If you’ve worked with PCB design and fabrication for any length of time, you’ve probably run across some unforeseen difficulties. Misaligned holes are one of those issues that can cause your PCB’s tracks to get disconnected over time. During production, the PCB’s quality and stability can be improved by inserting teardrops. This essay will delve more into the topic of teardrops in PCB. The reliability of the PCB can be increased by teardrop-shaped vias or junctions since they offer some redundancy for the via.
A teardrop is the excess coper at the pad/trace connection, as shown in the figure. It sits right at the point where the trace thins out. In the printed circuit board (PCB) sector, it is normal practice to include teardrops if you are undertaking micro design for the first time.
In light of this, the goal of this article is to provide a comprehensive overview of teardrops in PCB and how they contribute to the increased stability of a PCB.The process of its production and any associated issues will be revealed. Finally, we’ll demonstrate how to use some built-in features of the PCB design program to fix these issues. So, let’s not waste any more time and go in.
If you are interested in learning more about how we have used PCBs in the past, you can look through some of our older articles. If you’re unfamiliar with PCB design, you may find our essay on the fundamentals helpful.
What is a Teardrop in PCB?
I first learned of teardrop metaphor when reading about one. Tears? was my first thought. IN PCB? The heck is that? My coworker recommended that I look it up online. It took me a while to figure out what teardrops meant because there wasn’t much information online back then.
The accompanying image illustrates the striking contrast between a teardrop via and a standard via.The tiny form on the image’s right side is called a teardrop through because it resembles a teardrop, yet in the broader scheme of things, this teardrop seems superfluous. If this is something you’re wondering about, keep reading!
As can be seen in the above image, the manufacturer made a major error, as mistakes are inevitable when producing a large quantity. Sometimes there are problems with the laminating process, the drill could wobble, and so forth. Although every effort is made to ensure the highest quality, manufacturing errors do occur. In addition, if something goes wrong, you might drill a hole elsewhere besides the pad or via.
By increasing the amount of copper beyond the pad in a tiny way throughout the design phase, teardrops can protect against drill breakouts. If the drill hole is on the other side of the trace, the track connection is unaffected, but if it is at the point where the trace meets the pad, it can lead to major issues.
The next logical inquiry is, how wide or narrow should the teardrop be?The manufacturer’s instructions are the definitive source, however here’s what we do as a matter of thumb:
Apex Radius Factor = ((Diameter of the PAD - Diameter of the Hole)/1.8)
While doing a large PCB design, this gives us a general idea of how the teardrop setting will be.
Adding Teardrops in Your Design
Following the manufacturer’s requirements for testing and inspection is essential before placing an order for printed circuit boards (PCBs). Typically, the manufacturing facility will also provide teardrops as needed; nonetheless, it is recommended that you include your own teardrops just in case. Remember that teardrops aren’t necessary if your trace width is more than 0.5 mm.
Adding teardrops in eagle:
As you can see, we’re utilizing Eagle PCB designing software to create our PCB, and the settings and options we’re employing are exclusive to that program.
Eagle’s teardrops can be created by selecting the ULP icon from the main menu, typing in “teardrops,” and then double-clicking the result. Simply enter the teardrop’s radius and press the OK button. The teardrop’s radius can be determined using the aforementioned formula. Do a thorough DRC and ERC check after adding the teardrops to ensure that no teardrop vias are touching.