Issue link: https://resources.pcb.cadence.com/i/1534337
Collapsing eye diagram of signal trace with too much signal attenuation As shown in the two images above, at high frequencies (typically 1 GHz and above) and with fast rise times, even minor layout oversights can lead to significant issues. Impedance mismatches can cause signal reflections and degradation. Crosstalk between densely packed traces can blur data signals, while improper power distribution can compromise device perfor- mance. These challenges apply not only to RF applications but also to high-speed digital interfaces like USB 3.2 (5-10 Gbps) and PCIe Gen 4 (16 GT/s). The risks are high, and the margin for error is razor-thin, often leading to prototypes that pass initial tests but fail in real-world conditions. Enter OrCAD X and Presto PCB Editor This guide offers a pathway through these high-speed challenges, leveraging OrCAD X and Presto PCB Editor as powerful allies in your design process. With constraint-driven design capabilities and comprehensive tools for managing signal integrity, power integrity, and EMI control, these tools allow you to develop reliable, high-performance circuits faster. In this guide, you will find step-by-step approaches for constraint management, transmission line setup, stack-up design, and post-layout verification. Designed with practicality in mind, each section provides hands-on guidance to help you transition from schematic to finished layout, avoiding costly issues in high-speed designs. Introduction to High-Speed PCB Design High-speed PCB design is a specialized field within electronics design that deals with circuits operating at higher frequencies and data rates. These high-speed signals, typically found in applications such as data processing, telecommunications, and consumer electronics, introduce unique challenges that go beyond traditional PCB design practices. What Defines High-Speed Design? In essence, high-speed designs are characterized by: f High Signal Frequencies: Signals often exceed frequencies of 50 MHz, where signal behavior diverges from standard low-frequency circuits. f Fast Signal Rise Times (<100 ps): Rapid changes in signal voltage or current lead to reflections, crosstalk, and EMI, making signal integrity a central focus. f High Data Transfer Rates: Designs with data rates above 1 Gbps (0.5 GHz), such as USB 3.0 or DDR interfaces, require careful management of impedance and trace lengths to maintain signal quality. 4 www.cadence.com OrCAD X High-Speed Digital Design Guide