I started playing chess a bit more seriously a few years ago and have since become quite capable of planning out moves several turns in advance with an accurate prediction of how my opponent will react to them. I wouldn’t even consider competitive with my chess skills, but there are professionals who can predict moves and match outcomes between 60 and 100 moves in the future. While it’s a strong practice to get into, being able to predict moves accurately, it isn’t without fail; in fact, the more constrained your imagination is, the more likely you are to be surprised with a counter-move that you hadn’t predicted. Being able to accurately predict future moves is important, but leaving room to adapt and redesign your game plan is just as important for your game.
Part of getting more involved with chess over the years has been learning to adapt my strategizing to several other areas of my life: I’ve started planning out home renovation projects with steps and predicting hiccups; my work, especially, has benefitted from being able to plan forward: designing electronics for manufacturing in the real world involves many steps. Requirements are defined, circuits designed, concepts tested and refined, components checked for compliance, prototypes built and proven, and the betas run in. Then you take a breath if you can, and remember you’re maybe halfway there. Burn-in and testing are figured out, suppliers are approved, manufacturing documentation completed, compliance is verified, and the production order is finally placed. The job is done, right? Well, hopefully, responsible engineers have kept the following points about electronic parts obsolescence in the back of their heads during the whole process, because sooner or later, it will likely become an issue.
Opening Move: Component Selection for Parts Obsolescence Management
PCB design has a long list of necessary actions and moving parts to keep track of. It might be tempting to default to certain products for your components; however, selection of a specialty component can save a lot of legwork. Integrated circuits designed with a specific task in mind can reduce your component density, make a layout cleaner, and help make the PCB smaller (a hugely popular trend in PCB design). The downside with a specialty component, though, is that they might not be around in a few months when you need them. Even common circuit elements that have been used for years might be on their way out if another technology ascends the throne.
One of the ways you ensure up-to-date component selection is through keeping informed on industry trends and technological innovations. When that isn’t enough, you might find that checking if a component is right for your application involves more than a thorough review of the data-sheet and the ensuing design and test rigamarole. For any non-standard components, it is a good idea to check not only its product life status but the status of possible alternative components. If any of them have been flagged for Last Time Buy (LTB) or as End of Life (EOL), it may be the start of a trend that you don’t want to be a part of. Part of careful planning for manufacturing and use is predicting the ways in which design innovations might affect your boards in the future.
Planning can help avoid your PCBs running out of functionality before their time is up and save you money.
Surprise with Your Design for Manufacturing Strategy
Many new gadgets are expected to leverage the latest technology. The continuing rapid advancements in the development of the microprocessors used in many designs means that product life-cycles are becoming shorter. This opens up the possibility of planning for other changes during scheduled redesigns based upon components with known short life cycles. Only familiarity with your own customer’s requirements and expectations can help to determine the effect this should be allowed to have on your design. Ignoring a Not Recommended for New Development (NRND) status might necessitate an LTB purchase, but if you’re designing for a known quantity of this season’s hobby drone controller then ignoring the status might be acceptable.
But beyond planning around customer needs, the practice of designing a board to accommodate eventualities has been called “putting the hooks in.” This term originally referred to the adding of hooks for test probes at important points in the circuit but has come to include the addition of extra pads for unpopulated components as well. One way to put some hooks in to guard against part obsolescence is to design board layouts or part footprints that can accommodate multiple design solutions or components. Such an approach can help use inventory from previous LTB to free up inventory space and potentially save time, energy, and money. When the space on the PCB is available, and there is time to evaluate multiple configurations, including both solutions on your layout can add a lot of versatility. I caution that this isn’t a viable approach for high speed nets—unused traces can cause reflections that add to signal noise which might be disastrous.
Don't Use a Pawn When It Takes a Rook
One thing that anyone who has spent time in the industry realizes is that sooner or later the dreaded Parts Change Notice (PCN) forecasting an EOL will find you. Hopefully, it arrives with enough time to evaluate options and make a good decision before the LTB due date. Your options become finding a direct pin compatible replacement, planning an LTB purchase (and dealing with an upfront cost and warehousing of parts), designing an interface board for a non-form-fit-or-function replacement component, or redesigning the board itself. Since this decision does come with a due date, it is important to have good tools at your disposal. Making the wrong decision can incur extra expenses, unnecessarily take up valuable time, or even lead to products that do not work correctly.
Don’t let surprise part obsolescence take up more time and energy than necessary.
By using a smart bill of materials management software, you enable yourself to get direct, real-time insight into industry trends and history. You can configure the BOM to provide information about current supplier part status, availability, and present alternative parts that save you time and money to keep your design moving. With direct communication between manufacturers, designers, and suppliers as well as easy inventory management, Altium’s BOM software gives all this and then some.
If you’re looking to learn more about the benefits to having a smart BOM management software, consider talking to an expert at Altium today.
About the Author
PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.More Content by Altium Designer