Title :
Broadband dielectric spectroscopy CMOS readout circuit for molecular sensing
Author :
Kim, Youngbok ; Agarwal, Anuj ; Sonkusale, S.R.
Author_Institution :
Dept. of Electr. Eng., Texas A&M Univ., College Station, TX, USA
Abstract :
The readout circuit of broadband dielectric spectroscopy (BDS) for molecular sensing is described. The circuit performs a high-precision capacitance-to-current conversion and amplification of the difference of signals generated by two very small capacitors in the conventional CMOS 0.18 μm technology. We make use of the continuous-time common mode error amplification and offset-cancelling low-noise lock-in architecture to measure the admittance as a function of frequency. The power consumption of the front-end is under 30 μW/channel. It has a quasi-linear conversion ratio of 164 pA/aF.
Keywords :
CMOS integrated circuits; capacitive sensors; chemical sensors; current-mode circuits; electric admittance measurement; permittivity measurement; readout electronics; 0.18 micron; 30 muW; BDS; CMOS readout circuit; OTA-C filter; admittance frequency dependence; admittance measurement; broadband dielectric spectroscopy; capacitive measuring techniques; capacitor generated signal difference amplification; chemical detector; common mode error amplifier; continuous-time common mode error amplification; current-mode ADC; dielectric permittivity measurement; high-precision capacitance-to-current conversion; low power capacitance sensor; low-pass filtering; mixer; molecular sensing; offset-canceling low-noise lock-in architecture; quasi-linear conversion ratio; voltage-current converter; Admittance measurement; CMOS technology; Capacitance; Capacitors; Circuits; Dielectrics; Electrochemical impedance spectroscopy; Energy consumption; Frequency measurement; Signal generators;
Conference_Titel :
Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on
Print_ISBN :
0-7803-8834-8
DOI :
10.1109/ISCAS.2005.1465983
