Teardrops Tips & Tricks in Altium Designer

Summary

In this video, Zach Peterson from Altium Academy explains how to add teardrops in Altium Designer to improve the reliability of PCB designs. He discusses the importance of teardrops, particularly for vias and high-reliability products, as well as different methods of applying them, including curved and line styles. Zach also provides tips for ensuring proper copper connection to avoid design rule violations and improve the durability of electrical connections in high-vibration or thermally cycled environments. He walks through examples and highlights the importance of running design rule checks after applying teardrops.

Takeaways

• 🛠️ Teardrops in PCB design enhance reliability, especially in high-density interconnects.
• 💡 Teardrops are applied at pad-via connections to ensure sufficient copper coverage even if the drill misses the pad center.
• 🔧 Altium Designer has a built-in tool for adding teardrops, which can be customized for selected objects or applied universally.
• ⚠️ Adding teardrops may cause design rule violations (DRC), so running a design rule check afterward is crucial.
• 🔄 There are two styles of teardrops: curved and line. The speaker prefers the line style for better copper coverage on traces.
• 📏 Teardrop size is adjustable, but should be large enough to account for potential drill misalignment and ensure electrical reliability.
• 🚨 Teardrops should be applied where tracks widen, but the speaker has rarely been asked to use them on T-junctions.
• 🔄 You can remove, copy, or paste teardrops between objects in Altium Designer for flexibility during the design process.
• 🧑‍🏭 The speaker advises consulting with fabricators when using teardrops in high-reliability PCB designs.
• 📊 Teardrops are especially useful in high-vibration environments and with frequent thermal cycling, improving long-term board reliability.

Q & A

What is the purpose of teardrops in PCB design?

Teardrops in PCB design enhance reliability by increasing the connection area between vias, pads, and traces. They help maintain electrical connections even if there is misalignment during manufacturing or mechanical stress like vibration or thermal cycling.

Why are larger vias and pads preferred in PCB design?

Larger vias and pads are preferred because they provide greater mechanical and electrical stability. A bigger via allows more room for the drill to wander without severing the copper connection, improving the reliability of the PCB.

In what scenarios might a smaller via be necessary?

A smaller via might be necessary in high-density PCB designs where space is limited due to tight interconnects. When larger vias can't fit, teardrops can improve the reliability of smaller vias.

What should a designer do after adding teardrops to a PCB design?

After adding teardrops, the designer should run a Design Rule Check (DRC) to ensure that no violations, such as clearance errors, have been introduced. This is crucial as teardrops can sometimes lead to issues like shorts if they interfere with nearby copper or traces.

What is the benefit of using the line style teardrop over the curved style?

The line style teardrop is often preferred because it provides more copper coverage, especially along the trace, enhancing the mechanical and electrical stability of the connection.

How can a designer apply teardrops to specific objects in Altium Designer?

In Altium Designer, teardrops can be applied selectively by choosing 'Selected' in the Teardrops tool. This allows the designer to apply teardrops only to specific vias, pads, or tracks instead of applying them to the entire design.

What should a designer consider when determining the size of a teardrop?

The size of the teardrop should account for potential drill misalignment during manufacturing. The teardrop should be large enough to maintain an annular ring of copper around the via or pad, ensuring a reliable electrical connection even if the drill hits near the edge.

Can teardrops cause design rule violations, and how can they be addressed?

Yes, teardrops can cause DRC violations, especially in areas with nearby copper or traces. Designers can force the tool to add teardrops despite violations but should run a DRC afterward to identify and correct clearance errors.

What is the advantage of manually adjusting teardrop sizes in high-reliability designs?

Manually adjusting teardrop sizes allows designers to ensure optimal copper coverage for high-reliability connections, especially in cases where more mechanical or electrical stress is expected. Stretching the teardrop can create a wider and stronger connection.

Why is it important to consult with the fabricator when using teardrops?

Consulting with the fabricator is important because they can provide insights on manufacturability and any specific limitations that might affect the use of teardrops. This ensures that the design is not only reliable but also feasible to produce.