A low-noise CMOS front-end amplifier based on auto correction feedback for biomedical systems

A low-power low-noise CMOS front-end amplifier with high input impedance and high common mode rejection ratio (CMRR) is proposed in this paper, which is applied to biomedical electronics such as EEG, ECG and neural recording. By using capacitor-coupled topology, wide input common mode range and low power consumption is achieved. Chopping and auto correction feedback loop (ACFB) are employed simultaneously to reduce the low frequency noises and output ripples. The front-end amplifier has been implemented in 0.18μm process. Simulation results show that a DC gain of 117.47dB, a GBW of 1.12MHz and input impedance more than 80MΩ is achieved with a supply voltage of 1.8V and a load capacitor of 5pF. The equivalent input noise power spectrum density (PSD) is 50.56nV/√Hz around 100Hz.