Altium Designer is a popular software tool used for designing printed circuit boards (PCBs). It offers a wide range of features and functionalities to assist designers in creating efficient and reliable PCB layouts. One important aspect of PCB design is the proper utilization of vias, which are essential for creating connections between different layers of the board. In this article, we will explore the process of using vias in Altium Designer and address common issues that may arise during their implementation.
When designing an adapter PCB or any other type of PCB using Altium Designer, it is crucial to understand the correct usage of vias to achieve the desired results. Vias serve as pathways for electrical signals and allow connections between different layers of a PCB. However, sometimes designers encounter unexpected issues such as unwanted spacing around the vias or crossover patterns that can affect the manufacturability of the board.
One common reason for the presence of unwanted spacing around vias is the incorrect assignment of the vias to the same net as the copper areas. This can result in the addition of isolation rings around the vias during the design process. To fix this problem, it is necessary to ensure that the vias are assigned to the same net as the copper areas. By doing so, the unwanted spacing can be eliminated, making the design suitable for manufacturing.
To check and modify the net assignment of vias in Altium Designer, follow these steps:
- Double-click on the component containing the vias.
- Locate the properties box and find the column displaying the Via type and feature.
- Verify that the vias are assigned to the same net as the copper areas. If not, change the net assignment accordingly.
In some cases, even after assigning the vias to the correct net, another issue may arise in the form of a crossover shape instead of the desired circular shape. This problem can be attributed to the settings related to thermal relief in the via properties box. Thermal relief refers to the practice of creating isolated thermal connections between the vias and copper planes to enhance heat dissipation. By default, thermal relief is enabled in Altium Designer, resulting in the crossover shape.
To resolve this issue, follow these steps:
- Open the via properties box.
- Look for a check box labeled "Thermal Relief" under the Via Stack section.
- Uncheck the Thermal Relief box to establish a solid connection for the via.
If the crossover shape persists despite the Thermal Relief box being unchecked, another technique worth considering is the use of stitching. Stitching involves connecting multiple vias together to create a continuous electrical path. By adding stitching to the net, the desired effect can often be achieved.
To utilize stitching in Altium Designer, follow these steps:
- Investigate the stitching option in the software.
- Look for a feature that allows the addition of stitching to the net.
- Apply the stitching feature to the affected net, which should resolve the issue.
However, it is important to note that stitching might not always provide the best solution. In certain cases, the desired effect may be attained in the 3D model but not in the 2D representation, as shown in pictures below. In such situations, an alternative approach is required.
To address the problem of the crossover pattern persisting in the 2D model, you can try the following steps:
- Navigate to Design > Rules > Plane > Polygon Connect Style > PolygonConnect.
- Set the Connect Style to "Direct Connect."
- This adjustment should result in the desired pattern for the via connections in the 2D model.
In some instances, resetting the thermal relief box might cause distortion to the via connections to the polygon in certain layers. If this occurs, simply redraw the polygon, and the problem should be resolved.
By following the steps and techniques outlined in this article, you can effectively use vias in Altium Designer to design PCBs. These strategies will help you overcome common issues such as unwanted spacing, crossover patterns, and distorted via connections. As with any PCB design process, it is important to continually explore and experiment with different techniques to optimize the performance and manufacturability of your designs.
See also resin vs copper vias in PCB design.
