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Why Can’t I Find the Parts That I Need?

I wanted to procure a few low-power class-D audio amplifiers for a project I was working on. I needed a two-channel amplifier, a few Watts per channel, 4- or 8-Ω load (TBD later), and supply voltage 5V to 10V. I knew there were probably more devices available that were capable of operating at 5V than at 10V since the IC process that works at low voltage is less expensive, so it's used more often.

For this exploration of devices, let's pick on NXP, which is where all these screen shots came from. It could just as well be one of the other guys. I happened to pick NXP first — so just my two cents worth of frustration taken out on it. Let's start on its home page:

OK, this looks promising. There's a line item on the left that says amplifiers. Great — I'll probably be able to look at a chart that will give a quick overview. Then I'll be able to drill down and have my device selected with just a few clicks. I'll be able to see what is available and probably get an idea of packages and a ballpark price.

So I'll just click on amplifiers; and I go to this:

That looks good. Now I just pick the audio products as opposed to CATV or op-amp devices.

That takes me to a more detailed selection. Still looks promising. No reason to worry because there's what I want — class-D — and it looks as if there are 16 versions of such devices. I'll click on that choice.

And I get to read a nice overview of the devices. Hmm… not much especially useful technical info here except that they make devices from 0.4W up to a couple hundred Watts. Well, good; should be parts in my power range. Must be the next tab on that chart that I want, where it says “Products.” Yes, please, I would like some products. I believe that's way I came to this site, as I recall.

So I'll just click on the tab and…

Uh-oh. So apparently NXP has some very muscular class-D amps (75W, 150W, 210W, etc.) and a few other devices that they just mention in passing. I say that because there is no information except “class-D amplifier” — which I sort of would have guessed, what with this being the portion of the NXP site that promotes class-D amplifiers. So I guess I am obliged to click on any line items of interest (they are hyperlinks) to learn more. That could be a tedious, dead-end process, so, so, so…

But wait! There is another tab that I overlooked: “Parametric search.” That should let me zero in on just what I wanted (regarding supply voltage and output power) at the beginning of this odyssey. I'll just click the tab and…

Oh, crap… what the… Another chart containing no useful info at all.

So, let's summarize what we've learned:

Nothing.

Now, that's not enirely fair, because I've seen this elsewhere. I really don't want to pick on NXP. There are other sites that have apparently been created by people who lack a clear understanding of how engineers want to get information. Please post your comments and let me know your experiences in this regard. Perhaps, if some of the folks at the head-offices of some of our favorite semiconductor companies see this, they will make some changes.

9 comments on “Why Can’t I Find the Parts That I Need?

  1. eafpres
    February 25, 2013

    Hi Brad–I can't see anything but the 1st screenshot, but I get the gist of your note. I think distributor sites like DigiKey, Mouser, TTI might make selection easier.  They often do a better job than manufacturers of loading parts into a multi-supplier drill down so you can hone in on specs and find one or more parts that meet your needs.

  2. Michael Dunn
    February 25, 2013

    There's an Add Column button. Perhaps all the useful parametric columns are hidden for some reason, and you must manually add them…??

    But I agree – some mfr's web sites are bad/unusable beyond belief. I'm amazed they remain in business.

    As a starting point, or for non-critical design work, using e.g. DigiKey as a primary source for component selection is certainly attractive. Though I've found their site has become unwieldy. Whoever's in charge of summarizing component info into their database has gone way too far in making differentiations between minor differences. Hmm, do I want an opamp with max +16.3/-17.8V supplies, or +18.5/-15.8V ones…?

    Also, units are not sorted correctly, such that one ends up with tables sorted: 0.1ppb, 0.1ppm, 0.1%, 0.2ppb, 0.2ppm…etc…

  3. Brad Albing
    February 25, 2013

    Tried that. Nope – no help.

    I'll take a closer look at Digikey. That leads me to think that I willl probably find solutions to my design problems, but the solution will not be specific to any one manufacturer. So good for me, but bad for NXP or whomever I might have initially thought of when I thought, Gee, I need a low power class-D amplifier.

  4. Brad Albing
    February 25, 2013

    Sorry about those images. Our picture server was having a brain cramp for a little while.

    Yes, I'm starting to think that checking w/ the Distis is the way to go.

  5. David Maciel Silva
    February 25, 2013

    As our friend said Eafpress, looking at a site like digikey or mouser, when there is something specific, when I say do not worry about the manufacturer is a good option.

    Since when have the part number I usually use this site:

    http://www.findchips.com/

    This site returns me where I can purchase the items, key suppliers and quantity in stock.

  6. Michael Dunn
    February 25, 2013

    Yeah, they've certainly screwed up that Class-D section. You may have just got unlucky. I tried MOSFETs, and the parametric table was well populated.

  7. eafpres
    February 26, 2013

    Hi Brad–for fun (!) I tried searching on DigiKey's site.  Used “Class D Amplifier”; then chose “Linear Amplifiers – Audio” and you get a nice multi-filter page.  Choose NXP then filter to Class D and Stereo and you have a page with linked datasheets.  I got about the same thing on Mouser.

    I think this is where distribution shines.  The large IC guys focus a lot on OEM accounts and projects, leaving stuff like this to distribution.  They don't really sell from their websites. 

  8. Brad Albing
    February 26, 2013

    Valid point about “they don't sell from their websites.” Sadly, that may leave them in danger of not selling in general, since one never knows for sure where a sale may originate. Oh well, their loss.

  9. Brad Albing
    March 27, 2013

    Oddly, NXP never dropped me a note to speak to this issue.

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