True N-Bit Calibration of Pipeline A/D Converters: Trends and Challenges

David J. Allstot, Jianjun Guo, Ward J. Helms, Waisiu Law, Charles T. Peach
Abstract:
The digital calibration algorithm for conventional 1-b/stage pipelined analog-to-digital converters introduced by Karanicolas et al. [1] occasionally leads to missing or non- monotonic digital codes. In this paper, we show that an extension of that algorithm to 1.5-b/stage architectures actually leads to more frequent code errors. We also describe two methods to improve A/D performance in the presence of non-linear operational amplifiers. The first method uses a calibration that assures monotonicity in the presence of arbitrary comparator offset voltages. The second method employs an input-dependent level-shifting stage to achieve high linearity.
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IMEKO-IWADC-2003-65.pdf
DOI:
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