0.3-V Nanopower Biopotential Low-Pass Filter

This paper presents a compact power-efficient CMOS fourth-order low-pass filter suitable for electrocardiogram (ECG) acquisition systems. The CMOS structure of the proposed filter utilize the bulk-driven technique and operates in subthreshold region to achieve extremely low-voltage supply (0.3V) and nanopower consumption (0.676 nW) for cut-off frequency of 100 Hz. The filter was designed and simulated using <inline-formula> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> CMOS TSMC technology. The total input referred noise of the filter is <inline-formula> <tex-math notation="LaTeX">$87~\mu $ </tex-math></inline-formula>Vrms and the dynamic range is 58.1 dB. The filter offers the best figure of merit of <inline-formula> <tex-math notation="LaTeX">$2.91\times 10^{-14}$ </tex-math></inline-formula> J, the lowest power consumption and voltage supply, compared with the previous state-of-the-art nanowatt filter designs.