In the first of this series of articles on common printed circuit board design problems, we talked about how a circuit board begins with its design and layout. While that is true, it is also appropriate to say the design itself begins with its components. Without the correct components to perform the required tasks, a circuit board is little better than an expensive door stopper. Engineers need to select the right components for the job and for manufacturers to have abundant access to those parts. Unfortunately, this isn’t always the case.
This next part of the series will examine the problems surrounding the selection and use of components in PCB designs. Not only do designers need to carefully select the parts that will best serve the needs of the design, but there are also a host of supply chain issues to keep in mind. By examining these issues, you will be more equipped to resolve some of the common circuit board problems involving components.
Four Common Problems When Selecting Components for a PCB Design
Design engineers will already have a pretty good idea of what they need for the circuits they are creating when it comes time to populate a PCB design with components. Where the problem comes in is in how those parts are selected for schematic capture. Without the proper amount of care in their selection, design engineers may end up with parts they didn’t expect or intend. Here are the four main problems when selecting electronic components for the design:
1. Convenience
It’s easy to get into the habit of repeatedly using the same parts in a design, especially common parts like decoupling caps or terminating resistors. However, components can change in their availability status and price over time, resulting in a design full of unavailable parts. This problem also appears when copied circuitry is used or the designer fails to check for the latest updated parts.
2. Functionality
Another problem can occur if design engineers can’t find the parts they need and choose less than desirable alternatives. Perhaps they didn’t search for similar parts with other vendors or see if better substitutes or combinations of parts were available. In some cases, redundant circuitry is left in the design, which in itself isn’t so much of a problem as it is an unnecessary use of time and money.
3. Out-of-date CAD libraries
PCB CAD libraries can become stagnant over time if they are not properly maintained. Electronic components will change during their lifecycle, and design departments must update the corresponding library parts to reflect this. Parts that have become obsolete or unavailable must be marked or removed from the library to prohibit their use in new designs. This library maintenance also includes ensuring that the schematic symbols and the PCB footprints match. Many designs have ended up failing during manufacturing because the schematic symbols called out the wrong PCB footprint.
4. Lack of resources
In some cases, designers can make poor component choices because the engineering department lacks resources. “Who do we contact,” and “where can we get the best prices” are typical of questions that design engineers ask. Without a network of component resources, designers can end up choosing parts that are too expensive, low quality, or aren’t the best fit for their needs.
These are examples of some of the problems that can occur with choosing the best parts for your design. However, beyond that, there are even worse problems waiting to snare design engineers who aren’t prepared for them.
Supply Chain and Common Circuit Board Problems with Components
Everyone knows that there is a severe part shortage in the global supply chain for electronic components. Here are some of the details of this shortage that you should know about:
- Caught off guard: Integrated circuit foundries were surprised by the unexpected electronics demands over the past couple of years. While initially shutting down due to the COVID-19 pandemic, the automobile industry suddenly rebounded, thus requiring their usual quantities of parts. Unfortunately, many foundries had switched over production to supply other products that had risen in popularity, such as home computing and entertainment. This situation has left the foundries scrambling to meet demands, and they fell behind.
- COVID-19 pandemic influences: While the COVID-19 pandemic changed the world’s electronic needs, it also affected how those electronics were manufactured. Several industries reduced production due to shutdowns, illness, and workers sheltering-in-place. These changes created a shortage of laborers and materials, impacting the chip foundries from fabricating more components.
- Shipping problems: As the world of manufacturing changed, so did shipping. Traditional shipping channels became clogged trying to meet unexpected demands, while at the same time, taxes, tariffs, and trade wars made the problem worse. On top of that, political unrest and the continual issues triggered by the pandemic only worsened the shipping problems.
- Hoarding: To ensure their manufacturing continues without interruption, many larger OEMs will bulk purchase specific parts as soon as they are available. These blanket component purchases put smaller OEMs at risk when they cannot find the same parts for their own manufacturing.
- Counterfeiting: An old expression claims, “In confusion, there is profit,” which has certainly proven to be true during the shortage. Component counterfeiters have increased their activities to capitalize on the desperation of OEMs to find parts for their projects. Many victims have ended up with outdated components or general parts sold as precision components for higher prices.
While it would seem like purchasing and assembling components to a circuit board would be a straightforward operation, there can be, as we have seen, many potential problems to overcome. Fortunately, there is a resource available to you for help.
How your PCB Manufacturer Can Help with Your Component Selection
PCB contract manufacturers usually have experienced component engineers and procurement specialists to help you with your part selections. At VSE, we have been working with our customers for over 30 years on component selections. We have developed a trusted network of component manufacturers, distributors, and brokers that we work with regularly. Our engineering staff can help you choose the best components for your design based on function, price, and availability and recommend design changes to support alternate components if needed. We also have strict procurement and incoming inspection processes to guard against counterfeit parts and ensure that once built, your circuit board will function the way you intended.
