Radiation-Tolerant MASH Delta-Sigma Time-to-Digital Converters
Time-to-Digital Converters (TDCs) are key building blocks in time-based mixed-signal systems, used for the digitization of analog signals in time domain. A short survey on state-of-the-art TDCs is given. In order to realize a TDC with picoseconds time res
- PDF / 540,364 Bytes
- 21 Pages / 439.37 x 666.142 pts Page_size
- 4 Downloads / 152 Views
Radiation-Tolerant MASH Delta-Sigma Time-to-Digital Converters Ying Cao, Paul Leroux, Wouter De Cock, and Michiel Steyaert
Abstract Time-to-Digital Converters (TDCs) are key building blocks in time-based mixed-signal systems, used for the digitization of analog signals in time domain. A short survey on state-of-the-art TDCs is given. In order to realize a TDC with picoseconds time resolution as well as multi MGy gamma-dose radiation tolerance, a third-order time-domain DS TDC structure is proposed. The first prototyping TDC, implemented in 0.13 mm, consumes only 1.7 mW from a 1.2 V supply. It achieves a time resolution of 5.6 ps and an ENOB of 11 bits, when the oversampling ratio (OSR) is 250. The SNDR is mainly limited by the skew error introduced by the comparator delay, which can be mitigated by using a delay-line assisted calibration technique. It improves the ENOB of the TDC to 13 bits and achieves a wide input dynamic range of 100-ns. The TDC also exhibits enhanced radiation tolerance owing to the mismatch-insensitive nature of the DS structure. Even after a total dose of 3.4 MGy at a high dose rate of 30 kGy/h, the ENOB only drops by 1 bit and, for an OSR of 250, a 10.5 ps time resolution is still achieved.
Y. Cao (*) KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, Room 91.21, B-3001 Heverlee, Leuven, Belgium SCK CEN, Mol, Belgium e-mail: [email protected] P. Leroux KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, B-3001, Heverlee, Belgium K.H. Kempen, Geel, Belgium W. De Cock SCK CEN, Mol, Belgium M. Steyaert KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, Room 01.21, B-3001, Heverlee, Belgium A.H.M. van Roermund et al. (eds.), Nyquist AD Converters, Sensor Interfaces, 223 and Robustness: Advances in Analog Circuit Design, 2012, DOI 10.1007/978-1-4614-4587-6_12, # Springer Science+Business Media New York 2013
224
12.1
Y. Cao et al.
Introduction
Recently, high resolution time-to-digital converters (TDCs) have gained more and more interest due to their increasing implementation in digital PLLs, ADCs, jitter measurement and time-of-flight (TOF) rangefinders. Specifically, a laser TOF rangefinder which operates by measuring the flight time of a light pulse from a laser transmitter to the target and back to an optical detector, can be applied to many industrial purposes, e.g., positioning of vehicles, detecting particles in atmosphere, measuring level heights in radioactive environments, etc. The accuracy of a TOF rangefinder is mainly determined by the resolution of the TDC employed. Upcoming applications in nuclear fusion reactors like the International Thermonuclear Experimental Reactor (ITER), electronic components are required to stand for higher than 5 MGy total dose radiation level [1], where the threshold voltage, transconductance, and delay of a transistor undergo dramatic changes. In these cases, the high accuracy and robustness of the TDC need to be inherent to the design. Conventional TDCs were built based on the CMOS gate-delay-line structure [2], whose highest achievable resolution i
Data Loading...
