A CMOS fluorescent detector system for biological experiment is presented. This system integrates a CMOS compatible photodiode, a capacitive trans-impedance amplifier （CTIA）, and a 12 bit pipelined analog-to- digita...A CMOS fluorescent detector system for biological experiment is presented. This system integrates a CMOS compatible photodiode, a capacitive trans-impedance amplifier （CTIA）, and a 12 bit pipelined analog-to- digital converter （ADC）, and is implemented in a 0.18μm standard CMOS process. Some special techniques, such as a ＂contact imaging＂ detecting method, pseudo-differential architecture, dummy photodiodes, and a T-type reset switch, are adopted to achieve low-level sensing application. Experiment results show that the Nwell/Psub photodiode with CTIA pixel achieves a sensitivity of 0.1 A/W at 515 nm and a dark current of 300 fA with 300 mV reverse biased voltage. The maximum differential and integral nonlinearity of the designed ADC are 0.8 LSB and 3 LSB, respectively. With an integrating time of 50 ms, this system is sensitive to the fluorescence emitted by the fluorescein solution with concentration as low as 20 ng/mL and can generate 7 fA photocurrent. This chip occupies 3 mm^2 and consumes 37 mW.展开更多
基金supported by the Micro/Nanoelectronics Science and Technology Innovation Platform of Fudan University of China
文摘A CMOS fluorescent detector system for biological experiment is presented. This system integrates a CMOS compatible photodiode, a capacitive trans-impedance amplifier （CTIA）, and a 12 bit pipelined analog-to- digital converter （ADC）, and is implemented in a 0.18μm standard CMOS process. Some special techniques, such as a ＂contact imaging＂ detecting method, pseudo-differential architecture, dummy photodiodes, and a T-type reset switch, are adopted to achieve low-level sensing application. Experiment results show that the Nwell/Psub photodiode with CTIA pixel achieves a sensitivity of 0.1 A/W at 515 nm and a dark current of 300 fA with 300 mV reverse biased voltage. The maximum differential and integral nonlinearity of the designed ADC are 0.8 LSB and 3 LSB, respectively. With an integrating time of 50 ms, this system is sensitive to the fluorescence emitted by the fluorescein solution with concentration as low as 20 ng/mL and can generate 7 fA photocurrent. This chip occupies 3 mm^2 and consumes 37 mW.
