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https://hdl.handle.net/10356/154553
Title: | An ultra-low-voltage VCO-based ΔΣ modulator using self-compensated current reference for variation tolerance | Authors: | Narasimman, Neelakantan Kim, Tony Tae-Hyoung |
Keywords: | Engineering::Electrical and electronic engineering | Issue Date: | 2021 | Source: | Narasimman, N. & Kim, T. T. (2021). An ultra-low-voltage VCO-based ΔΣ modulator using self-compensated current reference for variation tolerance. Circuits, Systems, and Signal Processing, 40, 1089-1110. https://dx.doi.org/10.1007/s00034-020-01523-6 | Project: | RG174/18 | Journal: | Circuits, Systems, and Signal Processing | Abstract: | This paper introduces a voltage-controlled-oscillator-based (VCO-based) first-order delta-sigma (ΔΣ) modulator that uses a novel current reference to improve the robustness of the modulator at ultra-low operating voltages. The proposed current reference harnesses the difference in transistor characteristics between weak inversion and moderate inversion to generate residue voltage, which is a function of process and temperature variations. The current generated by the proposed reference is used to bias a fully differential VCO integrator and a feedback current digital-to-analog conversion in the delta-sigma modulator for variation tolerance. Test chips designed and fabricated in 65-nm CMOS technology operate successfully at 0.3 V and achieve SNDR of 56.1 dB across 10 kHz bandwidth while consuming only 510 nW of power. This corresponds to a state-of-the-art figure of merit of 49 fJ/conv.-step. Measurement results for the proposed current reference and the modulator also demonstrate 3 × and 20 × improvement in process and temperature variation tolerance, respectively, while operating at such low voltages. | URI: | https://hdl.handle.net/10356/154553 | ISSN: | 0278-081X | DOI: | 10.1007/s00034-020-01523-6 | Schools: | School of Electrical and Electronic Engineering | Organisations: | A*STAR Institute of Microelectronics | Rights: | © Springer Science+Business Media, LLC, part of Springer Nature 2020. All rights reserved. | Fulltext Permission: | none | Fulltext Availability: | No Fulltext |
Appears in Collections: | EEE Journal Articles |
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