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How to Save Yourself When You Can't Find a Part

Published Date

Estimated reading time: 4 minutes, 40 seconds

(Image Source: Maks_Lab/Stock.adobe.com)

Published July 6, 2023

It happens: A key component in your BOM isn't available. Typically, this results from supply chain shortages or lifecycle changes. But before sourcing a substitute part, it's essential to understand if you're looking for an alternative, equivalent, or drop-in replacement.

  • Alternative components may not have the exact specifications, footprint, symbol, or features, but they are configured to adequately perform the required design functions.
  • Equivalent components have the same (or close to the same) electrical specifications as the missing component. It may be a manufacturer part number (MPN) variant but housed in a different package. Not all components have an equivalent.
  • Drop-in replacements are components with the same symbol, PCB footprint, and pinout as the unavailable part. Drop-ins are commonly used for nearly identical parts available from multiple manufacturers. More specialized components may not have drop-in replacements and will require some redesign.

Source a Substitute

Sourcing involves strategy, processes, and consistency. Start by establishing a good relationship with a distributor. Work with the distributor's technical support to identify a component with the exact fit, form, and function. Use a distributor's parametric search to select specifications and see if an alternative is identified.

For example, Mouser's Services and Tools page provides valuable resources for designing and engineering, quoting, and purchasing. It offers efficient, time-saving solutions, including the FORTE Intelligent BOM Tool, order automation resources, and an extensive ECAD design library. Mouser's Help Center is a single destination for convenient customer support. The searchable Help Center provides customers with the information they need to find a specific part or request a quote.

In addition to distributors’ resources, the following steps can help you find the right substitute part:

  • Begin by searching for a substitute part within the same family of parts by the same manufacturer.
  • Use electronic component search engines to locate components by manufacturer name, MPN, product line name, component type, and specifications.
  • Identify any drop-in replacements first. If none exists, search for variants of the unavailable components or identify an equivalent by searching based on electrical ratings and component type. Perform a general search for the component type to identify alternatives.
  • Search third-party component databases, which offer a view into millions of components from thousands of suppliers. These databases often include obsolescence forecasting, inventory data, and compliance data, including notices on restricted and conflict materials.
  • Make sure that the substitute part will likely remain available in the near and long term.
  • Account for the time needed for engineers to test the substitute part—a necessary step.

If you’re unable to find a suitable replacement part, the engineering team may have to consider a redesign that removes the component causing delays or replaces it using a more common material or component.

Check Requirements

You're charged with finding substitute parts, so what do you need to do? First, always work directly with the design engineer so that all identified parts meet the design’s needs. Start with the following questions:

  • Is the original part in danger of being obsolete?
  • Is it recommended for your design?
  • Does the substitute part need to be easy to find in two to three years?
  • Will it represent a considerable cost for the overall project?
  • Is the source authorized?
  • What is the lead time?
  • Will the substitute part completely solve the problem?

Be aware of any legal or regulatory considerations when selecting substitute parts. Check whether the parts meet required quality certifications or government regulations and consider any country-specific restrictions.

Communication between purchasing and engineering is critical. Once you have identified potential substitutions, gather as much information as possible on each, including availability, price differences, lifecycles, certifications, and where they are sourced from. Provide information on the possible substitute components to the engineering team and ask for confirmation that they will work in the application.

Assess Risks

There are risks involved when sourcing critical components, and due diligence is mandatory, especially when working with new vendors. The component shortage realities of the past have spawned an increasing number of bad players in the market. Scam artists pose as reputable part vendors with stock available to ship immediately.

These bad players now use search engine optimization to create accounts on popular e-commerce platforms and offer hard-to-source components. Once paid, they deliver fake or defective parts with devastating results. Additionally, some online marketplaces may not verify component legitimacy, leaving buyers vulnerable to counterfeits. To avoid counterfeit and other harmful components, it’s important to buy only from authorized sources.

Obsolescence is a manageable risk if you take the time to do it. All electronic components have a run date, and manufacturers update lifespans with inventory cataloging. Avoid the risk of shortages and soaring prices for rare parts by actively predicting obsolescence.

When parts are not well vetted, there's a real potential for failure on the board. Risks also include cost increases, especially when delivery must be rapid. And, of course, there's the potential risk of not being able to find a substitute for the part you need.

Stay Several Steps Ahead

Sometimes you may need to quickly find substitute components because of circumstances beyond your control; but avoiding these situations is the best approach. For example, informed forecasting will help identify when parts are moving in and out of their lifecycles and if the manufacturers offer revisions. Be current on new materials development. Stay current on trends and developments in the market for alternative parts and share findings across the team.