800 nW 43 nV/√Hz neural recording amplifier with enhanced noise efficiency factor

Advances in neuroscience research and clinical applications have increasingly called for the low-power low-noise simultaneous recording of neural signals from a large number of electrodes. The neural interface IC is one of the essential blocks to capture the weak neural signals. Presented is an energy-efficient low-noise neural recording amplifier with enhanced noise efficiency factor (NEF) for neural recording systems. Based on the conventional capacitive feedback and pseudo-resistor structure, the fully differential neural amplifier employs the current-reuse technique to achieve low noise and high current efficiency, consuming 800 nA at 1 V power supply. The measured thermal noise floor is 43nV/ √Hz and the input-referred noise is 5.71 V_rms when integrated from 1 Hz to 50 kHz, leading to an NEF of 2.59. The entire neural amplifier has been fabricated using a 0.18 m CMOS technology, occupying an area of 0.05 mm².