An Abstract of the Thesis of Title: Low Noise Clocking for High Speed Serial Links. Low Noise Clocking for High Speed Serial Links among Others I'm Forgetting, I Appreciate the Help of Ferne Simendinger, Clara

approvedAs the functionality of digital chips continues to increase dramatically, chipto-chip communication bandwidths must scale accordingly to avoid constraining the overall system performance. Therefore, high speed transceiver design has become an important research topic. In particular, the performance of the circuits that are responsible for timing accuracy are important as bit periods continue to shrink. Furthermore, in order for these circuits to have a true impact on the performance of the system, they must use unique architectures to achieve timing accuracy rather than simply trading power consumption for performance. This thesis discusses issues related to the timing circuits on both the transmit and receive side of the link. On the transmit side, a phase-locked loop (PLL) is used to generate the clock that tells the driver when to start and stop driving the current bit onto the channel. On the receive side, a clock and data recovery (CDR) circuit is responsible for properly centering the sampling clock in the middle of the bit period. Design techniques to achieve good timing performance in both the PLL and CDR are proposed. Specifically, the PLL incorporates a supply regulated tuning scheme to combat the high levels of supply noise present in large digital chips and a resistor-based charge pump to reduce the charge pump flicker noise contribution. The CDR uses oversampling to decouple the tradeoff between two important performance metrics: jitter generation and jitter tolerance. To validate the proposed ideas, both a PLL test chip and a CDR test chip are presented. The PLL operates from 0.5GHz to 2.5GHz and achieves 2.36ps rms jitter using a ring voltage-controlled oscillator. The power consumption scales favorably with frequency, using much less power at lower frequencies where less power is needed. The CDR operates up to 3.6Gbps with a BER of less than 10-12. The measured jitter tolerance corner frequency was improved by a factor of 30 from 1MHz to 30MHz without increasing the recovered clock jitter. ©Copyright by Merrick Brownlee November 10, 2006 All Rights Reserved Low Noise Clocking for High Speed Serial Links by Merrick Brownlee A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented November 10, 2006 Commencement June 2007 Doctor of Philosophy thesis of Merrick Brownlee presented on November 10, 2006.