Citation: |
Junyao Ji, Xinao Ji, Ziyu Zhou, Zhichao Dai, Xuhui Chen, Jie Zhang, Zheng Jiang, Hong Zhang. A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic[J]. Journal of Semiconductors, 2024, 45(6): 062201. doi: 10.1088/1674-4926/23120049
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J Y Ji, X A Ji, Z Y Zhou, Z C Dai, X H Chen, J Zhang, Z Jiang, and H Zhang, A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic[J]. J. Semicond., 2024, 45(6), 062201 doi: 10.1088/1674-4926/23120049
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A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic
DOI: 10.1088/1674-4926/23120049
More Information
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Abstract
This paper presents a 16-bit, 18-MSPS (million samples per second) flash-assisted successive-approximation-register (SAR) analog-to-digital converter (ADC) utilizing hybrid synchronous and asynchronous (HYSAS) timing control logic based on an on-chip delay-locked loop (DLL). The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter (CDAC) than the synchronous and asynchronous SAR ADC. Therefore, the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large extent. In addition, the foreground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter (FIR-BPF) based least-mean-square (LMS) algorithm in an off-chip FPGA (field programmable gate array). Fabricated in 40-nm CMOS process, the prototype ADC achieves 94.02-dB spurious-free dynamic range (SFDR), and 75.98-dB signal-to-noise-and-distortion ratio (SNDR) for a 2.88-MHz input under 18-MSPS sampling rate.-
Keywords:
- SAR ADC,
- control logic,
- reference ringing,
- DAC incomplete settling
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References
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