Mixed Signal Techniques for Analog-to-Digital Converter Design with Sub-Picosecond Time-Domain Performance in Nanometer CMOS

Worcester Polytechnic Institute, Worcester MA

Investigators

Abstract

MIXED SIGNAL TECHNIQUES FOR ANALOG-TO-DIGITAL CONVERTER DESIGN WITH SUB-PICOSECOND TIME-DOMAIN PERFORMANCE IN NANOMETER CMOS PROJECT ABSTRACT Intellectual Merit Low-cost high-performance analog-to-digital converters are required in many rapidly growing mixed-signal application areas such as ultrawideband wireless data standards, wireline serial data transmission, and high-density disk drives. To address needs in these areas, the objective of the proposed work is the design, test, and verification of low cost, high speed, energy efficient analog-to-digital converters operating at sample rates from 3 to 40 GSps and resolutions of 5-8 bits. Novel aspects of the proposed approach address difficulties in the area of analog-to-digital converter calibration and precision of sample clock timing. Calibration is addressed by extending a background digital correction technique developed by the principal investigator specifically tailored to the constraints of nanometer-scale digital integrated circuit technology. This correction technique has been extensively investigated by the principal investigator (and many others) as a promising approach in a diversity of higher resolution (12-16 bits), lower speed (1-100 MSps) architectures including cyclic, successive approx¬imation, pipeline, time-interleaved, and oversampling. In the proposed work, the technique will be applied for the first time to digital background calibration of flash analog-to-digital converters operating at speeds of 1 GSps and higher. Operating at these conversion rates requires that sample clock timing errors (jitter) be less than 1 picosecond. To address sample clock timing issues, the principal investigator?s previous work with fundamental limits on oscillator noise will be leveraged to enable low jitter high speed on-chip clock generation from a moderate cost, low frequency, commercial-off-the-shelf frequency reference. Broader Impacts Combining these techniques will result in a low-cost, high speed analog-to-digital conversion capability required for a wide range of emerging mixed-signal applications. In particular, achieving this capability in an energy-efficient manner will allow continued improvement in system functionality when low power consumption is critical; for example, in mobile and untethered applications. In addition to technical advances, the project will also contribute to the goal of expanding education by supporting a Ph.D. student to perform much of the research work. Every effort will be made to identify an individual from an underrepresented group when recruiting for this position. Research results will be integrated into classroom and project materials at both the graduate and undergraduate levels; this has proven to increase student engagement and interest in the field of mixed signal integrated circuit design. Finally, research materials at all levels of detail will be made available to the wider technical community through open access to design information.