CMOS direct time interval measurement of long-lived luminescence lifetimes

• Published in: 2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society Vol. 2011; pp. 5 - 9
• Main Authors: Yao, Lei, Yung, Ka Yi, Cheung, Maurice C., Chodavarapu, Vamsy P., Bright, Frank V.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 01.01.2011
• Subjects: Arrays; Bandwidth; CMOS integrated circuits; Equipment Design; Equipment Failure Analysis; Luminescence; Luminescent Measurements - instrumentation; Molecular Probe Techniques - instrumentation; Optical sensors; Reproducibility of Results; Semiconductors; Sensitivity and Specificity
• ISBN: 9781424441211; 1424441218
• ISSN: 1094-687X; 1557-170X; 1558-4615
• DOI: 10.1109/IEMBS.2011.6089883

We describe a Complementary Metal-Oxide Semiconductor (CMOS) Direct Time Interval Measurement (DTIM) Integrated Circuit (IC) to detect the decay (fall) time of the luminescence emission when analyte-sensitive luminophores are excited with an optical pulse. The CMOS DTIM IC includes 14×14 phototransistor array, transimpedance amplifier, regulated gain amplifier, fall time detector, and time-to-digital convertor. We examined the DTIM system to measure the emission lifetime of oxygen-sensitive luminophores tris(4,7-diphenyl-1, 10-phenanthroline) ruthenium(II) ([Ru(dpp) 3 ] 2+ ) encapsulated in sol-gel derived xerogel thin-films. The DTIM system fabricated using TSMC 0.35μm process functions to detect lifetimes from 4μs to 14.4μs but can be tuned to detect longer lifetimes. The system provides 8-bit digital output proportional to lifetimes and consumes 4.5mW of power with 3.3V DC supply. The CMOS system provides a useful platform for the development of reliable, robust, and miniaturized optical chemical sensors.