Trend Investigation of Biopotential Recording Front-End Channels for Invasive and Non-Invasive Applications

This paper presents the trend of biopotential recording front-end channels developed from the 1970s to the 2020s while describing a basic background on the front-end channel design. Only the front-end channels that conduct electrical recording invasively and non-invasively are addressed. The front-end channels are investigated in terms of technology node, number of channels, supply voltage, noise efficiency factor, and power efficiency factor. Also, multi-faceted comparisons are made to figure out the correlation between these five categories. In each category, the design trend is presented over time, and related circuit techniques are discussed. While addressing the characteristics of circuit techniques used to improve the channel performance, what needs to be improved is also suggested.