A 0.3-µW,2.1-µVrms Neural Recording Chopper Amplifier with Low Noise DC-Servo-Loop

This paper presents a low noise and low power circuit for neural recording. A Capacitively-Coupled Chopper Instrumentation Amplifier (CCIA) with embedded DC feedback is proposed to reduce the noise of system. Implemented a continuous-time low-pass filter (LPF) at the output of the system and utilized bulk-feedback techniques to increase its output swing. Furthermore, the DC-block and Chopper-Capacitor-Chopper Integrator Based DC Servo Loop (C3IB-DSL) are combined to reduce the interferences. According to experiment, the circuit consumes only 0.3 µW at 1.2 V. In addition, the input-referred noise reached 2.1 µVrms and the noise efficiency factor (NEF) 3.6 at the same time. The proposed CCIA was simulated in a 180n CMOS process.