreshold-biased transistors; switched-capacitor capacitance-to-current front-end interface; total power; ultralow-power capacitance-to-digital converter; voltage supply; Capacitance; Capacitors; Electrodes; Microfluidics; Mirrors; Sensors; Transistors;
Conference_Titel :
Biomedical Circuits and Systems Conference (BioCAS), 2012 IEEE
Conference_Location :
Hsinchu
Print_ISBN :
978-1-4673-2291-1
Electronic_ISBN :
978-1-4673-2292-8
DOI :
10.1109/BioCAS.2012.6418416
