Whats Wrong With Digikey, Ebay and The Pricing? - Page 1
Forum section: electronics / general

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 13, 2012, 09:59:27 am
content: while searching DDS chip AD9850... search in digikey gave me a bit of shock. the chip is priced USD24.49 (dont count shipping yet) herehttp://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=ad9850while earlier search in ebay showed very cheap price USD4.9 only each, here one eg...http://www.ebay.com.my/itm/10PCS-AD9850BRS-125-MHz-Complete-DDS-Synthesizer-NEW-/180774517453?pt=LH_DefaultDomain_0&hash=item2a17003acd.digikey chip alone is still far more expensive than the complete module kit USD8.5 herehttp://www.ebay.com.my/itm/NEW-AD9850-DDS-signal-generator-module-0-40MHz-/170682095715?pt=BI_Signal_Sources&hash=item27bd721863and both later links from China, as usual... free shipping! beauty!now (if i heard/read it correctly) dave said, digikey closes to manufacturer's pricing. and you may argue on single chip order. just look at minimum 1500qty order linked above, at USD15/chip is still far off. what the heck happened? is this chip is one case where digikey try to push more profit on? or the ebay china supply is cloned AD9850? like dave said... "anything cheaper than digikey is a cloned"? (again, if i translate it correctly)

author: Short Circuit
author_rank: Frequent Contributor
timestamp: March 13, 2012, 11:10:41 am
content: Something fishy with the Ebay offerings, probably build with recycled parts or an 'upgraded' lesser part. Check the ADI typical pricing and you'll see Digikey is not that far off.

author: T4P
author_rank: Super Contributor
timestamp: March 13, 2012, 01:22:15 pm
content: Hey Mech , didn't realize you are from Msia , you probably know where i am from alreadyBut yeah , the ebay offerings look a little real but it can really be fake or it really is a cloned chip .

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 13, 2012, 01:46:43 pm
content: problem is, all china sellers are consistent about the price. anyway, i'm in the process of ordering one, see if its a real fake.

author: sacherjj
author_rank: Frequent Contributor
timestamp: March 13, 2012, 03:23:03 pm
content: I've got an kit build AD9850 project and also just picked up one of these for < $8 US shipped to compare. It sounds like the filtering is pretty crap on the high frequencies. I'm thinking about getting another $20 kit minus the chip and relocate it from this $8 version (I paid ~$20 for my AD9850). Then I can compare legit with this one in the same circuit and see if the chip is good.Edit: Hmm. The kit I used was AD9851 based.http://midnightdesignsolutions.com/dds60/index.htmlLooks like the AD9850 is up to 125 MHz, and the AD9851 is up to 160 MHz.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 13, 2012, 04:52:52 pm
content: Quote from: sacherjj on March 13, 2012, 03:23:03 pmgood! i hope you'll come back with the report.edit: i believe the ad9850 and ad9851 will be similar or close in term of spectral purity, just higher frequency capablity on ad9851. i believe if the pins are compatible, you may place the ad9851 on the ad9850 board (with slower clock). but thats not certain, i'll have to check the datasheet first.in ebay listing, there's warning that above 20MHz, the sine will be distorted on this cheapo board, by how much, that one is to be found later.

author: OZ1LQB
author_rank: Regular Contributor
timestamp: March 13, 2012, 07:50:55 pm
content: Hi There..I have a handful of those 8.80$ AD9850 modules from Ebay and they work greatBUT for some reason the lowpass filter starts at 70Mhzi dont se it as bad because i use a bandpass anyway..go get them before the dealers find out what they are worth..73 de OZ1LQB / Claus

author: sacherjj
author_rank: Frequent Contributor
timestamp: March 13, 2012, 08:26:54 pm
content: Quote from: OZ1LQB on March 13, 2012, 07:50:55 pmI don't see how this can be the actual AD9850 chip. In 1.5k quantities at Digikey, these are $14. I can get an AD9850 off ebay, shipped for $4. Something sounds really hinky.Although I'm using these in the < 50 MHz arena, so maybe the knock off is legit in that range. Or possibly it is used in 100k quantities for something and the price really drops there. But I'm having trouble believing that. I guess if a knock offs works good enough, it isn't really a problem. Except for Analog Devices.I'm betting that these are chips that didn't meet the full 125 MHz specs for official AD9850. So they may work fine in the 10s of MHz, but can't really be sold as AD9850. Yield would be a driver for the price, correct?

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 13, 2012, 10:19:28 pm
content: Quoterejected chip? do they test all the chips out of production?

author: Psi
author_rank: Super Contributor
timestamp: March 13, 2012, 10:34:55 pm
content: Quote from: Mechatrommer on March 13, 2012, 10:19:28 pmexpensive chips they do yeah.Could easy be someone buying (or stealing) them out of the reject bin.However, most of the time companies don't throw away the rejects. They sell them as a lower spec version.Does a lower spec version of the AD9850 exist?Maybe the cheap china ones are actually those chips with the markings changed to appear like the fast spec version.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 13, 2012, 10:50:51 pm
content: Quote from: Psi on March 13, 2012, 10:34:55 pmor... they do makes them expensivewhatevernow those warning in ebay make more sense now.i suspect the testing must be fully automated in the line of production. since those reject chips in ebay also available in cut reel.

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 13, 2012, 11:21:25 pm
content: he sold 229 and had no complaints in the last 6 months anyway.

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 13, 2012, 11:23:27 pm
content: look at thishttp://www.aliexpress.com/product-fm/521843048-Wholesale-5pcs-lot-brand-new0-40MHz-2-Sine-Wave-DDS-Signal-Generator-Module-AD9850-free-shipping-wholesalers.html

author: OZ1LQB
author_rank: Regular Contributor
timestamp: March 14, 2012, 10:35:47 am
content: HI again.sacherjj i think that it is Chips that have ben removed from old pcb'sand the reason for me thinking that is that 1 or 2 years ago i bought some that was sold as usedchip's .but they work ok and are cheap so it is ok with me.if one dies in 1 or 2 years it doesn't matter because the were cheap ..sorry for bad spelling.73 De OZ1LQB / Claus

author: saturation
author_rank: Super Contributor
timestamp: March 14, 2012, 11:02:15 am
content: Chips prices on eBay can be very volatile; an authorized channel will sell at authorized prices and are traceable back to the manufacturer. So, its very likely lower priced ones are:counterfeitreclaimedold stocksurplus/liquidation/bankruptcyThe preferred ones are the last 2 as they are quality but simply old. The worst is the first, and the second intermediate because it depends on how the chips were reclaimed: if overheated and abused it could be damaged or fail prematurely when used. Either way, its not through an authorized channel so its a gamble: but the odds are 3/4 you'll get a decent part so its worth experimenting. When it arrives, performance test it.To put more odds in your favor buy from someone who has sold many of them and none of the buyers have complained.You can find similar price swings for most any chip, try the old 741 op amp or the 555 timer.

author: bombledmonk
author_rank: Regular Contributor
timestamp: March 15, 2012, 02:49:50 am
content: Most likely is counterfeit or reclaimed at that price per unit. ADI doesn't sell their reject products. They are very securely disposed of.

author: vis1-0n
author_rank: Contributor
timestamp: March 15, 2012, 06:25:38 am
content: What happens when a manufacturer makes say 9K of an item? Do they supply a reel of 90K each per part? 9100? Do you buy 9K priced at $8 each, or 10K @ $7.20? What happens when a product bombs or reaches saturation or delay in supply of other components leave you holding a few thousand or more IC's sitting on a shelf for a few months? IC's that need to be reflowed within so many hours for an expected QA yield of 99.5%?Why the primary suspicion to be counterfeit, reject or stolen? Despite the best efforts of purchasing, warehousing and logistics, surely there must be a market of surplus out there.

author: Psi
author_rank: Super Contributor
timestamp: March 15, 2012, 07:55:42 am
content: Quote from: vis1-0n on March 15, 2012, 06:25:38 amYeah, that does happen.but counterfeit, reject or stolen happens more often.

author: T4P
author_rank: Super Contributor
timestamp: March 15, 2012, 09:20:48 am
content: Quote from: Psi on March 15, 2012, 07:55:42 amI did realize some stuff i found that were made in china had been made from reject parts ...China eh ?

author: spacejunkie
author_rank: Newbie
timestamp: August 03, 2016, 03:13:24 pm
content: To all those saying the parts are fake or recycled from old equipment - Welcome to the supply chains of Shenzhen!The real volume business does not happen through Digikey at all, it happens through smaller trading companies in Hong Kong and Shenzhen. Digikey is very convenient but super overpriced for volume. Same is the case for Farnell, Avnet, RS Components etc. You would get much better deals on whole reels from traders in these places. 5x price reduction is the norm. For special purpose chips, if you buy it from the right vendor the difference can be more than 10x.Yes, fakes are a possibility but they are fake not as in dead slugs but pin and function equivalent parts. Many commonly needed parts have very good local (Chinese) equivalent chips which perform just as good as the original. I have personally found most traders to be honest. If you insist on a particular part from a particular manufacturer, they will give you the exact same part. Actually, they will ask you the full ordering code (including the last few characters in the part number which identify the minor variants of the part). Also, many traders are not engineers, so they take part numbers very seriously. They simply don't do approximate matches, like an engineer might. It is easy for experienced folks to tell fakes. It will not take long before they are caught. So no decent trader will make selling fakes his business strategy.The fully built modules on ebay etc. are a different story, there, they will label modules with equivalent chip with the name of the original chip so that their product appears in search results.

author: aholtzma
author_rank: Contributor
timestamp: August 03, 2016, 03:25:36 pm
content: The price you pay at Digi-key has little relation to the price you can get when you go through a disti or direct. With DK you are paying for the ability to buy 1 pc and have it on your desk the next morning. My rule of thumb is that you will pay a third of the full reel DK pricing through distribution. The exception is some companies (*cough* Qorvo) enforce uniform pricing across all distributors for volumes < 10k. Don't buy their parts

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 03:44:45 pm
content: Quote from: Mechatrommer on March 13, 2012, 10:19:28 pmThey are very likely rejects. Some devices don't pass final test and, in most cases, they are destroyed. It's better to destroy them than to have to replace them under warranty (plus angry customers). Sometimes, the rejects are 'stolen' and sold on the grey market.I buy just about all of my components from DigiKey. I don't buy parts from eBay and I haven't yet tried AliExpress or any of the others.Back around '88, I lived in Singapore (Pan Pacific Hotel, actually) and helped build a semiconductor plant on Science Park Drive. I made 13 trips to Malaysia during the year to dive at Pulau Aur (my favorite), Pulau Dayang and, of course, Pulau Tioman (great buffet). I had the best time of my life in Singapore and Malaysia and worked with some of the smartest engineers I have ever met.

author: rs20
author_rank: Super Contributor
timestamp: August 03, 2016, 04:56:32 pm
content: When studying this, remember: the null hypothesis can never be absolutely proven. In particular, you can prove that a particular chipisa reject or cloned part (e.g. transistor where the die is totally the wrong size), but you can never ever prove that a particular chip is genuine + not a reject. You can only placelower boundson how good a cloner would have to be, or how stringent the production testing is.Hence, "I tried a $8 AD9850 board and it worked fine" is essentially an irrelevant statement*. Maybe the chip's real, maybe your testing regime is inadequate. FTDI clones are a classic example of this; cursory examination of cloned chips before FTDIGate would have concluded that the chips work fine, until new evidence came to light and rejected this null hypothesis.And of course, the fact that the eBay chips might be a weird mix of fake, reject and genuine chips just muddies the water even further.* Irrelevant to answering the question "are these chips genuine?", but obviously totally relevant to the question "will the average hobbyist be happy with whatever turns up?".

author: TheAmmoniacal
author_rank: Unknown
timestamp: August 03, 2016, 05:17:24 pm
content: Who cares if they are genuine or not? If we assume they perform just as well?

author: rs20
author_rank: Super Contributor
timestamp: August 03, 2016, 06:34:26 pm
content: Quote from: TheAmmoniacal on August 03, 2016, 05:17:24 pmBecause that assumption might be wrong? Again, the same could be said about faked FTDI chips. What are the chances that people proclaiming that the chip works fine have verified that every single sentence and spec of the datasheet holds true?EDIT: Changed "cloned" to "faked" in a hopeless attempt to clarify the distinction between clones (perhaps defined as chips made and advertised by a second manufacturer to be a substitute) vs fakes (try to pass of as actually genuine).

author: System Error Message
author_rank: Frequent Contributor
timestamp: August 03, 2016, 07:02:44 pm
content: Genuine is important. Im not talking about part numbers but when it comes to parts essentially what you want is something that does what you want exactly so its not just the function but also the specs (such as tolerances, voltage limits, power consumption, etc).To me i dont care if something is genuine or a clone as long as it fits the functions i need and that it claims and has the actual specs aligned with claimed specs. So if i were to buy some chips even if they were a clone they must match all the functions of the original and an honest spec listed.

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 10:25:27 pm
content: Quote from: TheAmmoniacal on August 03, 2016, 05:17:24 pmBut likely they won't. I have enough problems getting my projects to work without having to deal with chips that are out of spec.

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 10:30:32 pm
content: Quote from: System Error Message on August 03, 2016, 07:02:44 pmAnd you have absolutely no way to test those specs. Maybe they work at room temperature, maybe they don't do so good when the temperature changes. Maybe the switching thresholds are right on, maybe they're not.The other game that used to be played by the foundaries, and probably still is, is to build all the chips the customer ordered plus a few million for themselves. One of the downsides to off-shoring manufacturing is that you can guarantee your chips will be competing with over-runs of your own chip.Probably the stuff on the grey market really is over-runs. They probably do meet all the specs. Why wouldn't they, they were made with the same process, on the same equipment, as the real deal.Or, they're rejects...

author: ebclr
author_rank: Super Contributor
timestamp: August 03, 2016, 10:34:33 pm
content: This fake genuine issue is handled by people that never put a foot on asia, There everything is possible, fake AND REAL, don't assume that all are fake and don't assume that all are real