The Design of 8-Channel CMOS Area-Efficient Low-Power Current-Mode Analog Front-End Amplifier for EEG Signal Recording

In this paper, an 8-channel area-efficient low-power current-mode analog front-end amplifier (AFEA) is designed for EEG signal recording. The AFEA is composed of eight capacitive coupled transconductors (CCGMs), current-mode band-pass filters (CMBPFs), and programmable current-gain amplifiers (PCGAs) with a multiplexer (MUX), a transimpedance amplifier (TIA), and an offset current cancellation loop (OCCL). The AFEA employs CCGM with only 2pF input capacitance to eliminate the electrode dc offset (EDO). The current-mode topology is adopted in the design of CCGMs, CMBPFs, and PCGAs to reduce the power consumption. The shared OCCL is designed to eliminate the output offset of CCGM, CMBPF and PCGA. The AFEA is designed and fabricated in 180-nm CMOS technology and the core area occupies only 1mm(2). The measured maximum gain is 82 dB. The measured input-referred noise is 3.34 mu V-rms within the bandwidth of 0.5-100 Hz. The measured maximum power consumption is 7.85 mu W per channel under power supply of 1.2V. The fabricated AFEA is applied to record the human EEG signal successfully.