Abstract
Abstract In recent years, bio-medical electronics have been developed rapidly, especially the application of portable bio-potential signal acquisition. The bio-potential signals most commonly used in medical diagnoses include EEG, ECG and EMG, etc. However, the recordings of these signals are inconvenient and uncomfortable for patients, because they need to be connected to a stationary and bulky instrument during the examination. Moreover, the bio-potential signals reflect the physiological status of patients. In order to acquire the physiological information from patients effectively, recording multi-point at the same time is important. Therefore, there are growing demands for small size and multi-channel bio-potential signal acquisition system to improve the patients’ quality of daily life. This article presents a programmable low-noise readout front-end suitable for Electroencephalogram (EEG) acquisition. The chip includes 8-channel fully-differential chopper instrumentation amplifiers each with a small Gm-C low-pass filter, a programmable gain amplifier. The chip is fabricated with the TSMC 90nm CMOS process. The analog readout front-end has simulated frequency response from 0.57 Hz to 213 Hz, programmable gain from 54.4 dB to 87.6 dB, integrated input-referred noise of 0.358μVrms within EEG bandwidth, a noise efficiency factor (NEF) of 2.43, a power efficiency factor (PEF) of 2.95. The overall system consumes 29.08 µW under 0.5-V supply.