Column: Embedded design


critical to your favourite product cannot be had for love nor money. We, as engineers, can’t stop a part from going obsolete … so how can we reduce the pain? Well, the commercial ameliorations


remain the same as they always were: Maintain deep stock of absolutely critical parts, monitor the announcements from distributors and manufacturers, and work closely with marketing and production to keep valuable product designs updated. However, there are a handful of approaches and ideas that might not be immediately obvious: 1. When a part goes obsolete, or otherwise cannot be found any more, directly contact the original manufacturer and ask them for help. Sometimes (rarely) they may have an alternative that you’ve just not spotted, or they also might know where significant stock can still be had, or (and while very rare, I have actually seen this happen) they might be prepared to put a beloved part back into production, if a significant order can be placed.


2. Study (and I can’t think of a better term) the “personality” of your key part suppliers. Some companies are quite simply more prone to withdrawing parts (even popular ones) than others. Once you have a good idea of who the “offenders” are, avoid them, since it’s not worth using an excellent looking new part from a supplier who you know has form for declaring an end of life after a few years.


3. Similarly, maintain a careful watch over industry buyouts, mergers and acquisitions. New brooms are disagreeably fond of “clean-sweeping”, and if a known “bad” company buys


Don’t forget: if you designed it before, you can design it again without those troublesome parts. With a bit of luck, it’ll be better!


out one of your “good” suppliers, then you know that trouble is on the horizon. Certainly in the RF sector, I’d go so far as to say that any acquisition or merger will result in wholesale loss of products, irrespective of the promises given by the “aggressor” company.


4. Watch industry trends, and look for once popular product areas falling into decline. In this case it’s worth carefully inspecting the suggested applications in manufacturer’s data sheets and in the annoying “applications” sections of their websites. If a part is very strongly slanted towards a particular product area, even if it isn’t a specific niche part, and that area slumps, then expect trouble. The case in point here that I can cite is analogue car radio. As DAB has become more popular, many of the very useful RF JFET parts that were promoted as lower frequency antenna pre-amps have disappeared. Something similar is currently happening among the GPS-band LNA chips, where the seems to be a significant shake-down underway. From an actual design point of view,


the obvious advice to use common pinout parts remains as salient as it


ever was, but a less well appreciated consideration is overall size of a product. Fight for every last square millimetre of PCB area (not forgetting the Z axis) and use (or allow for) the largest parts that you can use. If you’ve designed around 0201 resistors or SOT723 transistor packages “because they are new and cool”, and a part goes unexpectedly obsolete, then you aren’t going to be able to substitute a larger package,. If you’d designed to use the available space with bigger packages, then you will always be able to scale down in the future (even if it requires a simple PCB revision). In some cases, using an older leaded part (I make use of a lot of HC49 footprint crystals, where I can) gives you the future option of re-draughting around smaller SMT parts when you need to. Obviously this isn’t an absolute (no-


one wants a smartphone the size of a house brick), but in many situations a product design isn’t primarily driven by physical dimensions, and in these cases it’s foolish to work as if that is the case.


Worth noting The important thing to remember is that obsolescence happens through human decisions; the laws of physics have not changed. If you have a market for a product,


there is no reason to let someone’s random decision deprive you of it. Keep your nerve, try all the options, and don’t forget: if you designed it before, you can design it again without those troublesome parts. With a bit of luck, it’ll be better!


Tis column on embedded design prepared by Myk Dormer continues in the next month’s edition of Electronics World.


www.electronicsworld.co.uk November 2025 13


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