New Designs with Obsolete & EOL Components? - Page 1
Forum section: electronics / projects

author: Dave8266
author_rank: Contributor
timestamp: September 28, 2020, 07:00:25 pm
content: Just curious, for those doing small production runs, what is your personal tolerance for making new designs using components that are obsolete, "Not Recommended For New Designs", "Last Time Buy", or otherwise at their end-of-life status?Of course the general guidance is to not use any parts in those categories if you can avoid it, and companies go to great lengths to manage the supply and substitutions of parts, and the associated circuit redesigns that future substitutions require. But I couldn't count how many times I've had an idea for something, and found an IC that perfectly performs a key function, but is in one of these EOL categories. For one-off hobby stuff, it's no big deal. But for low-volume production, and particularly new designs, maybe not so clear?It's harder too when a part is full-on obsolete (not even last time buy or NFND), but the suppliers have tens of thousands of them in stock. *My* products would be obsolete before that obsolete component became unavailable.I'm curious how other people approach this.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: September 28, 2020, 07:07:06 pm
content: Anything I think will be a low volume "one-off" turns into a continuous production item for years to come. Things that I plan out for years, knowing what a success they'll be, die an early death. Other than hobby stuff, if it's EOL I don't use it. Careful though, EOL at one place might still have a stable second source for years to come.

author: TimNJ
author_rank: Super Contributor
timestamp: September 28, 2020, 07:08:52 pm
content: I don't think I could live with that rain cloud of uncertainty over my head. Distributor stock can vanish over night.Only way I'd ever consider it is if we bought enough stock ahead of production, to last essentially forever. But then you have to worry about things like proper parts storage, MSL, etc. If you have systems and procedures to handle that...maybe.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 29, 2020, 01:47:22 pm
content: When an obsolete part is out of production, there is no way of reliably predicting how long existing stock will last. Your "tens of thousands" of parts in stock can be bought by a single person with slopply inventory managment who at some time realizes that his important part is out of production.Then there are special cases.There are some blogs on the Olimex website about an obsolete processor from Allwinner (I think the A13)There is some connection between Olimex and Allwinner, and apparently Allwinner re-started the factory to make a batch of 50.000 of these processors for Olimex.It's one of those differences between the culture of Chinese and "Western" companies.On the west side of the dirt ball they say: Sorry, it's obsolete, bad luck.The Chinese take out their calculator and if there is a profit to be made they do it for you.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: September 29, 2020, 03:03:24 pm
content: As I am just a small outfit I try not to use SMD as through hole is easier by hand for me.Having said that some SMD packages are ok like SOICI use a PIC32mx274 SOIC 28 quite often but that is no longer stocked by Farnell so I have to buy from RS Components.As time goes on the amount of through hole stuff is diminishing.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2020, 04:03:57 pm
content: An important factor is also if there is a good substitute I would have not problem planing with an EOL part if there is an alternative though slightly worse or currently slightly more expensive.It can also be the other way around: if the obsolete part makes the product so unique and one can still get a reasonable stock, why not use it. One such case may have been the BF862 low noise JFET a few years ago. AFAIK there is still no direct 1:1 substitute with the same trans-conductance / capacitance ratio, and it was called obsolete with still quite some stocks around. So if you still have a role, why not use it.If possible avoid old obsolete stuff - you never know if you need a few more, even if just for repairs.

author: SilverSolder
author_rank: Super Contributor
timestamp: September 29, 2020, 04:37:14 pm
content: Quote from: Doctorandus_P on September 29, 2020, 01:47:22 pmI think we used to be more like that in the West. Nowadays, everything has to go through so many stages of approval that even making a toothpick becomes a major, expensive project! Assuming you can even log in to your corporate computer to get started, given all the security precautions!

author: IanJ
author_rank: Unknown
timestamp: September 29, 2020, 04:49:48 pm
content: I use a lithium-ion batt charger IC in one of my products. My usual sources suddenly listed it as no-stock/obsolete......so i contacted the manufacturer who said it wasn't obsolete, was still current and no plans to change that.......and how many did I want.Don't believe everything Farnell/RS/Digikey tell you.Ian.

author: Dave8266
author_rank: Contributor
timestamp: September 29, 2020, 06:11:28 pm
content: Thanks everyone, good points made all around.Difficulty of replacement is part of the equation for sure. Doing a pseudo-lifetime-buy to last a few years of production/repair and simply planning for a board revision later often seems well worth it, when the alternative is a sustainable, but more complicated layout/BOM or process - especially when the only suitable replacement for those obsolete ICs are microcontrollers and the associated process overhead of programming them before populating the boards.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: September 29, 2020, 06:22:28 pm
content: Quote from: IanJ on September 29, 2020, 04:49:48 pmYes, in that respect, sometimes what distributors say can be misleading.I used a triple half-bridge driver chip in one of my projects (nothing special, just a hobby thing), and I wanted to later buy some more. When I looked it was listed as 'obsolete'/'discontinued'. But manufacturer's website said it was still an active product. I was puzzled until I found a product change notification document that said that they had changed factory, and thus had decided to change the part number. New part number showed as 'active' and massive stocks.