A 0.0014 mm2, 1.18 TO Segmented Duty-Cycled Resistor Replacing Pseudo-Resistor for Neural Recording Interface Circuits

Abstract

This paper proposes a segmented duty-cycled resistor (SDR) that replaces the pseudo-resistor for neural recording amplifiers. To the authors' best knowledge, the proposed design, for the first time, achieves higher than 1 TO resistance and a switching frequency above the signal bandwidth at the same time. Therefore, it eliminates in-band switching artifacts and output DC drift. The SDR achieves up to 1.18TO with only 6.5% temperature variation and 1.5% chip-to-chip variation among 10 samples. Hence it offers sufficiently low and stable cut-off frequencies for both action potential and local field potential recordings, while only occupying an area of 0.001375mm2.