Is this a fake or genuine MAX7219? - Page 1
Forum section: electronics / projects

author: circuitmaker9000
author_rank: Newbie
timestamp: November 21, 2022, 04:07:46 am
content: I have recently put together an LED alarm clock kit (GC-1006) from a reputable kit supplier and it seems the MAX7219 has stopped working. Looking closer at the part that came with the kit, I noticed something slightly off about how it is marked. On the first line the name of the manufacturer reads "MAXIMI". The other markings appear normal to me with the part number on the second line: "MAX7219CNG" and the date code on the third line: "+1918". (The Maxim Integrated parts I have seen in the past have been consistently labeled as "MAXIM", this is the first part I have seen labeled as "MAXIMI").Anyone else have a similar problem with this part or this kit? What does the front of your MAX7219 look like? A picture of mine (PDIP-24) is attached.

author: MikeK
author_rank: Super Contributor
timestamp: November 21, 2022, 04:36:10 am
content: Maxim would not misspell their own name. lol

author: bdunham7
author_rank: Super Contributor
timestamp: November 21, 2022, 04:52:16 am
content: I think this is a picture of a real one.

author: srb1954
author_rank: Super Contributor
timestamp: November 21, 2022, 06:24:50 am
content: Quote from: MikeK on November 21, 2022, 04:36:10 amProbably a cloned part designed to deceive those who don't look too closely at the package.A bit like the rip-off phone chargers that appear to be genuine Apple products except for the label saying "Abble".

author: wraper
author_rank: Unknown
timestamp: November 21, 2022, 07:29:18 am
content: Fake, Chinese make clones which mostly work besides some quirks. However they have much smaller silicon die, thus low load capacity and reliability.

author: amyk
author_rank: Super Contributor
timestamp: November 22, 2022, 03:08:38 am
content: Logo looks more like AAAXIAAI to me

author: coromonadalix
author_rank: Super Contributor
timestamp: November 22, 2022, 10:44:11 am
content: and you see the laser traces on your maximi

author: tszaboo
author_rank: Super Contributor
timestamp: November 22, 2022, 10:57:18 am
content: " Actually, our brand name is IWIXVW and it's written upside down on the logo"

author: circuitmaker9000
author_rank: Newbie
timestamp: November 24, 2022, 07:52:11 am
content: I heard back from Maxim Integrated customer support and they confirm that the MAXIMI part that came with my GC-1006 clock kit does not come from Maxim Integrated production.

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 24, 2022, 08:09:20 am
content: So much for the 'reputed kit supplier'.

author: circuitmaker9000
author_rank: Newbie
timestamp: November 24, 2022, 08:17:25 am
content: I have found at least one other GC-1006 clock kit builder who may have also received a counterfeit MAX7219, shown in the picture below. In this case, the company name appears to be spelled correctly but the pins don't conform to the datasheet, in particular: the end pins are "half pins" while these pins are shown as "full-pins" on the Maxim datasheet. That picture was taken in January 2020, so it appears that the kit producer, if confirmed, has been sending out counterfeit MAX7219 for at least 2 and 3/4 years. What a disappointment.Unfortunately, I think it spells doom for this kit producer.Photo Credit:at time 7:44

author: james_s
author_rank: Super Contributor
timestamp: November 24, 2022, 08:19:48 am
content: Almost all of the MAX7219 chips out there are counterfeit, the real ones cost an arm & a leg. I've used the knockoffs many times and never had any trouble with them. I just wish they'd market them under their own brand instead of trying to pass them off as genuine.

author: circuitmaker9000
author_rank: Newbie
timestamp: November 24, 2022, 08:45:11 am
content: Quote from: james_s on November 24, 2022, 08:19:48 amI guess it depends on what level of reliability you are aiming for. I came across this post which compares the die area of a real and fake MAX7219:https://forum.arduino.cc/t/maxim-7219-real-and-fake-compared/226823The fake one has a die area about 1/4 the real one. This makes for much higher thermal stress on the fake part, which can not possibly operate reliably at the maximum current rating specified by the Maxim datasheet. I also doubt the fake one received qualification testing up to the level that Maxim Integrated would have done.I have access to a failure analysis lab so, once I get mine decapped, I will post a picture of the "MAXIMI" die here.Maxim also gave me a list of authorized distributors for the real MAX7219, so real ones are available to purchase, but I have to agree they are on the pricey side, even at quantities of 1000.

author: MikeK
author_rank: Super Contributor
timestamp: November 24, 2022, 03:21:27 pm
content: Quote from: circuitmaker9000 on November 24, 2022, 08:17:25 amI like to hear more from others on this. I just checked a bunch of chips within reach on my desk: all of the PIC's, except for the 20-pin PIC16F1769, have half pins on the ends and all were sourced from Digi-Key. The 24-pin MAX127, sourced from Maxim, has full pins on the ends. So I'm now curious what half pins on the ends means, if anything.

author: ledtester
author_rank: Super Contributor
timestamp: November 24, 2022, 03:46:30 pm
content: I just ran across the page at the Heathkit site:https://shop.heathkit.com/shop/product/display-board-update-for-most-reliable-clocktm-for-early-pre-2017-models-gca-1006-5-30?category=34QuoteFran's PCBs have the part numbers: 85-7097-3 and 85-7097-5 which can be seen at around 34:30 in this video:https://youtu.be/DUj4GPavx2Y?t=34m30sSo apparently the "current display chip" is the MAX7219 clone.which begs the question... what display chip were they using pre-2017?

author: james_s
author_rank: Super Contributor
timestamp: November 24, 2022, 07:09:21 pm
content: Quote from: circuitmaker9000 on November 24, 2022, 08:45:11 amI wouldn't automatically equate die area and reliability. Is it made using the same process? The natural progression of ICs has been ever smaller and smaller dies.

author: circuitmaker9000
author_rank: Newbie
timestamp: November 24, 2022, 11:54:43 pm
content: Quote from: james_s on November 24, 2022, 07:09:21 pmIf for example this was a case of one made by Intel and the other by AMD, then that argument could be valid. But in this case we are talking about a known company, Maxim Integrated, versus an unknown counterfeiter. Show me the qualification report for the counterfeit part which shows that it matches the performance limits set by the MAX7219 from Maxim Integrated. But why would you trust such a report from an unknown company that engages in fraud (i.e. tries to pass off their product for the real thing)?The MAX7219 also combines power and logic on a single chip. For example if the MAX7219 uses linear current regulation, large power dissipation will be present and near the operating limits the genuine Maxim part (having larger area and therefore lower junction to case thermal resistance) would operate cooler and thus more reliably. Essentially the Maxim datasheet is no longer valid for the counterfeit part.

author: james_s
author_rank: Super Contributor
timestamp: November 25, 2022, 06:50:39 am
content: Quote from: circuitmaker9000 on November 24, 2022, 11:54:43 pmI didn't say the counterfeit part matches the performance limits of the genuine MAX7219. I said that I wouldn't automatically assume that it does not based solely on the die area. That is not the same thing.

author: circuitmaker9000
author_rank: Newbie
timestamp: November 25, 2022, 08:40:05 am
content: Quote from: james_s on November 25, 2022, 06:50:39 amThis thread is about the MAX7219 so I have to disagree: for a linear regulator, the current capability is pretty much proportional to die area for a given package. The MAX7219 contains 8 linear current regulators internally. A 4x smaller (by area) version of the MAX7219 would have current limits roughly 4x lower versus the full-size one. To give the smaller area one the same part number would give the false indication that it would handle the same current level as the full-size version.