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Design of 4-channel analog front-ends for neural signal acquisition

A 4-channel analog front-ends designed for neural signal acquisition is demonstrated in this paper. Each channel consists of a high input impedance, high gain, low noise and high linearity amplifier and a high precision Σ-Δ analog to digital convertor (ADC). The amplifier is realized with a capacitive feedback closed loop op-amp. Fabricated in 180nm CMOS process, the 4-channel system occupies 2.34mm2 while achieving a resolution of 0.9μV and the equivalent input-referred noise of 3.06μV according to the chip test results.