Price Difference between Digikey and Aliexpress - Page 1
Forum section: electronics / general

author: aimthiazz
author_rank: Newbie
timestamp: May 30, 2017, 02:00:57 pm
content: Hi,I'm planning to design a simple buck converter using LM2596. I was estimating the Bill of Material cost using Digikey and Aliexpress and I noticed that there is a huge cost difference between them.Digikey :https://www.digikey.com/product-detail/en/texas-instruments/LM2596S-ADJ-NOPB/LM2596S-ADJ-NOPB-ND/363705Cost : $5.41 per ICAliexpress :https://goo.gl/4sTsKP(I have shortened the URL)Cost : $7 for 50 IC, which roughly comes around $0.14 per ICI understand that the Aliexpress vendor might be selling counterfeit IC's which are prone to high defective rates. But the cost difference between them is huge. Any Idea on why I should prefer Digikey over Aliexpress? Any Input / Insight will be helpful. TIAP.S. Cost specified are in USDAlso I'm relatively new to this forum, I'm not sure whether this is the right channel to post my question. Let me know if I need to post it in different channel.

author: MagicSmoker
author_rank: Super Contributor
timestamp: May 30, 2017, 02:20:23 pm
content: Yeah, $7/50 means those are almost certainly counterfeit or reject parts, but for that price why not try them out?I, personally, won't use ICs from Alibaba or Aliexpress, but that is more because I value my time and having to rework a board to remove a dodgy IC that didn't meet its specs is way more costly than the IC itself.

author: mdszy
author_rank: Unknown
timestamp: May 30, 2017, 02:22:47 pm
content: Probably most certainly fake/bad chips. I almost always order from DigiKey, never had any problems and while it might cost more, stuff gets to me in 2-3 days and I know it's good, quality stuff.

author: Monkeh
author_rank: Super Contributor
timestamp: May 30, 2017, 02:28:41 pm
content: There are substantially cheaper, faster switchers available, which will not only save you money on the IC, but on the inductor and board area as well. Upgrade to 21st century parts and save money at the same time!

author: JPortici
author_rank: Super Contributor
timestamp: May 30, 2017, 02:42:36 pm
content: probably they are NOT LM2596i've read somewhere that all those cheap regulators marked to have a LM2596 actually uses another regulator which is functionally compatible albeit being far worse in specs

author: jonovid
author_rank: Super Contributor
timestamp: May 30, 2017, 02:47:23 pm
content: how many units?Saving of just 1.59 USD not worth the customer backlash. but for the hobbyist, its more fun and games

author: anishkgt
author_rank: Frequent Contributor
timestamp: May 30, 2017, 02:50:47 pm
content: Well Lets put it this way if you intent to sell your design Digi-Key would be more reliable as you don't want your customers buying stuff that blows up after a week or so. After all,your selling 'Trust' also. If your just a hobbiest and have enough time to play around. Then give AliExpress a try.Sent from my iPhone using Tapatalk

author: rea5245
author_rank: Frequent Contributor
timestamp: May 30, 2017, 02:54:38 pm
content: If you buy the ones from AliExpress, let us know if they're any good.- Bob

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 30, 2017, 02:54:46 pm
content: I second the opinions of previous posters.If these chips are for your own personal use, and/or they are not used on a critical application, then you can purchase the lower cost devices.However,if you are planning the sale of these units,the cost of replacing the defective components and the bad customer feelings you will create is simply not worth the cost differential.I speak from experience. I have gotten badly burned before by counterfeit devices.

author: anishkgt
author_rank: Frequent Contributor
timestamp: May 30, 2017, 02:59:44 pm
content: Myself having said that, I had bought 100 ATmega from ebay, 100 diodes, 100 LM7805, 100 H11AA1 etc. but I knew what I was buying. The 7805 was Chinese but worked so far. So it's all about luck.Basically small stuffs like resistors are ok as long as the tolerance of these is not a factor to you.Sent from my iPhone using Tapatalk

author: Kjelt
author_rank: Super Contributor
timestamp: May 30, 2017, 03:04:56 pm
content: You answered your own question:Digikey: proven TI 2596Aliexpress: unknown chinese brand mislabeled 2596 who knows what it is and will do.So the question is how much is it going to cost you if the regulator dies and the input voltage will be on the output frying the product ?I have read a lot of sad stories about the cheap fake 2596s enough to only use them at 750mA max.Same with the so called HV versions.Good luck with your lotery.

author: anishkgt
author_rank: Frequent Contributor
timestamp: May 30, 2017, 03:06:09 pm
content: Some ic's like the 7805 would have CN marked on them instead of ON or ST. Comparatively ebay is more reliable than AliExpress because buyer feedback is very much valued by eBay and the seller too. So what you can do is mail them via eBay messages and enquirer if it is genuine and latter if 'the item is not as described' you are cover by 'eBay buyer protection' where you can either opt for a replacement or a refund.Sent from my iPhone using Tapatalk

author: Muxr
author_rank: Super Contributor
timestamp: May 30, 2017, 03:07:13 pm
content: Only stuff I order on Aliexpress are either unique tabaoo contraptions. hard to find parts, or expensive salvaged pieces I am willing to take a chance on (for instance, mini solar panels I'll order from Ali). But for for everything else I actually use Mouser.. I often find they tend to have better prices for the majority of parts I am looking for, the price brakes on quantity orders are well laid out as well.. they just seem to cater more towards the hobbyist or small run guys. If you need a specialty part and the largest selection Digikey is still the best place, although occasionally I've found new parts on Mouser that haven't made it to digikey yet.If I am desperate for a part (for a repair) I will also use octopart.com metasearch and ebay as well.

author: aimthiazz
author_rank: Newbie
timestamp: May 30, 2017, 04:07:55 pm
content: Thank you all for your responses. I guess I should experiment it for the sake of science. Will post my observation later. 😀

author: Kjelt
author_rank: Super Contributor
timestamp: May 30, 2017, 04:11:18 pm
content: First test: switching frequency original is much higher than the fakesSecond Test: input voltage 30V drop down to 5V and 2,5A current, stopwatch when it fails.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 30, 2017, 04:57:50 pm
content: There are cheaper options from reputable suppliers via Digikey -cheak out Richtek and Alpha Omega Semiconductor for example

author: wraper
author_rank: Unknown
timestamp: May 30, 2017, 05:01:00 pm
content: Quote from: MagicSmoker on May 30, 2017, 02:20:23 pmBecause they work at much lower frequency and when they will fail, very likely will destroy the load by overvoltage as well.

author: DerekG
author_rank: Frequent Contributor
timestamp: May 30, 2017, 05:18:44 pm
content: Quote from: aimthiazz on May 30, 2017, 02:00:57 pmDigikey have built their business by only purchasing from 1st tier suppliers (normally direct from the manufacturer themselves).The counterfeits are normally very good with their "remarking" but the differences can normally/often/sometimes be spotted under the microscope.You can purchase both the OEM part from Digikey & the cheap parts from Aliexpress & have a good look yourself.In this case there is a huge difference in price, however excess/no longer used 1st tier stock does turn up on Aliexpress. As a "rough rule" these "real OEM" parts are priced at somewhere between 50% & 70% of the volume OEM price. In these cases the vendor will normally state the actual manufacturer of the parts ie On Semi, Fairchild etc & you can ask (& often receive) for a copy of the invoice from the 1st tier supplier. Often these invoices are 3 to 10 years old which indicates how long these parts have been held in stock.We are currently doing a stock take of our excess stock & will list volume numbers of micros such as some old ST6 micros, PIC16F72, PICF73 on Aliexpress shortly.Our stores are however based in Australia

author: Kjelt
author_rank: Super Contributor
timestamp: May 30, 2017, 09:37:00 pm
content: ST6 really? I worked with ST7s in 2004 so these chips must be over a decade old?

author: thm_w
author_rank: Super Contributor
timestamp: May 30, 2017, 10:02:35 pm
content: For sure some of those aliexpress LM2596 are genuine, the hard part is figuring out which ones.btw if anyone is buying TI parts, just buy direct from TI, their prices are lower than Digikey and they use Digikey to send out the parts:https://store.ti.com/LM2596S-ADJ/NOPB.aspxAs Mike says AOS make good cheap switchers, should be much more compact than the LM2596, if you are designing one into a product.Or you could even get something like this and solder it onto your board:https://www.aliexpress.com/item/5-pcs-Mini-360-DC-DC-Buck-Converter-Step-Down-Module-Ultra-Small-Power-Supply-Module/32412017021.html(assuming specs are within your requirement).

author: DerekG
author_rank: Frequent Contributor
timestamp: May 31, 2017, 12:08:26 am
content: Quote from: Kjelt on May 30, 2017, 09:37:00 pmCorrect: circa 1998-2004 (they sold side by side against the ST7 for many years).We should have cleaned out our stores much earlier!Whilst we have been mainly using PIC16 parts for the past 15 years, we are now moving back to the ST8 parts from ST Microelectronics for our lower end products as Microchip can no longer compete.Take a look at the pricing for an STM8 part with 8K Flash & 1K RAM - both available with 16 I/O (US$0.36) & 28 I/O (US$0.52) (Digikey pricing, if you order from Arrow etc your would save a further 10% on these prices).https://www.digikey.com/product-detail/en/stmicroelectronics/STM8S003F3P6TR/STM8S003F3P6TR-ND/4357536https://www.digikey.com/product-detail/en/stmicroelectronics/STM8S003K3T6CTR/STM8S003K3T6CTR-ND/3455602

author: krho
author_rank: Regular Contributor
timestamp: May 31, 2017, 04:48:29 am
content: There is also stm32l0 which in some configurations comes to ~1$@1000pcs and has half the consumption of stm8s003

author: Smallsmt
author_rank: Frequent Contributor
timestamp: May 31, 2017, 04:51:13 am
content: Semiconductor suppliers sell parts to big production runs like automotive components at very low prices.Most of the microcontrollers costs below 1 usd we pay normally 4 to 5 times more sometimes 10x.Some parts on Aliexpress are pre owned or second hand parts so take care.Fake parts are possible to0 but if you check the electrical parameters against a reference part it should be safe to use.

author: DerekG
author_rank: Frequent Contributor
timestamp: May 31, 2017, 04:56:27 am
content: Quote from: krho on May 31, 2017, 04:48:29 amYes, ST Microelectronics have been sharpening their pencils these past couple of years with their "Value Line" micros, in both 8 bit & 32 bit.Atmel AVR's (the under dog) always looked to be bit better value than Microchip ............ but all that is changing now with STM competing hard in the same space, often coming in at half (or one-third) the cost of a similar PIC part.

author: Kjelt
author_rank: Super Contributor
timestamp: May 31, 2017, 05:25:42 am
content: Quote from: DerekG on May 31, 2017, 12:08:26 amBeen working since 2008 to 2011 with those chips when they were only prototypesnice chips for small products but they lack the processing power of the arm 32 bits that use less power.

author: janoc
author_rank: Super Contributor
timestamp: May 31, 2017, 08:58:37 am
content: Even if the AliExpress chips were genuine, you can't really compare it like this. Don't forget the US costs of labor, electricity, shipping by UPS, customer service, warranty, etc. that you pay in the Digikey price. That stuff isn't for free and shows up in the price of the product.The AliExpress vendor could well be a small mom&pop store operating from a shack somewhere in Shenzen with minimal expenses, shipping by the cheapest and slowest postal service. And good luck getting customer service or warranty claim from them - most I had to deal with were genuinely trying to help and to fix any problems but it is far from the same level of service as Digikey (or another major vendor). By buying from a large distributor you are literally also paying for having someone available on the phone that you can scream at should they screw up. That is important for business clients (who are the majority of their customers).Also LM2596 are fairly old parts, running at low frequencies, thus requiring massive inductors. I would probably look for a newer part for a new design.

author: Kean
author_rank: Unknown
timestamp: May 31, 2017, 02:38:09 pm
content: Very good chance they are fake LM2596 - operationally similar, but poor quality. I have some boards from ebay & AliExpress using this chip (very common on ebay, I think these were the ones with a voltage display). They worked fine for a few days before basically failing in the worst possible way, putting the 24V input straight out onto the 5V rail. They were running nowhere near their full rating, or getting particularly warm.

author: krho
author_rank: Regular Contributor
timestamp: June 01, 2017, 04:57:51 am
content: Yelling at someone from digikey/mouser doesn't help you when the fuck up and order the chip which has a lead time of 14 weeks in the wrong package. (Yes, we provided the correct one.) And then you have to wait another 14weeks to get the chips. And you fail to launch the product at the right time because of that.

author: dmills
author_rank: Super Contributor
timestamp: June 01, 2017, 10:34:24 am
content: That sort of fuck up on a preprod run is what the grey market is for.Note that there are grey market vendors and grey market vendors, use someone respectable (Usually means paying MORE then list) and you have an excellent chance the parts are genuine, you are paying for the lack of a 14 week leadtime.My personal hate on is for distributors who have their own house numbered products (Farnell Multicomp, looking at you), especially when some prat designs in something like a Multicomp SD card socket that then goes on 20 weeks leadtime, because you are NOT going to find that part anywhere else.Regards, Dan.

author: janoc
author_rank: Super Contributor
timestamp: June 01, 2017, 01:53:47 pm
content: Quote from: Kean on May 31, 2017, 02:38:09 pmYikes!I have two or three such modules too, only without displays. I have planned to use them with some microcontroller to get some "brains" for my Roomba long time ago. I guess I better build that dummy load that I am putting off for months and test them first.However, it is very common that the Ali/eBay ads will advertise these as 3-5A modules (the maximum current from the datasheet) - except that module has often no or very inadequate heatsinking and then people wonder ... That likely haven't been your case but it is another very common issue with these devices.

author: Kjelt
author_rank: Super Contributor
timestamp: June 01, 2017, 04:21:41 pm
content: Add a fuse and crowbar circuit @6V to the output and you can sleep again

author: ebclr
author_rank: Super Contributor
timestamp: June 01, 2017, 04:40:59 pm
content: Finally a decent point of view"Even if the AliExpress chips were genuine, you can't really compare it like this. Don't forget the US costs of labor, electricity, shipping by UPS, customer service, warranty, etc. that you pay in the Digikey price. That stuff isn't for free and shows up in the price of the product."It's obvious that Digikey labor, cost is an order of magnitude higher than any China company, Also in USA a company need to expand a huge money on attorneys due to how people love to sue others there, and this is why China components are cheaper.The fools like to point as is fake, but this isn't what really what happens, is very easy to find real and original component cheaper in China. Of course, the ones extra cheap( I mean less than average in a China) have a probability of having sort kind of problems, China component volume is 2 orders of magnitude higher than any other country, and is quite easy to find high-quality components on sale for less than high volume factories price for an immense sea of reasons other than being fake.

author: edavid
author_rank: Super Contributor
timestamp: June 01, 2017, 05:23:31 pm
content: The "LM2596" parts that you commonly find on AliExpress are remarked Chinese ICs that are similar to the LM2576.They are probably perfectly good parts, if you had the real datasheet.If you want to buy from AliExpress, I suggest sticking with Chinese parts such as XL4015 - you have a much better chance of getting what you expect.

author: ebclr
author_rank: Super Contributor
timestamp: June 01, 2017, 06:15:42 pm
content: Do you have any statistically valid evidence of your claim?

author: janoc
author_rank: Super Contributor
timestamp: June 01, 2017, 07:10:31 pm
content: Quote from: Kjelt on June 01, 2017, 04:21:41 pmOr just ditch the junkers.

author: Habropoda
author_rank: Regular Contributor
timestamp: June 01, 2017, 07:30:03 pm
content: Quote from: edavid on June 01, 2017, 05:23:31 pmThe LM2596 modules I have purchased in the last couple of years run at about half of the 150khz they are supposed to run at and have poor ripple, so they are remarked chips for sure. Modules I purchased years ago run at 150k and have the expected ripple.Many products seem to have gotten worse over time. Recently I got some 18ga wire, marked as such, that was half that. I also got some of those so called Dupont ribbon cables but I could pick them up with a magnet.I'm buying more stuff from Digikey these days.

author: Kjelt
author_rank: Super Contributor
timestamp: June 01, 2017, 08:40:37 pm
content: I must say I used quite a bit of those fake modules but at limited current like 750mA or so.

author: wraper
author_rank: Unknown
timestamp: June 01, 2017, 10:38:08 pm
content: Quote from: dmills on June 01, 2017, 10:34:24 amThe only thing you need is figuring out original part number which is quiet easy in most cases.

author: Kean
author_rank: Unknown
timestamp: June 02, 2017, 10:21:39 am
content: Quote from: janoc on June 01, 2017, 01:53:47 pmI was running them at less than 1A - powering a Raspberry Pi and some custom sensors and controls, all from a DIN rail PSU.Actually I just checked, and I was mistaken - the one that never failed was actually the one with the LED V/I display. The ones without displays were the ones that needed a crowbar, and not of the electronic typeAnyway, I may have just got a bad/dodgy batch, but I'm extra cautious now with cheap stuff I get from AliExpress or ebay. I don't care much if an OLED display or I2C sensor breakout I'm using to prototype with fails, but I really don't like valuable stuff going up in smoke. In this case I was just planning to use them during prototyping on the bench. I replaced them with my own custom DIN rail DC/DC converter modules, as most of the ones on the market are silly expensive.

author: Psi
author_rank: Super Contributor
timestamp: June 02, 2017, 12:06:43 pm
content: Usually, if you look at all the aliexpress sellers who are offering the IC you're after and order by price you can see where the price jumps and where they are more likely to be good chips.

author: zeqing
author_rank: Regular Contributor
timestamp: August 10, 2017, 03:47:53 am
content: As a PCBA producer for more than 5 yeas, i suggestion is :1. for prototyping, use the digikey/mouser parts....your time values than the IC, or even you will cry when some fake IC used ;2. check the IC from aliexpress by yourself before the mass production. as my experence , >95% is OK, at least functional.for no-so-big price difference it is because the seller on aliexpress is distributors but not resellers. the difference can be up to 50%. for even larger price difference, maybe fake IC.

author: jmelson
author_rank: Super Contributor
timestamp: August 10, 2017, 04:07:31 am
content: Quote from: aimthiazz on May 30, 2017, 02:00:57 pmI've had several grey market experiences. One from a long time ago was a supposedly reputable US distributor, I bought a reel of op-amps. It took 25 per board. About 50% of them failed immediately on power up. Going back over them, I noticed there were 3 different date codes on the same tape. I called the manufacturer, and they guaranteed that there could never be different date codes on one reel. So, the parts were apparently salvaged after somebody installed a few thousand backwards and the boards failed testing.I had blank boards left when some Xilinx CPLDs went end of life, so I ordered them from China. About 20% of them would not program, or failed in more spectacular ways. So, I don't know if these were off scrapped wafers, counterfeits, or whatever. But, I was doing final test on the chips!So, I avoid buying anything from China unless I am totally up against the wall. You can read on various newsgroups, etc. about bad experiences with buying parts from China. Lots of people have gotten total junk, empty packages, completely wrong chip inside, 60 W power transistors with a 1/4 W die inside, so it checks OK on a transistor tester but blows instantly in the intended circuit. Stuff like that.Jon

author: DerekG
author_rank: Frequent Contributor
timestamp: August 10, 2017, 06:06:56 am
content: Quote from: jmelson on August 10, 2017, 04:07:31 amYes, my sentiments also Jon.The only time we look at Chinese component purchase is if we can deal directly with the manufacturer in China themselves. This means that we are obviously not buying named brands like Microchip, ST Microelectronics etc.