Semiconductor Marketing Tips (Through the Use of Misleading Specs) - Page 1
Forum section: electronics / general

author: niconiconi
author_rank: Frequent Contributor
timestamp: April 11, 2022, 11:25:11 pm
content: 1. Make sure to use a different test methodology or standard to specify the performance of your part in the datasheet, so it's impossible for designers to make a direct comparison against your competitors.2. When your device has a good parameter, make sure the first page of the datasheet shows its performance tested by a method that gives the best-looking numbers. Bury the other numbers tested under more realistic settings in the least visible page in the Electrical Specification section.3. When one parameter of your component is far from ideal, never even list that in the datasheet, just pretend it doesn't exist!4. If your device performance starts degrading seriously beyond a point, just cut off the X-axis early in your graphs before that happens. For example, if the frequency response is really bad beyond 500 MHz, just stop at 450 MHz, so people will never notice this deficiency in the datasheet!5. Always advertise the best theoretical performance, even if it's not practical or literally impossible to achieve in real-world applications. For example, assume input impedance is perfectly matched to a non-standard value. Or, when the package limits the maximum MOSFET current to 100 A RMS, still say your MOSFET can handle 200 A in large boldface font!6. Always boast your device using its "Typical" specs and claim it's the latest and greatest thing ever. What? Guaranteed worst-case performance is 30% lower than "Typical"? You're just unlucky! Better luck next time in your next silicon lottery!7. When one of your device parameters has small unwanted variations, make sure they're unreadable from the datasheet charts. With a scale large enough or logarithmic, only the extreme ends are distinguishable, everything looks like a straight line! Remember the saying of the great seismologist Charles F. Richter, "logarithmic plots are a device of the devil."8. Remember to list all prices of your parts on their product pages to increase sales. But DO NOT list them in the parametric search list, so it's impossible for designers to compare your part's price/performance ratio, and hopefully will pick a more expensive part by accident.After finished writing this, I later learned there's even a special word for these marketing practices, calledspecsmanship.QuoteAnyone has more to add?

author: dbctronic
author_rank: Regular Contributor
timestamp: April 12, 2022, 12:19:54 am
content: Claim that the part is 'equivalent to' a part it just plain isn't.I've seen a Chinese transistor datasheet claiming that their transistor is a replacement for the 2N2222. Casual inspection of the operating parameters shows that several are just plain NOT 2N2222 equivalent, at all--the minimum hFE is 20, not 35! It's a general purpose NPN signal transistor, and that's about it. 'Replacement' my sore butt.I didn't bother to check whether the pinout is the same...

author: niconiconi
author_rank: Frequent Contributor
timestamp: April 12, 2022, 02:26:20 am
content: Quote from: dbctronic on April 12, 2022, 12:19:54 amAn example I've seen. Nexperia has a "PMEG" series of low-Vf Schottky diode, useful for squeezing the last half percent of efficiency out of a power supply. The PMEG3020ER for example, has 365 mV typical, 420 mV max at 25 degrees. Meanwhile, a quick LCSC search finds another Taiwanese company, Shikues, sells the same part. But the datasheet says the Vf is 500 mV typical, 550 mV max.Yes, definitely beware.But speaking of your 2N2222 example, I think these classic parts are all JEDEC-registered standard parts. If I get it right, the JEDEC's requirement for 2N2222 only says the DC current gain at 1 mA should be 50, and nothing more... So, if this part meets that bare-minimum spec, it's a fair game to make the claim... But if not, then it would be not just a case of "marketing" but plain dishonesty.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: April 12, 2022, 02:33:55 am
content: Why bother measuring anything? Just plagiarize someone else's datasheet!

author: SpacedCowboy
author_rank: Frequent Contributor
timestamp: April 12, 2022, 02:48:02 am
content: The most egregious example of this I ever saw was Silicon Image - I was writing some firmware to translate MHL to HDMI using one of their chips. It. Did. Not. Work.I called up the rep, and he told me, quite serenely that the public data sheet was wrong, and he'd send over the correct one under NDA. That man was lucky not to be in my immediate vicinity.I couldn't do much about it then, time pressure was a thing, but I told my boss I would never work with their chips again, and if he wanted a project with their chips in it, to get someone else to work on it. To my knowledge we never bought one of their chips thereafter.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 12, 2022, 02:49:15 am
content: Quote from: niconiconi on April 11, 2022, 11:25:11 pmIf it's sold as a 450MHz part, what's the problem? Those who rely on how a part behaves "overclocked" should not be surprised if a different batch doesn't work as well as they hoped.Those repairing old equipment (especially audio) sometimes experience the opposite problem: the modern parts perform way better at high frequencies than the original causing the circuit to oscillate.

author: niconiconi
author_rank: Frequent Contributor
timestamp: April 12, 2022, 03:24:47 am
content: Quote from: NiHaoMike on April 12, 2022, 02:49:15 amIf the part starts behaving in a rather unexpected manner just beyond a point, the datasheet better to get that documented as a warning. For a hypothetical example, an amplifier can either gradually roll off, or start peaking wildly, which can be a problem even if you're not trying to drive it off the limit deliberately. Some vendors clearly show that in the datasheet for the benefits of their users, others do not...What I wanted to say is that, as users, don't always assume vendors are all that friendly.

author: Berni
author_rank: Super Contributor
timestamp: April 12, 2022, 05:38:38 am
content: Oh yes certainly NEVER take numbers directly from the first page of a datasheet.That first page of a datasheet seams to always pass trough the marketing department in order to dress it up with cherry picked numbers and bold claims.Then again there are also lazy datasheets that just forget to give you a important piece of information. Like what is the thermal pad under the chip connected to? Is it NC? Is it GND? Or is it AGND? No idea, the datasheet never mentions it, so take your guess and run with it.At one point i had a datasheet for a color OLED display way back that i already built a PCB for and was trying to figure out why the colors are all wonky. Eventually i found a comment in the initialization source code example that says Vee must be -4.1VNowhere in the datasheet it mentions the display even needs a negative supply voltage so i was connecting it to GND.Afterwards i looked trough the datasheet with a fine tooth comb afterwards and i could not find that info in the whole pdf

author: Circlotron
author_rank: Super Contributor
timestamp: April 12, 2022, 05:39:25 am
content: Specify maximum power dissipation when the device is directly metal bonded to an infinite heatsink at 25 deg C.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 12, 2022, 06:31:59 am
content: Quote from: Circlotron on April 12, 2022, 05:39:25 amThat would give a lower value than currently typical standard thatfor power parts assumes a case temperature of 25 C, no matter how yout get and if if that mean immersion in cold water.The power ratings with SMD parts is a funny thing: it is usially valid with a near infinite copper plane and yet some parts advertise high power rating and small par size. Some power resistors assume a rather high temperature - some THT parts up to 350 C, so better don't use leaded solder with these.

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 12, 2022, 08:31:33 am
content: Tests for analog semiconductors are fishy but power devices specifications (IGBTs, Mosfets...) take the cake

author: Ian.M
author_rank: Super Contributor
timestamp: April 12, 2022, 09:54:38 am
content: Leave out the DC line on any SOA graph, because even on an actively cooled cooled copper block maintaining Tjof 25° C it blows up at a very small percentage of its front page ratings.

author: niconiconi
author_rank: Frequent Contributor
timestamp: June 07, 2022, 07:36:27 am
content: Want to make your product to stand out from the competition with the highest ratings? No problem. Just lower your stress-test standard, say from 300% to 150%, then you can put a higher number on its labels. Don't forget to ask the customers to de-rate them again in the fine prints.

author: PartialDischarge
author_rank: Super Contributor
timestamp: June 07, 2022, 08:05:17 am
content: Quote from: niconiconi on June 07, 2022, 07:36:27 amWho cares, has *anyone* seen a warranty claim on a semiconductor product made reality?

author: rsjsouza
author_rank: Super Contributor
timestamp: June 07, 2022, 08:22:52 am
content: Quote from: niconiconi on April 12, 2022, 03:24:47 amWell, that does not make much sense to me: where would one stop pushing parameters outside of the designed range to try to get a more complete picture of the behaviour in these conditions? Imagine if, in your example, the part was pushed up to 10% above its designed spec (495MHz)? Out of spec parts are anyone's game. A 50A transistor driving 55A blows up? Should this be published?

author: niconiconi
author_rank: Frequent Contributor
timestamp: June 07, 2022, 09:14:14 am
content: Quote from: rsjsouza on June 07, 2022, 08:22:52 amI only said, from the perspective of a customer, it would be "better", or to be precise, "nice to have", I did not say a vendor is "required" to do that.Of course it's all subjective, and there's no technical obligation for a vendor to publish typical out-of-spec curves (even when it is published, it's usually "typical" and not parts of the guaranteed specs). But then, there's also no obligation for a vendor to write any application note, design checklist, FAQ, product selection guides, etc., either. But still, in practice, if a vendor is selling some parts, all of these (including putting a typical out-of-spec curves in datasheets) are often done (though not always) in goodwill to make their components easier to use by their customers, reduce the numbers of oversights and unexpected "gotchas", and in turn, ultimately helping the vendor to sell more parts in the future.Back to the hypothetical amplifier example. An amplifier can either gradually roll off, or start peaking wildly outside their rated bandwidth. As a vendor there's absolutely no obligation to put any additional information in the datasheet in a peaking amplifier. If unsuspecting users selected that amplifier - thinking that the bandwidth is sufficient with no intention to exceed its spec - in a time-domain application, but later gets horrible overshoots and ringings in the step response, of course it's all their faults for this oversight. On the other hand, in this situation, the vendor may as well include the peaking part in the "typical" frequency response curve (or do something similar, such as putting a warning in an application note) as both a friendly gesture to their customer and a way to reduce the unnecessary workloads of their field application engineers, so it saves everyone's time - which is a pretty common thing do do.What I wanted to say is just that - don't get too accustomed with it, don't always assume the documentation provided by the vendors is all written like world-class manufacturers like Linear or TI, who are often friendly enough to do the extra works outside their obligations - especially when the part is made by a smaller vendor.I don't think there's anything controversial with that statement.Quote from: rsjsouza on June 07, 2022, 08:22:52 amIf this is a common oversight often encountered in real-world applications (e.g. from common but unexpected transients in a particular topology in an application), and if the vendor happens to be known in the industry for providing good customer support and documentation, and if the vendor is still motivated to maintain this reputation, then yes, it should be published. Or rather, it would be nice to get that published.I remember seeing a Linear application note, talking about how switching transients by slow diode turn-on time can exceed the absolute maximum of the DC-DC chip's rating in a rather surprising manner in some situations, and that can be detrimental to the lifetime of the chip. The note was completed with test circuits, scope traces, and references to primary sources. Did Linear have any obligation to write and publish this App Note. Of course not. But it was also what differentiated Linear as one of the most successful analog vendors from the rest of the industry.