Title :
A 96 dB SNDR current-mode continuous-time ΔΣ modulator for electrochemical sensor arrays
Author :
Laifi, Anouar ; Al Abaji, M. Adib ; Thewes, Roland
Author_Institution :
Fac. of Electr. Eng. & Comput. Sci., Berlin Inst. of Technol. (Tech. Univ. Berlin), Berlin, Germany
Abstract :
A low-voltage fully differential current-mode continuous time delta-sigma modulator is presented for application in electrochemical sensor arrays. Although a first order topology is realized by using a single differential integrator, second order noise shaping is achieved. A differential quantizer based on current controlled oscillators (CCOs) allows a current-mode implementation with high noise-immunity and low-voltage compatibility. Thanks to the differential design nonlinearity impact on circuit performance is kept low. Moreover, the typical clock-jitter sensitivity for continuous time modulators is addressed by a switched shaped-current feedback DAC. The modulator implemented in 180 nm standard CMOS technology consumes 28μW and achieves an SNDR of 95dB at a signal bandwidth of 10 kHz and an oversampling ratio of 256.
Keywords :
CMOS integrated circuits; delta-sigma modulation; electrochemical sensors; jitter; oscillators; CCO; CMOS technology; SNDR current mode continuous-time ΔΣ modulator; circuit performance; clock jitter sensitivity; current controlled oscillators; differential design nonlinearity impact; differential integrator; differential quantizer; electrochemical sensor arrays; noise immunity; second order noise shaping; size 180 nm; switched shaped-current feedback DAC; CMOS integrated circuits; Capacitance; Clocks; Electrodes; Modulation; Oscillators; Transistors; ADC; CCO-based quantizer; Delta Sigma modulator; continuous time; current mode; electrochemical detection; relaxation oscillator;
Conference_Titel :
Mixed Design of Integrated Circuits & Systems (MIXDES), 2015 22nd International Conference
Conference_Location :
Torun
Print_ISBN :
978-8-3635-7806-0
DOI :
10.1109/MIXDES.2015.7208518
