An Active Electrode for Vital Signal Acquisition With Accurately-Tunable Sub-Hz High-Pass-Corner Frequency and 164-mVₚₚ Linear-Input-Range

Abstract

An active electrode (AE) for vital signal acquisition with accurately-tunable Sub-Hz high-pass-corner frequency ( $f_{HP}$ ) has been proposed. Thanks to the proposed PVT-insensitive pseudo-resistor (PR) with embedded calibration circuit, the sub-Hz $f_{HP}$ of the AE can be accurately tuned by an external clock frequency. The AE is implemented in a standard 55nm CMOS process with a core area of 0.11 mm2. The post-layout simulation results show that up to 310 $\text{G}\Omega $ of the PR value can be achieved. Compared with the conventional PR, the variation of the calibrated PR value is reduced by 3 decades within a temperature range of 0 to 85°C under all process corners. Besides, the bootstrap technique improves the linear-input-range of the AE up to 164 mVpp, demonstrating its potential capability to be applied to recording vital signals merged with large artifacts.