A 4-26 Gbaud Configurable Multi-Mode Non-Uniform EOM with Improved Twin PI for High-Speed Wireline Communication Achieving 3-μs EW/EH Evaluation and 0.99-R2 Accuracy

This paper presents a configurable multi-mode eye-opening monitor (EOM) with non-uniform sampling and quantization for on-chip high-speed link built-in-self-test (BIST). The EOM can operate in three modes, enabling it to not only capture the colored eye diagram but also rapidly outline its contour, eye height (EH), and eye width (EW). In the non-uniform-scanning mode (NSM), the EH and EW are swiftly measured using an optimization algorithm to adjust the control codes of a 7-bit twin phase interpolator (PI) and a 6-bit R-2R digital-to-analog converter (DAC). In the fast-multi-sampling mode (FMSM), the reduced number of sampled error bits in each pixel facilitates a prompt generation of the eye contour. The EOM can also reconstruct the eye diagram in the multi-sampling mode (MSM) by analyzing the probability density function (PDF) of a 128×63 pixel array. Fabricated in 28-nm CMOS technology, the EOM can operate in 4-26 Gbaud within 0.005-mm
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area. At 26 Gbaud, it consumes 14.55 mW with 0.99-R
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accuracy and takes up 933 μs in the MSM, 597 μs in the FMSM, and ~3 μs in the NSM, respectively.