Before I pick a component for a PCB, I am trying to make sure it would not become obsolete in the near future because it's a mess and it happened to us a few times.
How would you check if a chip is going to have at least a few years of life?
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7\$\begingroup\$ Well, did you ask the manufacturer? \$\endgroup\$– Vladimir CraveroApr 6, 2017 at 7:29
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2 Answers
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Ultimately, you can't.
Some manufacturers have a policy of supporting chips into the future, and assure customers that they will be available until a certain year, or that you will have (say) 5 years' notice of withdrawal. That's better than no assurance, but if they go belly-up, then a notice period becomes meaningless.
If you can estimate how may PCBs you will make, and can afford the stock, then you could make a one-time buy. This is rarely an option. If your market suddenly exceeds your expectations, than that's a 'good' problem.
Ideally, choose chips that are available from several manufacturers, to the same specification. The chance of them all going belly-up at the same time is small, but the chance of the market changing and causing them all to withdraw for economic reasons is higher. Of course, there are a huge number of 'interesting' ICs that are only available from one source.
You can have an obsolescence plan, to minimise disruption if you lose supply of a vital component, to allow you to mitigate its loss fast. Depending on what it is, write it in C rather than assembler, write it in VHDL rather than a graphic design tool dedicated to the supplier, have extra space and extra power available nearby so that if forced to replace it with components on a daughter board, you're not forced into a bigger re-design.
It only tends to be the military who want 30 year repair or production life. The way 99% of other people work is that a new model of the end equipment (which needs newer components to be designed in) is needed before the components that make up the old one become unavailable. It's a risk, but alongside all the other business risks, most people don't get stung by it.
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\$\begingroup\$ Thanks a lot, but if we are talking about micro processors, or bluetooth LE chips, those are made by a single manufacture you chose, which means if you adopt one, you can't just copy paste your code into a new one from a different company later on. \$\endgroup\$ Apr 6, 2017 at 7:51
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2\$\begingroup\$ No you can't, but as Neil says you design in such a way that you make the job of switching as easy as you can. Layer your code so that the hardware handling is separated from the higher level and use high level languages where you can. There is a massive range of PC hardware out there but it can all run most software because of the way the whole system is put together. \$\endgroup\$– FinbarrApr 6, 2017 at 9:08
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1\$\begingroup\$ It's also worth pointing out that there IS some degree of second sourcing out there. Lots of manufacturers build devices around the same ARM cores and other manufacturers make PIC-like devices. Plus the obvious x86/x64 ranges compatibility between Intel and AMD. \$\endgroup\$– FinbarrApr 6, 2017 at 9:16
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2\$\begingroup\$ Good post, but I disagree somewhat with your conclusion that it only tends to be the military who wants long production/repair lives -- industrial control systems have a habit of long lifecycles as well. (My employer still has 70+ year old relay logic systems in active field use.) \$\endgroup\$ Apr 6, 2017 at 11:46
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1\$\begingroup\$ One thing that can help somewhat is to piggyback on the fact that the automotive world takes a very dim view of parts obsolescence, and has the weight to make this stick. Buying automotive qualified parts, while no guarantee does seem to cut the annoyance down somewhat. \$\endgroup\$ Apr 6, 2017 at 12:34
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Texas Instruments is probably lucky to have its own manufacturing plants. I've heard over and over that they'll keep building a chip as long as people are buying it. I'm sure the fine print somewhere says "as long as you buy enough quantity". The "hero" devices will definitely never go away (MSP430G2553, CC3200, and AM335x are a couple).