A compact neural amplifier with high input impedance

In this paper, we present a new compact, high-input-impedance amplifier for neural signal acquisition. In this design, current feedback is achieved in a modified fully differential folded cascode amplifier to isolate the input signal from the feedback connection and thus increase the input impedance of the preamplifier. Common mode feedback circuits and ponderous capacitors are eliminated by using this structure. A band-pass filter with configurable low-frequency roll-off is connected to the preamplifier to further condition the signal. The whole design achieves the merits of high impedance, compact, low power and low noise. Simulation results are provided in this paper.