An ultrasensitive CMOS magnetic biosensor array with correlated double counting noise suppression

摘要

This paper presents a scalable and ultrasensitiveudfrequency-shift magnetic biosensing array scheme. Theudtheoretical limit of the sensor noise floor is shown to beuddominated by the phase noise of the sensing oscillators. Toudincrease the sensitivity, a noise suppression technique, Correlated Double Counting (CDC), is proposed with no power overhead. As an implementation example, a 64-cell sensor array is designed in a standard 65nm CMOS process. The CDC scheme achieves an additional 6dB noise suppression. The magnetic sensing capability of the presented sensor is verified by detecting micron size magnetic particles with an SNR of 14.6dB for a single bead and an effective dynamic range of at least 74.5dB.