Looking for Good Waves: The Importance of Signal Integrity in High-Speed PCB Design

Edwin Robledo Edwin Robledo January 4, 2024

4 min read

Learn about the importance of signal integrity and how Autodesk Fusion helps to analyze PCB electromagnetic performance and ensure signal integrity.

In the world of Printed Circuit Board (PCB) design, signal integrity is a critical aspect that shapes the functionality and performance of the board. However, maintaining optimal signal integrity can be complex, especially with high-speed digital signals or high-frequency analog designs. This is where the Autodesk Fusion Signal Integrity Extension comes into play, offering a comprehensive solution to analyze PCB electromagnetic performance and ensure signal integrity. 

signal integrity

Understanding the Importance of Signal Integrity

Signal integrity (SI) plays a pivotal role in ensuring the efficient operation of a PCB. In essence, it refers to the ability of a signal to maintain its waveform characteristics from the source to the receiver without any degradation or distortion. It’s a measure of the quality of a signal, and a poor signal could lead to problems like signal loss, jitter, and crosstalk, drastically affecting the PCB’s performance. 

While all signals can benefit from maintaining signal integrity, it becomes a paramount concern when working with high-frequency or high-speed digital signals. In such scenarios, the PCB design must account for issues such as signal reflections, ground bounce, and crosstalk. 

Why SI is Vital for PCB Design

signal integrity electronics

Poor signal integrity can manifest in various forms in a PCB design. In extreme cases, it might lead to occasional performance glitches, data loss, or complete system failure. Hence, ensuring SI is not just about optimizing performance but preventing catastrophic failures in your electronic devices. 

The pursuit of maintaining SI requires a deep understanding of the various signal integrity issues that can arise in PCB design. These include electromagnetic interference (EMI), unintentional electromagnetic coupling (crosstalk), simultaneous switching noise (ground bounce), and impedance mismatch. Addressing these issues requires carefully considering the PCB’s design, from the board’s layout to the placement and routing of components. 

Leveraging the Fusion Signal Integrity Extension

Autodesk Fusion Signal Integrity Extension

To make SI analysis more manageable and intuitive, Autodesk has introduced the Fusion Signal Integrity Extension. This powerful tool enables users to analyze their PCB electromagnetic performance, offering a seamless solution for maintaining SI. 

Ansys, a leading provider of solutions for electromagnetic simulations, powers this extension. With the extension, designers can select signals of interest for quick on-demand analysis, allowing them to identify problematic signal paths and make necessary design updates. 

Key Features

The extension offers numerous features designed to empower engineers in their quest to maintain signal integrity. These include: 

Impedance Matching

This core feature enables users to manage and control the impedance for every transmission line throughout their board, ensuring a distortion-free and optimal high-speed performance design. 

Signal Insights

signal integrity insights

Signal insights allow users to analyze their design and inspect parameters that characterize high-speed signals, such as propagation delay, trace length, impedance, and coupling. 

On-Demand Analysis

on demand signal integrity analysis

The extension also provides on-demand analysis capabilities. Users can modify the layers stack composition, signal path width, or coupling spacing and re-run the simulation for immediate on-demand feedback analysis. This feature significantly enhances the design iteration process, allowing for rapid testing and optimization. 

User Selectable Target Signals

This feature allows users to select the most critical signals of interest within their board for fast analysis. This includes all the geometries adjacent to those signal paths, ensuring a comprehensive understanding of the signal’s performance. 

Virtual Prototyping

signal integrity virtual prototyping

The extension also provides virtual prototyping capabilities. It enables users to simulate their design impedance and coupling performances in the design phase and before manufacturing. This feature helps reduce physical prototyping and EMI/EMC testing and improve product reliability. 

The Power of Fusion in Maintaining SI

autodesk fusion signal integrity extension

The extension equips users with the tools they need to ensure the compliance and performance of their smart products, reduce development costs, and accelerate their time to market. It helps minimize costly PCB physical testing and board re-spins, giving users access to feedback on their design’s electromagnetic performance and reducing the length of project timelines. 

Moreover, the extension offers simple input parameters and configuration, allowing engineers to select signals of interest for quick on-demand analysis. Users can analyze their design and inspect parameters that characterize high-speed signals, such as propagation delay, trace length, impedance, and coupling. 

Signal Integrity and the Fusion Signal Integrity Extension – A Winning Combination

autodesk fusion signal integrity

Maintaining SI is an integral part of PCB design. The task has become even more complex and challenging with the advent of high-speed digital signals and high-frequency analog designs. However, with tools like the Autodesk Fusion, engineers now have the resources to manage this complexity effectively. 

The extension provides a comprehensive solution to analyze PCB electromagnetic performance, making maintaining signal integrity more manageable and intuitive. By leveraging this tool, designers can ensure that their designs not only meet the required performance standards but also comply with industry regulations and standards, ensuring the success of their PCB projects. 

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