A 0.3 V, 4th order low-pass OTA-C filter using bulk-driven technique for EEG applications

Low-pass-filter (LPF) is one of the most important building blocks for the effective implementation of any wearable/non-invasive biological system. This manuscript, presents an ultra-low-power, low-voltage bulk-driven (BD) 4th order LPF circuit targeted for the detection of Electroencephalography (EEG) signal. The proposed LPF circuit works in the sub-threshold region to achieve low-power and low-noise operation. The simulated results obtained for proposed LPF CMOS in 180 nm technology node demonstrates -0.10 dB of dc-gain, 52.71 dB of dynamic range of (DR), 92 µVrms of input-referred noise (IRN) and 100 Hz of bandwidth. The LPF consumes power of 0.81 nW at 0.3 V of low-supply voltage. Using the most reasonable and relevant figure of merit (FOM), the proposed LPF circuit outperforms other modern nano-power LPF circuits and is most suitable for EEG acquisition systems.