What is the Alternative to Using a Via in Pad?
Alternative to Using a Via in Pad
As electronic components continue to shrink in size, PCB designers must adapt and implement new techniques to route them. One method that is growing in popularity with engineers is via in pad, which allows signals to travel directly from a component’s pin to the pad on which it sits. While this technique has its benefits, there are also several key considerations that should be taken into account before using this design approach.
A capped via in pad is a process that involves filling and then capping the bottom of a via hole. This is done to ensure that the trapped air within the hole does not outgas during assembly. This can be a significant problem when working with smaller devices and high-speed nets, as outgassing could potentially break the solder joint and result in poor connectivity. In order to prevent this from occurring, a non-conductive epoxy is first filled into the via hole and then capped before it is plated with copper. This adds an extra step to the manufacturing process, which can sometimes result in a longer lead time and increased cost for a circuit board.
This method of via in pad is useful for high-speed designs, as it decreases trace length and thereby inductance. However, it is important to verify with your contract PCB manufacturer that they are well-equipped to do this, as it requires a different process than traditional routing methods.
What is the Alternative to Using a Via in Pad?
Another benefit of this technique is that it can help reduce heat build-up on a circuit board, which can extend the lifespan and reliability of the device. It is able to do this by minimizing the space between elements, reducing parasitic inductance and allowing for shorter paths to power and ground planes that can minimize EMF emissions from high-frequency signals.
The downside to this type of routing is that it can increase the amount of design rule checking required, due to the need for a minimum annular ring. It can also cause problems with sizing, as the pad must be large enough to accommodate both the via diameter and the component/device footprint. In many cases, a standard solder mask can be used to “tent” the pad instead of using a capped via. This is a much simpler solution, but it does not provide the same level of protection against voids and short circuits.
As technology continues to evolve, it is crucial that hardware engineers keep up with the latest developments in printed circuit board design. By staying informed about the pros and cons of various design strategies, engineers can choose the right route for their projects. If you have questions about the use of a capped via in pad or would like to discuss other routing options with our team, reach out to us today! We’re happy to answer any questions you have and provide recommendations based on your specific project requirements. Our engineers are highly experienced in helping you create a high-quality, reliable product.