Design of the analog front-end for the Timepix3 and Smallpix hybrid pixel detectors in 130 nm CMOS technology

• Published in: Journal of instrumentation Vol. 9; no. 1; p. C01037
• Main Authors: Gaspari, M De, Alozy, J, Ballabriga, R, Campbell, M, Fröjdh, E, Idarraga, J, Kulis, S, Llopart, X, Poikela, T, Valerio, P, Wong, W
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: Chips; CMOS; Compensation; Discriminators; Front-end electronics for detector readout Electronic detector readout concepts (solid-state) Analogue electronic circuits Pixilated detectors and associated VLSI electronics; Instrumentation; Leakage current; Pixels; Polarity; Preamplifiers
• ISSN: 1748-0221; 1748-0221
• DOI: 10.1088/1748-0221/9/01/C01037

This paper describes a front-end for hybrid pixel readout chips, which was developed for the Timepix3 and Smallpix ASICs. The front-end contains a single-ended preamplifier with a structure for leakage current compensation which can handle both signal polarities, and a single-threshold discriminator with compensation for pixel-to-pixel mismatch. Preamplifier and discriminator are required to be fast, to allow a Time-Of-Arrival (TOA) measurement with a resolution of 1.56 ns. Time-Over-Threshold (TOT) is also measured; the monotonicity of TOT with respect to the input charge is greatly improved as compared to the previous Timepix chip. The analog area is only 55 mu m x 13.5 mu m. Timepix3 has already been fabricated and the first test results are also presented in this paper.