Component Selection in PCB Design
Components are Essential
PCB Design begins with component selection, the components make up the other aspects of the design: The schematic ties components together by generating a net list; The layout places components and routes traces to connect components according to the net list. This makes component selection the building block toward a completing a manufacturable circuit board design.
Availability is a Must
Availability is the first thing I check when screening potential components. It includes both current and future stock with distributors. Current stock can be checked using the built in filters on distributors’ websites including the characteristic that an item is in stock. I also like to check the amount of stock available, the component may be available but if quantities are too low it won’t be sustainable in production. The amount of stock may also be indicative of how many manufacturers are using the component. With components there is strength in numbers, the more manufacturers buying the components the more likely the component life will continue.
If I find a component that is a good fit but the stock is too low at a certain distributor, I like to check other distributors in case they do have enough stock. Octopart is a search engine I use to check stock across many different distributors.
Future component stock will be impacted by whether the product is active. Popular distributors such as Digikey and Mouser often allow customers to filter out inactive components on their website. Finding the component on the manufacturers website is another good way to check component status. If it is labeled as EOL (end of life) or “not recommended for new designs” then, with a few exceptions, the component may not be a good fit for the design.
Choosing components with compatible replacements from different manufacturers is a good practice in component selection. Although it is not always possible, it provides an off the shelf replacement should the primary component ever be unavailable. Finding components with compatible replacements includes designating the component package. Often components are offered in more than one package and choosing the package with compatible replacements could help avoid redesign later. Don’t forget to compare the pinout as well, just because components have the same package and functionality doesn’t mean they have identical pinouts
CircuitBoardLayout.com can assist you in your component selection by providing advice and sharing techniques and methods that you can use in your component selection process. If you’ve already selected your components and are looking for PCB design, you have come to the right place.
Also, stay tuned for more information on specific component selection such as capacitors for power supplies, and component selection for boost and buck converters.