University of Oulu

I. Nissinen, J. Nissinen, P. Keränen, D. Stoppa and J. Kostamovaara, "A 16 x 256 SPAD Line Detector With a 50-ps, 3-bit, 256-Channel Time-to-Digital Converter for Raman Spectroscopy," in IEEE Sensors Journal, vol. 18, no. 9, pp. 3789-3798, May1, 1 2018. doi: 10.1109/JSEN.2018.2813531

A 16×256 SPAD line detector with a 50-ps, 3-bit, 256-channel time-to-digital converter for Raman spectroscopy

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Author: Nissinen, Ilkka1; Nissinen, Jan1; Keränen, Pekka1;
Organizations: 1Circuits and Systems Research Unit, University of Oulu, 90014 Oulu, Finland
2Fondazione Bruno Kessler, 38123 Povo, Italy
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.3 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2018
Publish Date: 2018-05-16


A 16 × 256 element single-photon avalanche diode array with a 256-channel, 3-bit on-chip time-to-digital converter (TDC) has been developed for fluorescence-suppressed Raman spectroscopy. The circuit is fabricated in 0.35 μm high-voltage CMOS technology and it allows a measurement rate of 400 kframe/s. In order to be able to separate the Raman and fluorescence photons even in the presence of the unavoidable timing skew of the timing signals of the TDC, the time-of-arrival of every detected photon is recorded with high time resolution at each spectral point with respect to the emitted short and intensive laser pulse (~150 ps). The dynamic range of the TDC is set so that no Raman photon is lost due to the timing skew, and thus the complete time history of the detected photons is available at each spectral point. The resolution of the TDC was designed to be adjustable from 50 ps to 100 ps. The error caused by the timing skew and the residual variation in the resolution of the TDC along the spectral points is mitigated utilizing a calibration measurement from reference sample with known smooth fluorescence spectrum. As a proof of concept, the Raman spectrum of sesame seed oil, having a high fluorescence-to-Raman ratio and a short fluorescence lifetime of 1.9 ns, was successfully recorded.

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Series: IEEE sensors journal
ISSN: 1530-437X
ISSN-E: 1558-1748
ISSN-L: 1530-437X
Volume: 18
Issue: 9
Pages: 3789 - 3798
DOI: 10.1109/JSEN.2018.2813531
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
114 Physical sciences
Funding: This work was supported by the Academy of Finland, Centre of Excellence in Laser Scanning Research under Contract 307362, Contract 282405, and Contract 314404.
Academy of Finland Grant Number: 307362
Detailed Information: 307362 (Academy of Finland Funding decision)
282405 (Academy of Finland Funding decision)
314404 (Academy of Finland Funding decision)
Copyright information: This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see