A DC-Coupled Neural Recording Analog Front-End with Bi-Level Bulk Modulation-Based EDO Compensation in 40nm Bulk CMOS
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Author
Diez-Clos, Arnau
Huang, Xiaohua
Monna, Bert
Muratore, Dante G.
DOI
10.1109/ISCAS56072.2025.11044232
Abstract
This paper presents a compact, low-power analog front-end (AFE) for high-density micro-electrocorticography (μECoG) recordings. The AFE integrates a DC-coupled, chopper-stabilized low-noise boxcar sampler, a passive switched-capacitor low-pass filter, and a 10-bit single-slope analog-to-digital converter (ADC). The boxcar sampler minimizes noise folding, enhances anti-aliasing and reduces chopping ripple. To prevent AFE saturation, a novel electrode DC offset (EDO) compensation loop is introduced. It features an embedded digital-to-analog converter (DAC) by modulating the bulk terminals of the input transistors, and a bi-level compensation scheme, thereby eliminating the requirements for high-resolution digital low-pass filters and explicit DACs typically used in traditional DC servo loops. Simulation results in 40nm bulk CMOS show an input-referred noise of 1.69 μVrms over a 1-500 Hz bandwidth, an EDO compensation range of 110 mVpp, with a power consumption of 2.28 μW and an estimated area of 0.0028 mm2 per channel
Publication Reference
A. Diez-Clos, X. Huang, B. Monna and D. G. Muratore, "A DC-Coupled Neural Recording Analog Front-End with Bi-Level Bulk Modulation-Based EDO Compensation in 40nm Bulk CMOS," 2025 IEEE International Symposium on Circuits and Systems (ISCAS), London, United Kingdom, 2025, pp. 1-5, doi: 10.1109/ISCAS56072.2025.11044232. keywords: {Electrodes;Technological innovation;Simulation;Noise;Low-pass filters;Channel estimation;Switches;Recording;Transistors;Servomotors;Neural recording;analog front-end (AFE);micro-electrocorticography (μECoG);chopper stabilization;bilevel compensation (BLC);bulk modulation;electrode DC offset (EDO)},
Year
2025