UBC Theses and Dissertations
An embedded calibration technique for high-resolution flash time-to-digital converters Cicalo, James
As CMOS technology continues to advance, device dimensions will continue to decrease, thus enabling the creation of circuits which operate at increasingly greater frequencies. However, this Increase In operating frequency has resulted in a reduced tolerance for circuit timing uncertainties. Therefore, techniques capable of measuring the timing characteristics of multi-GHz signals are needed to help address the growing number of timing problems found in modem CMOS circuits. For cost and accuracy reasons, embedded time interval measurement techniques which offer picosecond measurement accuracies and millisecond test-times are required to overcome these challenges. The "sampling offset" based flash time-to-digital converter (SOTDC) is an embedded time interval measurement technique that has recently garnered much attention due to its attractive properties. These properties include sub-millisecond test times of multi-GHz signals, in addition to the potential for measurement accuracies in the order of picoseconds. However, the accuracy of an SOTDC is strongly dependent upon the capabilities of its calibration technique, and present SOTDC calibration techniques suffer from some very serious limitations. In fact, these limitations are so severe that present calibration techniques are impractical under realistic production test conditions. This thesis presents the design and analysis of a novel embedded SOTDC calibration technique. The proposed calibration technique offers the potential for both sub-picosecond calibration accuracies and sub-100 millisecond calibration times. However, the main contribution of this work concerns the suitability of the proposed technique with a realistic production test environment. The capabilities of the proposed calibration technique have been proven using both mathematical analysis and behavioural modelling simulations.
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