Signal Integrity Challenges and Solutions for USB4 and TBT3 Protocols

Abstract

Signal Integrity analysis for an I/O forms an integral part of high-speed design. Complex routing on the package, board and passive components degrade the signal quality. End to End simulation using highly corelated IBIS AMI models including S parameter models are the need for the day for validating the link simulation. USB4 & TBT3 are the next-generation USB data specification that increases the bandwidth of the interface and allows other protocols to share the physical interface. Doubling the data rate for every generation 5Gbps - 10Gbps – 20Gbps also doubles the Nyquist frequency making frequency dependent insertion losses worse. In addition, increased capacitive coupling at higher frequencies adds more interference or noise to the signal, making the crosstalk worse than it was in USB3.0/1/2 channels. This paper provides the challenges & solutions for on-die & platform to meet the electrical compliance requirements of I/O and talks on generating IBIS-AMI (Algorithmic Modeling Interface) models for 20Gbps PHY with the system.