A picoampere-sensitivity readout circuit for nanosensor array

This paper presents a picoampere-sensitivity readout integrated circuit (ROIC) based on capacitive transimpedance amplifier (CTIA) for hybrid nanosensor. The proposed ROIC utilizes CTIA structure to achieve stable sensor bias. Telescopic op-amp is employed to further minimize sensor bias variation according to theoretical analysis. A 32 × 32 readout circuit array is fabricated using 0.5 μm 2P3M CMOS technology to verify the design. Simulation and experiment results show that the proposed readout circuit can detect current as low as 4 pA while maintaining output linearity higher than 99.07% and bias variation lower than 0.013‰.