A Compact Operational Amplifier with Load-Insensitive Stability Compensation for High-Precision Transducer Interface
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sensors-18-00393-v2.pdf
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Author(s)
Yu, Zhanghao
Yang, Xi
Chung, SungWon
Date Issued
January 2018
Journal
Sensors
Publisher
Multidisciplinary Digital Publishing Institute (MDPI)
Citation
Yu, Zhanghao et al. "A Compact Operational Amplifier with Load-Insensitive Stability Compensation for High-Precision Transducer Interface." Sensors 18, 2 (January 2018): 393 © 2018 The Authors
Version
Final published version
Abstract
High-resolution electronic interface circuits for transducers with nonlinear capacitive impedance need an operational amplifier, which is stable for a wide range of load capacitance. Such operational amplifier in a conventional design requires a large area for compensation capacitors, increasing costs and limiting applications. In order to address this problem, we present a gain-boosted two-stage operational amplifier, whose frequency response compensation capacitor size is insensitive to the load capacitance and also orders of magnitude smaller compared to the conventional Miller-compensation capacitor that often dominates chip area. By exploiting pole-zero cancellation between a gain-boosting stage and the main amplifier stage, the compensation capacitor of the proposed operational amplifier becomes less dependent of load capacitance, so that it can also operate with a wide range of load capacitance. A prototype operational amplifier designed in 0.13-μ m complementary metal–oxide–semiconductor (CMOS) with a 400-fF compensation capacitor occupies 900-μ m² chip area and achieves 0.022–2.78-MHz unity gain bandwidth and over 65°phase margin with a load capacitance of 0.1–15 nF. The prototype amplifier consumes 7.6 μW from a single 1.0-V supply. For a given compensation capacitor size and a chip area, the prototype design demonstrates the best reported performance trade-off on unity gain bandwidth, maximum stable load capacitance, and power consumption. Keywords: analog integrated circuits; operational amplifiers; transducer interface circuit; Internet of Things (IoT) device
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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DOI of Published Version
https://doi.org/10.3390/s18020393
