Title :
A CMOS detector system for fluorescent bio-sensing application
Author :
Liu, Nan ; Hong, Zhiliang ; Liu, Ran
Author_Institution :
State Key Lab. of ASIC & Syst., Fudan Univ., Shanghai
Abstract :
This system integrates a CMOS process compatible photodiode, a low noise capacitive trans-impedance amplifier (CTIA) and a 12-bit pipelined analog-to-digital converter (ADC). The chip fabricated in a 0.18-mum standard CMOS technology occupies 3 MMZ and consumes 37 mW. Experimental results show that the Nwell/Psub photodiode used in the fluorescent detecting experiment has a sensitivity of 0.1 A/W at 515 nm and a dark current of 3 nA/cm2. The maximum differential and integral nonlinearity of the designed ADC are +0.8 LSB and -3 LSB, respectively. With a solution volume of 0.5 mul, the detector system is able to detect the fluorescein solution concentration as low as 625 ng/ml. The minimum detectable fluorescent intensity and photocurrent are 18 nW/cm2 and 36 fA, respectively.
Keywords :
CMOS integrated circuits; analogue-digital conversion; biosensors; dark conductivity; fluorescence; low noise amplifiers; photodiodes; photoemission; 12-bit pipelined analog-to-digital converter; CMOS detector system; CMOS process compatible photodiode; current 36 fA; dark current; fluorescein solution concentration; fluorescent bio-sensing application; fluorescent intensity; low noise capacitive transimpedance amplifier; photocurrent; photodiode sensitivity; power 37 mW; size 0.18 mum; wavelength 515 nm; CMOS process; CMOS technology; Circuits; Dark current; Detectors; Fluorescence; Object detection; Photodiodes; Switches; Voltage;
Conference_Titel :
Solid-State Circuits Conference, 2008. A-SSCC '08. IEEE Asian
Conference_Location :
Fukuoka
Print_ISBN :
978-1-4244-2604-1
Electronic_ISBN :
978-1-4244-2605-8
DOI :
10.1109/ASSCC.2008.4708795
