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Reducing various types of noise such as reflections, mode-conversion, return-path bounce, and crosstalk becomes a serious challenge in signal integrity designs of high data-rate interfaces. In this article, Dror Haviv focuses on the analysis and properties of the FEXT, presenting an alternative way to analyze the FEXT and its properties using the superposition theory of the differential signal and the common signal.

Semiconductor signal conditioning and signal recovery innovations have extended data rates by managing allowable signal-to-noise ratio (SNR) at progressively higher Nyquist frequencies. We have experienced how each successive signaling technology increases the electro-mechanical design resolution needed to address the channel physics while respecting the SNR of the chips. These movements throughout the years have provided a baseline of traditional design goals that lead us to better understand today’s 224 Gbps-PAM4 physical layer requirements.

In this article, Cathy Liu discusses how channel error models and FEC performance analysis have been updated according to industry changes, as well as how different Ethernet coding schemes have been studied and simulated for 800GE and 1.6GE systems with 200 Gbps per lane. Liu investigates concatenated FEC with soft-decision decoding for inner code to protect 200 Gbps optical link and the effect of different FEC options on system SI.

As voltage margins for power rails continue to decrease, end-to-end power integrity modeling is already difficult without having to be concerned if all of your simulation models are correct. System designers typically assume that all of the vendor models are correct. So, what does an engineer do if one of the ASIC die models needed for a power integrity simulation is incorrect? 

DesignCon, the premier high-speed communications and system design conference, returns to its home at the Santa Clara Convention Center in Santa Clara, Calif., with technical paper sessions, tutorials, industry panels, product demos, and exhibits, January 30 to February 1, 2024. Group Event Director Suzanne Deffree reflects on the resources, networking, and innovation that DesignCon 2024 will bring.

In the final installment of his article series "DDR5 Electrical and Timing Measurement Techniques," Randy White explores how following a standard workflow for setting up thresholds and timings to distinguish bursts in DDR5 memory interfaces can make design validation much more efficient, ultimately ensuring compliance with specifications and improving system margin by identifying and resolving any issues, especially those related to either read or write transactions.

This paper addresses the challenge of how to simulate the power integrity ecosystem and include the feedback loop and switching noise of a switch mode power supply (SMPS) without waiting days for the simulation results. The solution presented here uses control loop theory state space equations to create a behavioral model of an SMPS that allows for fast simulation.

In this article, Randy White discusses variations in clock timing and how this can impact the reliability of a memory system. White highlights the importance of considering probe calibration, random jitter removal, and controlling bandwidth for accurate measurements, providing examples that demonstrate why care must be taken during probe attachment, calibration, and using a jitter/noise analysis application to evaluate jitter levels, therefore ensuring memory reliability.

Optimizing DDR5 memory system validation involves a strategic focus on probe and interposer solutions for in-system measurements. The selection of probe architecture, whether RC or RCRC, plays a key role in managing probe loading. To make the right choice, evaluating source impedance and signal characteristics, especially for bursted signaling, is essential. As DDR5 continues to evolve at higher speeds and reach its top speed phase, integrating non-ideal loading modeling within simulations and effectively de-embedding probe and interposer effects become critical components of a comprehensive testing plan.s