A 0.13[mu]m CMOS 78dB SNDR 87mW 20MHz BW CT [Delta Sigma] ADC with VCO-based integrator and quantizer
Name
Park-2009-A 0.13m CMOS 78dB SNDR 87mW 20MHz BW CT ADC with VCO-based integrator and quantizer.pdf
Size
1.16 MB
Format
Adobe PDF
Checksum (MD5)
5acd1a999df47d3b601efbad16b4bf73
Author(s)
Park, Matthew
Alternative Title
A 0.13µm CMOS 78dB SNDR 87mW 20MHz BW CT ΔΣ ADC with VCO-based integrator and quantizer
Date Issued
May 2009
Journal
IEEE International Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009
Publisher
Institute of Electrical and Electronics Engineers
Citation
Park, M., and M. Perrott. “A 0.13[mu]m CMOS 78dB SNDR 87mW 20MHz BW CT [DeltaSigma] ADC with VCO-based integrator and quantizer.” Solid-State Circuits Conference - Digest of Technical Papers, 2009. ISSCC 2009. IEEE International. 2009. 170-171,171a. ©2009 IEEE.
Version
Final published version
Abstract
In this paper we demonstrate a new technique that eliminates the impact of K[subscript v] nonlinearity by preserving the integral relationship of the VCO output phase to the input signal. Leveraging the VCO output phase directly precludes the need to span the entire nonlinear K[subscript v] characteristic since small perturbations (in the range of 10s of mV) at the tuning node are sufficient to shift the VCO phase by a substantial amount. Since an open-loop VCO is sensitive to frequency offsets and drift, and easily saturates its phase detector for large input signals, some form of negative feedback is necessary. Here, a multibit DAC subtracts the previously quantized phase value from the VCO input, creating a residue that is integrated during the next clock cycle. This feedback loop not only allows large signals to drive the VCO without incurring distortion from K[subscript v] nonlinearity, but also it is a 1s,-order CT DeltaSigma ADC loop, and it therefore 1s,-order shapes quantization noise.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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DOI of Published Version
https://doi.org/10.1109/ISSCC.2009.4977362
