A 1.2V 1.3μW Cascode Current Reuse Based Neural Amplifier with 113 dB Open-Loop Gain

Abstract

One of the major challenges in the acquisition of neural signals is the design of electronic signal acquisition system. Specialized amplifier circuitry is required in the neural recording system to accurately extract information from weak neural signals. High gain, high input impedance amplifiers are part of such systems. This paper presents the design of a high gain modified casocde current reuse open loop amplifier suitable for such applications. The amplifier has a open loop gain of 113 dB, a bandwidth of 10 kHz and unity-gain bandwidth (UGB) of 6.6 MHz. Further, design and simulation of high gain and low power neural amplifier is presented which uses the proposed high gain modified cascode current reuse amplifier with capacitive feedback. The neural amplifier has a closed loop gain of 45.8 dB over 85 Hz - 8.2 kHz and consumes approximately 1.3 μW of power. The design and the simulation is done using the UMC 90nm CMOS process employing 1.2 V power supply. The small signal DC gain, bandwidth and power of the neural amplifier are found to be better than the previously published works. © 2023 IEEE.