Title :
On the calibration of a SPAD-based 3D imager with in-pixel TDC using a time-gated technique
Author :
Vornicu, I. ; Carmona-Galan, R. ; Rodriguez-Vazquez, A.
Author_Institution :
Inst. of Microelectron. of Seville (IMSE-CNM), Univ. of Seville, Seville, Spain
Abstract :
The optical characterization of a CMOS 64×64 single-photon avalanche-diode (SPAD) array with in-pixel 11b time-to-digital converter (TDC) is presented. The overall full-width half-maximum (FWHM) of the detector ensemble SPAD plus TDC is 690ps. The sensor has been fabricated in a 0.18μm standard CMOS technology which features an average dark-count rate (DCR) of 42kHz at 1V excess voltage (Ve) and room temperature. The detector successfully uses its time-gating capability to mitigate this large amount of noise enabling the sensor for accurate time-of-flight (ToF) measurements. The effectiveness of the time-gating technique is experimentally demonstrated. According to measurements, a time window of 400ns is enough to ensure that the TDC is triggered by light rather than by spurious events.
Keywords :
CMOS integrated circuits; avalanche photodiodes; time-digital conversion; 3D imager; CMOS technology; DCR; FWHM; SPAD array; ToF measurement; calibration; complementary metal oxide semiconductor; dark count rate; full-width half-maximum; in-pixel TDC; optical characterization; single-photon avalanche-diode; size 0.18 mum; time 400 ns; time-gated technique; time-of-flight measurement; time-to-digital converter; voltage 1 V; Arrays; CMOS integrated circuits; Detectors; Noise; Photonics; Standards; Three-dimensional displays; 3D imager; single-photon avalanche diode; time gating; time-of-flight; time-to-digital converter;
Conference_Titel :
Circuits and Systems (ISCAS), 2015 IEEE International Symposium on
Conference_Location :
Lisbon
DOI :
10.1109/ISCAS.2015.7168830