A Configurable Multimode Nonuniform Eye-Opening Monitor for High-Speed Wireline Communication Achieving 3-μs EW/EH Evaluation and 0.98-R² Accuracy

Abstract

This article presents a configurable multimode eye-opening monitor (EOM) with nonuniform sampling and quantization for an on-chip high-speed link built-in self-test (BIST). The EOM can operate in three modes, enabling it to not only capture the color-graded eye diagram but also rapidly outline its contour, eye height (EH), and eye width (EW). In the nonuniform scanning mode (NSM), the EH and EW are swiftly measured using an optimization algorithm to adjust the control codes of a phase interpolator (PI) and a digital-to-analog converter (DAC). In the fast-multisampling mode (FMSM), the reduced number of samples in each pixel facilitates a prompt generation of the eye contour. The EOM can also reconstruct the eye diagram in the multisampling mode (MSM) by analyzing the probability density function (PDF) of a $128\times 63$ pixel array. Fabricated in a 28-nm CMOS technology, the EOM can operate up to 26 Gb/s within 0.005-mm2 area. At 26 Gb/s, it consumes 14.55 mW with more than 0.98- $R^{2}$ accuracy and takes up $933~\mu $ s in the MSM, $597~\mu $ s in the FMSM, and $\sim 3~\mu $ s in the NSM, respectively.