Any active electronics product should be checked periodically to make sure its components are still available. Perhaps this is annually, quarterly, or twice a year when you change your clocks. This review will help you keep a healthy electronics supply chain with a managed approach to electronics obsolescence.
Your new printed circuit board assembly (PCBA) WILL become obsolete
Any electronic printed circuit board assembly will eventually become obsolete. Sometimes it is because there is better technology to get the job done, like CDs replacing cassette tapes, or LCD televisions replacing CRTs. Other times, it is because some of the components selected become unavailable. This may happen for a variety of reasons. Perhaps one chip company bought another and made a business decision to discontinue the component. Sales may have slowed to the point that continuing a component was no longer economically feasible. Industry trends such as going lead-free or RoHS may have ended a component’s future. Whatever, the reason, the component is no longer available and the circuit board that used it is now obsolete.
Did you plan for obsolescence?
When the PCBA was designed, was consideration given to how long it should last? If it was cutting-edge technology, it may not have been as important since better technology may have become available within a couple years. Maybe it was just an interim product on the way to a more permanent model. If it was a simpler, more straightforward design (a power supply would be an example of this), it would have been useful to have it available for years to come. Whatever the case, it’s important to plan for the desired lifecycle and choose components that are likely to be available throughout the design lifecycle. If this step was skipped, it’s still not too late to do the exercise to know how long the PCBA will be needed.
Monitor component availability
One thing that can be done to test obsolescence is to check on the current availability of all components on the bill of material (BOM) with various electronics distributors. This will expose any parts that are currently obsolete and parts that may have limited availability. This can be done by just about anyone without subscribing to a component database platform and is an important step to do periodically.
A more thorough approach would be to subscribe to a components database that contains more extensive information on lifecycle expectations and availability. Even if this approach is chosen, things change and it should be checked periodically.
Regardless of the method chosen, when planned for, this is a quick check that can avoid major problems.
My BOM has an obsolete or unavailable part, now what?
Even if you planned and monitored for the product’s lifecycle, you may find an obsolete part has surfaced. Maybe a component reached its end of life earlier than expected. Perhaps your product has demand longer than expected. These are all much easier to handle if the BOM was regularly monitored. If a component is found to be obsolete, the entire BOM should be checked to get a big picture of how many more components will potentially be obsolete sooner than expected for proper planning. Here are some mitigating actions to extend the product life (most actions can also apply to long-lead parts):
In order of preference:
- Choose an alternate drop-in component
Fortunately, many times an exact replacement is available to replace an obsolete component. If it was a passive component, such as a resistor or capacitor, it is likely that another manufacturer makes the exact replacement. If it is a more specific integrated circuit, the manufacturer will often recommend a replacement. Whenever an alternate component is chosen for a design, it should be tested to confirm that it actually was an exact replacement.
- Last time buy
When a company discontinues a component, they usually provide notice and allow companies to purchase as many as they need up to a certain date. It becomes critical at this point to decide how many more PCBs will be needed and purchase the necessary quantities. When placing this order, don’t forget to account for extra quantities to support existing product already fielded.
- Purchase brokered parts
Brokered parts are the last option to avoid a redesign, but may be a means to kick the can down the road. If this is the last alternative, these parts won’t be available long and should be considered similar to a last-time buy. Word of warning: don’t just buy parts from any broker. You need to vet the broker so you don’t introduce counterfeit parts into your supply chain. (Read more about that here.)
- Minor PCB design change
This is the least desirable thing to have to do, but may be necessary. If there are no parts available that can be used as alternates, a design change may be the only option. This may be able to be accomplished without a layout change, or at least only a minimal change. Many times, only a small portion of the board would need a design change. If it has gotten to this point, you may want to revisit the entire PCB layout and any enhancements you would like to add.
ACDi can assist with obsolescence management, including planning, periodic checks, parts supply, and even PCB design changes.