A 6.5-μW 10-kHz BW 80.4-dB SNDR Gm-C-Based CT ∆∑ Modulator With a Feedback-Assisted Gm Linearization for Artifact-Tolerant Neural Recording
| Autor: | Jong Hyun Ahn, Yeowool Huh, Sanggeon Park, Taejune Jeon, Jejung Kim, Moon-Hyung Jang, Changuk Lee, Jeongsik Lim, Youngcheol Chae |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Dynamic range 020208 electrical & electronic engineering Linearity 02 engineering and technology Input impedance law.invention Voltage-controlled oscillator law Linearization Control theory Integrator 0202 electrical engineering electronic engineering information engineering Figure of merit Electrical and Electronic Engineering Resistor |
| Zdroj: | IEEE Journal of Solid-State Circuits. 55:2889-2901 |
| ISSN: | 1558-173X 0018-9200 |
| DOI: | 10.1109/jssc.2020.3018478 |
| Popis: | This article presents a Gm-C-based continuous-time delta–sigma modulator (CTDSM) for artifact-tolerant neural recording interfaces. We propose the feedback-assisted Gm linearization technique, which is applied to the first Gm-C integrator by using a resistive feedback digital-to-analog converter (DAC) in parallel to the degeneration resistor of the input Gm. This enables the input Gm to process the quantization noise, thereby improving the input range and linearity of the Gm-C-based CTDSM, significantly. An energy-efficient second-order loop filter is realized by using a voltage-controlled oscillator (VCO) as the second integrator and a phase quantizer. A proportional–integral (PI) transfer function is employed at the first integrator, which minimizes the output swing while maintaining loop stability. Fabricated in a 110-nm CMOS process, the prototype CTDSM achieves a high input impedance, 300-mVpp linear input range, 80.4-dB signal-to-noise and distortion ratio (SNDR), 81-dB dynamic range (DR), and 76-dB common-mode rejection ratio (CMRR) and consumes only 6.5 $\mu \text{W}$ with a signal bandwidth of 10 kHz. This corresponds to a figure of merit (FoM) of 172.3 dB, which is the state of the art among the neural recording ADCs. This work is also validated through the in vivo experiment. |
| Databáze: | OpenAIRE |
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