A highly linear DPOTA-based configurable analog front-end for EXG (EEG, ECG, and EMG)

Abstract

This paper presents a digitally controllable analog front-end (AFE) for a portable EEG, ECG, and EMG detection systems. It consists of a low-pass filter (LPF) and two programmable gain amplifiers (PGAs). The proposed AFE is based on a highly linear digitally programmable fully differential operational transconductance amplifiers (DPOTAs). The transconductance of the DPOTA can be controlled, from 25 nA/V to 400 nA/V, by 4-bit digital word. The proposed AFE is designed and simulated in 90 nm CMOS technology. The LPF cutoff frequency can be adjusted to 107 Hz, 257 Hz and 537 Hz which is suitable for EEG, ECG, and EMG, respectively. The gain of the PGA is tuned from 0 dB to 70 dB with 5 dB steps.