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Analog Angle Blog

Vendors Are Gone, but Their Prefixes Are Not

I was looking at the schematic of a relatively new product's design and saw an IC labeled with the prefix “UCC.” I paused and wondered, “Who's that?” and then I remembered: That prefix belonged to ICs from Unitrode, which was bought by Texas Instruments in 2000. You can still get many of those Unitrode parts from TI, and under their original part numbers.

It's not news that companies come and go. Sometimes they close up and disappear completely, or they are bought out by a competitor. Other times, they merge with a complementary vendor. In most cases, though, their parts live on, and are even used in new designs.

Why would a design engineer use parts like these in new designs, when their “ownership” is, shall we say, a little cloudy? I think it's because designers like to go with parts they have used before. There are several reasons for this: They understand the part reasonably well, they know which layouts work and which don't, they know about the associated passives, they know how to assess and test the part when needed, and they believe know they its idiosyncrasies (and all parts have them).

But there's more to it, from what I've seen. When designing a new product, every team has to decide where to take chances and where to play it safe. Most projects can only deal with “new and risky” in about 10-20 percent of the design; by re-using parts and subsections from previous designs, they can establish bounds on how many areas with unpleasant surprises they'll likely encounter.

It's especially the case when using analog and power parts, where new parts can certainly give you better performance, but older parts are often “good enough” to meet the objectives. Hey, they do the job, they do it well, and they do it without hassle — so why not use them again?

That's one of the many reasons you'll see older parts, which could be retired, still going on new BOMs, often from vendors who no longer are what they were. Fortunately, when companies acquire others (or take on their parts and related IP), they almost always keep the original prefix and part number. This makes a lot of sense, as the part is still inventoried under that designation, and is on various approved vendor lists that purchasing or the contract assembler uses.

Have you ever deliberately used an “older” part that you liked, rather than check for newer, perhaps better ones? Have you ever considered using a part with a prefix that is unusual, but from a credible vendor? Did you wonder how it got there? Are there any vendor names you haven't heard in a long time, but you still occasionally see through their parts — which live on?

22 comments on “Vendors Are Gone, but Their Prefixes Are Not

  1. Bill_Jaffa
    March 26, 2013

    I also recently saw the classic Burr-Brown BB prefix…some of their parts live forever (been part of TI for many years).

  2. DEREK.KOONCE
    March 26, 2013

    Siliconix is no more, now it is owned by Vishay. The 'Si' prefix is still in use for new products. Vishay, at one point, tried to kill the Siliconix brand, but it went back to continue using it due to the reputation of the 'Siliconix' brand. However, Vishay is slowly trying to cut the brand names out from its acquisitions. I am sure the component prefix will remain; similar that Burr-Brown and Unitrode still has prefixes with TI.

  3. Michael Dunn
    March 26, 2013

    A lot of old parts, adopted prefix or not, are still the best choice for a given task, even if you've never used them before. A lot aren't of course!

    This strikes a chord with me, fondly remembering some old companies, as well as some of the shocks that accompanied certain acquisitions – National being the obvious recent example, but Fairchild too, now independent again :-))), and remember the crazy GE/RCA/Harris/Intersil conflagration?

    And then there are the companies that have gone through more than one acquisition. Are Comlinear (which was bought by National) parts now to be found at TI?!?

    One day, I'll work up a family tree.

    Second sources with differing prefixes are another animal again. The TL431 for example seems to be made by everyone, and I recall a colleague once describing it generically with some prefix (and by some company) I'd never heard of. I didn't even realize what he was talking about till he showed me more details, whereupon I informed him it was a TL431, not a QMT431 or whatever…

  4. Brad Albing
    March 27, 2013

    Michael – I'd love to see that family tree. I can help w/ the GE/RCA/Harris portion – know those parts pretty well.

  5. Brad Albing
    March 27, 2013

    Some of those old BB parts were just the best for audio. Used those in an audio console I built years ago.

  6. Brad Albing
    March 27, 2013

    We used analog switches from Siliconix (and op-amps from Harris) back at Technicare – used in the sample-and-hold section of a pulse aquisition portion of a gamma camera.

  7. RedDerek
    March 27, 2013

    I remember that time of the GE/RCA/Harris/Intersil/etc name. Boy that was a mouthful to say.

    As for the family tree, I remember seeing one once. It was quite impressive because it included who started which semi company.

  8. Michael Dunn
    March 27, 2013

    I've seen one or two Electronics/Silicon Valley family trees too. My idea is more to do with documenting what companies got gobbled up by others, or changed their name.

    Anyone remember what Microchip used to be? 🙂

  9. RedDerek
    March 27, 2013

    A quick search revealed this Wiki page showing it was spun off from General Instruments. Which sounds right.

    http://en.wikipedia.org/wiki/Microchip_Technology

    Usually the best way to see the splits is to track down the founders. Wiki may offer suficient background to start with. Then just a few cross-checks to ensure accurate information.

    It would be interesting to see the combining process of companies as well. I would enjoy seeing the tree.

  10. Michael Dunn
    March 27, 2013

    > I would enjoy seeing the tree.

    It may turn up soon on Scope Junction

  11. ErinM
    March 27, 2013

    Old parts that are too good or popular to EOL are not the only reason you see those wonderful Burr Brown prefixes.  Just take a look at the newest products from TI – INA231, OPA4313, ADS1018, etc.  TI is still using the completely logical part numbering system they acquiared with Burr Brown.  I see their new battery management parts all start BQ (Benchmark), and there are even some UCC gate drivers released in the last six months.

  12. eafpres
    March 27, 2013

    I had the opposite experience; a large passives company acquired a connector company or two, and the parts were still available under the old brand; unfortunately the new parent moved and consolidated production and quality wasn't the same; took  a while to get them to own up to what had happened.  Names witheld to protect the guilty.

  13. Brad Albing
    March 27, 2013

    And I believe some of those UCC series parts are second-sourced, making them even more desireable to use in new designs or reworked old designs.

  14. Brad Albing
    March 27, 2013

    Reminds me of those charts showing rock bands – who came from which band, which band was formed from the ashes of another….

  15. Netcrawl
    March 28, 2013

    @eafras I believe acquisition or acquiring a small company by a bigger one is only part of a much larger strategy- to squash competition. Look at TI when it acquired National Semiconductors- what exactly they motivation here? build their portfolio? Its simple protect its core business-crush competition.  

  16. Brad Albing
    March 28, 2013

    Did not know that. Huh. Thought I knew all this family tree stuff.

  17. Brad Albing
    March 28, 2013

    Let's see… Iron Butterfly was a spinoff from Fairchild in the late 1960s. Then they broke up and formed Cream; Crosby, Stills, & Nash; and Intersil. I think that's right.

  18. Brad Albing
    March 28, 2013

    Now I'm intrigued. Was Tyco involved in any of this?

  19. Brad Albing
    March 28, 2013

    There is that, altho' it seems that TI is still carrying on all the parts in the NS portfolio. So you could look at this particular acquisition from a kinder perspective: TI just liked the NS portfolio and wanted to reap the profit potential from selling those parts.

  20. eafpres
    March 28, 2013

    @Brad–the areas of the Tyco family tree I lived through included (and I may have this wrong) M/A-Com–>AMP; AMP–>Tyco and rebranding Tyco to TE.  I can't quite remember of AMP got M/A-Com or if Tyco got both.

  21. Netcrawl
    March 28, 2013

    Iron Butterfly, a spinoff or came from Fairchild? I didn't know that. what happen to their lines? they core engineering team? The world are getting small here @brad, we're getting too many acquisitions-with two objective expansion and seek for a new market.  

  22. David Maciel Silva
    March 31, 2013

    It is common practice to maintain components used in other designers because it makes the project more reliable.

    A iten expensive in my view that was acquired by another company texas is the CI VFC320P for designers old he is still common, due to their characteristics of operation.

    http://www.ti.com/lit/ds/symlink/vfc320.pdf

    But it is an expensive iten approximately $ 26, and may be substituted for example by a microcontroller or even an AD7740 of Analog Devices.

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