A Sub-µW Reconfigurable Front-End for Invasive Neural Recording

Abstract

This paper presents a sub-µW ac-coupled reconfigurable front-end for the purpose of neural recording. The proposed topology embeds in it filtering capabilities allowing it to select among different frequency bands inside the neural signal spectrum. Power consumption is optimized by designing for bandwidth-specific noise targets that take into account the spectral characteristics of the input signal as well as the noise bandwidths of the noise generators in the circuit itself. An experimentally verified prototype designed in a 180 nm CMOS process draws a maximum of 815 nW from a 1 V source. The measured input-referred spot-noise at 500 Hz is ${\text{75}}\,{\text{nV}}/\sqrt {{\text{Hz}}} $ while the integrated noise in the 200 Hz - 5 kHz band is 4.1 µVrms.