altium designer 17 preview track glossing

 

Introduction

Altium Designer 17 is a powerful electronic design automation (EDA) software that offers a comprehensive suite of tools for printed circuit board (PCB) design, simulation, and manufacturing. One of the key features of Altium Designer is its ability to perform track glossing, which is a process that smooths out the corners and edges of tracks (copper traces) on a PCB layout. This feature is particularly important for high-frequency and high-speed designs, as it helps to minimize signal reflections and ensure signal integrity.

In this article, we will explore the concept of track glossing in Altium Designer 17, its benefits, and how to effectively utilize this feature in your PCB designs.

What is Track Glossing?

Track glossing, also known as track chamfering or track cornering, is a technique used in PCB design to smooth out the sharp corners and edges of copper tracks. These sharp corners and edges can act as sources of signal reflections, which can degrade signal quality, especially in high-frequency and high-speed applications.

When a signal travels along a copper track, it encounters impedance discontinuities at sharp corners and edges. These discontinuities can cause the signal to reflect back, creating signal reflections and ringing. These reflections can lead to signal integrity issues, such as electromagnetic interference (EMI), crosstalk, and timing violations, which can ultimately affect the performance and reliability of the electronic system.

By smoothing out the corners and edges of the copper tracks, track glossing reduces the impedance discontinuities and minimizes signal reflections. This results in better signal integrity and improved overall performance of the PCB design.

Benefits of Track Glossing

Track glossing offers several benefits for PCB designs, particularly in high-frequency and high-speed applications. Here are some of the key advantages:

1. Improved Signal Integrity: By reducing signal reflections and minimizing impedance discontinuities, track glossing helps maintain signal integrity, ensuring reliable data transmission and minimizing signal degradation.
2. Better EMI Performance: Sharp corners and edges on copper tracks can act as sources of electromagnetic radiation, contributing to EMI issues. Track glossing reduces these sharp transitions, thereby improving the EMI performance of the PCB design.
3. Enhanced High-Speed Design Performance: In high-speed designs, signal integrity is crucial for ensuring proper timing and functionality. Track glossing helps to maintain signal quality, enabling better performance in high-speed applications.
4. Increased Design Margins: By optimizing signal integrity and reducing reflections, track glossing provides additional design margins, allowing for higher operating frequencies or longer trace lengths without compromising performance.
5. Simplified Design Verification: With reduced signal reflections and improved signal integrity, design verification becomes more straightforward, as fewer issues related to signal quality need to be addressed.

Implementing Track Glossing in Altium Designer 17

Altium Designer 17 provides a dedicated feature for track glossing, which allows you to define the parameters for smoothing the corners and edges of copper tracks. Here's how you can implement track glossing in your PCB designs:

1. Open your PCB design in Altium Designer 17.
2. Access the Track Glossing settings: Go to the "Design" menu, and select "Rules". In the Rules dialog box, navigate to the "PCB Editor" section, and then choose "Track Glossing".
3. Configure the Track Glossing settings: In the Track Glossing dialog box, you can adjust various parameters to control the smoothing of track corners and edges. These parameters include:
   • Gloss Type: Choose whether to apply glossing to all tracks, or only to tracks with specific width or layer settings.
   • Gloss Radius: Specify the radius of the arc used to smooth the track corners and edges. A larger radius results in more rounded corners, while a smaller radius produces a tighter smoothing effect.
   • Maximum Angle: Set the maximum angle (in degrees) at which glossing will be applied. Corners with angles larger than this value will not be glossed.
   • Minimum Length: Define the minimum length (in millimeters or mils) of the track segment that will be glossed. This helps prevent excessive smoothing of very short track segments.
4. Apply the Track Glossing settings: After configuring the desired settings, click "OK" to apply the track glossing rules to your PCB design.
5. Verify the results: Use the 3D viewer or the PCB panel in Altium Designer to inspect the glossed tracks and ensure that the smoothing effect meets your requirements.

It's important to note that excessive track glossing can lead to increased copper area and potential clearance violations. Therefore, it's recommended to strike a balance between signal integrity and design constraints, such as component placement and routing density.

Considerations and Best Practices

While track glossing can significantly improve signal integrity and performance in high-frequency and high-speed PCB designs, there are several considerations and best practices to keep in mind:

1. Design Rules: Ensure that your track glossing settings comply with your design rules and manufacturing guidelines. Excessive glossing can lead to violations of clearance requirements or copper area limits.
2. Component Placement: Track glossing can impact the routing density and available space for component placement. Consider the effects of glossing on your component placement strategy and adjust accordingly.
3. Differential Pair Routing: When working with differential pairs, it's important to ensure that both tracks in the pair are glossed consistently to maintain balanced impedance and minimize skew.
4. Simulation and Verification: Whenever possible, perform simulations and verification of your PCB design with track glossing applied. This will help identify any potential issues related to signal integrity, EMI, or other performance factors.
5. Manufacturing Constraints: Consult with your PCB manufacturer to understand their capabilities and limitations regarding track glossing. Some manufacturers may have specific guidelines or restrictions on the extent of glossing they can accommodate.
6. Consistent Application: Apply track glossing consistently throughout your PCB design to ensure uniform signal integrity and performance across the entire system.
7. Design Cycle Considerations: Implement track glossing early in the design cycle to avoid rework and minimize the impact on other design aspects, such as component placement and routing.

By following these considerations and best practices, you can effectively leverage the track glossing feature in Altium Designer 17 to improve signal integrity and overall performance in your PCB designs.

FAQs

1. What is the difference between track glossing and track chamfering? Track glossing and track chamfering are essentially the same process, referring to the smoothing of sharp corners and edges on copper tracks. The terms are often used interchangeably.
2. Can track glossing be applied selectively to specific tracks or layers? Yes, Altium Designer 17 allows you to configure track glossing rules based on track width, layer, or other criteria. This enables selective application of glossing to specific tracks or layers in your PCB design.
3. How does track glossing affect impedance control? Track glossing can have an impact on impedance control, as it alters the geometry of the copper tracks. However, the effect is generally minimal, especially if the glossing radius is kept relatively small. It's important to perform simulations and verify that the glossed tracks meet your impedance requirements.
4. Can excessive track glossing cause clearance violations? Yes, excessive track glossing can potentially lead to clearance violations, as the smoothed corners and edges may encroach upon the clearance areas of nearby components or tracks. It's essential to strike a balance between signal integrity and clearance requirements when configuring track glossing settings.
5. Is track glossing required for all high-speed PCB designs? While track glossing is highly recommended for high-frequency and high-speed PCB designs to maintain signal integrity, it may not be strictly required for all designs. The decision to apply track glossing should be based on factors such as operating frequencies, signal integrity requirements, and design constraints.

Conclusion

Track glossing is a valuable feature in Altium Designer 17 that helps improve signal integrity and overall performance in high-frequency and high-speed PCB designs. By smoothing out the sharp corners and edges of copper tracks, track glossing minimizes signal reflections and impedance discontinuities, resulting in better signal quality and reduced EMI.

While implementing track glossing, it's crucial to consider design rules, component placement, differential pair routing, and manufacturing constraints to ensure a balanced and optimal design. Additionally, consistent application of track glossing throughout the design and early implementation in the design cycle are recommended best practices.

By leveraging the track glossing feature in Altium Designer 17 and following the considerations and best practices outlined in this article, you can enhance the signal integrity and overall performance of your PCB designs, particularly in high-frequency and high-speed applications.