While not long ago systems had only several serial links, it’s now becoming common for systems to include hundreds – and even thousands – of such links. This paper describes the development and analysis of a large system with thousands of serial links. Due to the system’s size and complexity, the design team invested in a multi-year effort to build and qualify a virtual environment capable of both verifying connectivity and simulating any and all of the channels. Problematic channels with incomplete system-level connections, poor eye openings, or high BER are quickly identified. Performance limiters such as inherent discontinuities (and their associated resonances), and Tx/Rx equalization imbalance are found and examined in detail. The virtual system is also used to guide design choices such as layer stacking, via construction, back-drilling, and trace/connector impedances. Processes to optimize and select equalization choices are also described.
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Editorial
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DAC 2012 at San Francisco CA - Jun 3 - 7, 2012
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