Products are designed with a lifecycle of at least 10 years. Within that time period, it is inevitable that there will be an issue with one of the components in the original BOM. The problem may be as minor as low inventory stock or something major, like a “last time buy” lifecycle change.
You can avoid a premature redesign and secure the product’s 10 year lifecycle by finding a proper cross reference. Use these seven factors when considering an alternate to solve a lifecycle or a supply chain issue.
1. Ensure Form-Fit-Function
Finding another component with the same form-fit-function, is essential to evaluating an alternate part. To find-form-fit function similarities, use only the latest datasheet from the manufacturer to compare parametric attributes to ensure an accurate match.
What is form-fit-function?
- Form: the physical aspect and parameters of the part such as the size, weight, package dimensions.
- Fit: the way a part connects to the PCB board, such as the same footprint and mate. Fit factors in if your part’s package type is a surface mount or a through hole.
- Function: the actions the component is intended and expected to perform.
A component with the same form, fit and function will allow the designer to use the two parts interchangeably. Systems with grading features, such as the SiliconExpert Cross Type Grade, compares how closely related the alternative component is to the original at a glance. SiliconExpert’s grade rates components on a scale of A-F, based on pin-to-pin parametric values.
2. Lifecycle and Forecast Obsolescence Date
Is your alternative part still in the market? Get confirmation from a reliable source, such as a direct manufacturer datasheet, to ensure the part is still active and is not in the “last time buy” or “not recommended for new design” stage.
Before selecting a part as an alternate, ensure it has a long lifecycle. Utilize forecasting data to assess the years to end of life and match your findings with the longevity of your product. Selecting a part with a shorter lifecycle may lead to premature redesigns.
3. Comply with Regulations
Ensure regulation compliance for your alternate parts. Check material declarations or a Certificate of Compliance (CoC) to understand the material buildup. Does it contain 3TG minerals from the Democratic Republic of Congo, which is banned by the Conflict Mineral Regulation? Is the alternate RoHS and REACH compliant? Sell products internationally by ensuring compliance across all regulations.
4. Survey Market Availability
To avoid procuring the alternate from an unauthorized vendor, several distributors should be carrying the part. Check multiple distributor websites (such as Digi-Key, Arrow, Avnet, Mouser etc.) to ensure the part is available from multiple sources. Remember to confirm that adequate inventory is available from each distributor, as well.
5. Look for Counterfeit Reports
If the alternate component is not available in authorized distributors and is procured from unauthorized sources, look for existing counterfeit reports. Industry counterfeit reports can be found from reporting services like GIDEP, who releases reports regarding emergence of counterfeits. Alternatively, industry-wide collaboration is another effective tool for mitigating counterfeit risk. By utilizing third party tools (such as SiliconExpert), users can flag the likelihood of counterfeiting when searching the parts database.
6. Part Manufacturer Reliability
When choosing a part, evaluating the manufacturer reliability is usually overlooked. Most companies have a list of trusted manufacturers, which make up their ACL (Approved Corporate List) or AVL (Approved Vendor List). If the alternate part is designed by one of the manufacturers on this list, there is no problem. If not, you should research their financial background, history and top customers. It’s always reassuring when you find a manufacturer is commonly used by many other companies.
7. Gather Additional Crosses
Lastly, when evaluating a part that will be cross referencing your original part, ask if there are additional crosses for that part. It may sound strange, but does your alternate have other alternates? This can broaden the range of components to choose from if your alternate goes obsolete.
When evaluating a cross reference proactively for the future or immediately, keep this list handy to preserve the product’s lifecycle without having to do a full product redesign.
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