On Counterfeit USB-serial Chips

USB to serial port adapters are gadgets that we have a love/hate relationship. We love that we can add serial port to a new PC, but we hate that many of those adapters do not feel reliable in use. Counterfeit copies of USB to serial ICs have caused headaches for users and manufacurers. And it seems that in the future they cause even more headaches. Counterfeit electronics components are a serious problem to electronics and chip manufacurers. It seems that two big USB-serial converter chip manufacturers have come up with their own fight against counterfeits, which is could be viewed both good and bad. It is bad news if your hardware has counterfeit ICs in it.

Prolific (PL2303) adapter is an common solution about USB to Serial port adapters. Note: How to not get scammed with Prolific (PL2303) USB – Serial adapters forum discussion tells that the latest Prolific driver has strict chip identification code in it: If the Prolific chip in your adapter is a fake copy, the driver does not work with it: “This device cannot start. (Code 10)” error. Lots of cheap product claiming to have PL2303 do not work with new driver, but they could work better with old driver (if you want to gamble that option). And usually those fake copies work quite well with Linux.

Prolific has an warning about the fake chips in their website too. The fakes are quite common in the cheap translucent USB to serial converters. Common problems are the drivers refuse to work (code 10) or they are just not reliable. That does not feel not very friendly if you happen to own such hardware. But that’s correct and healthy corporate cooperation. Prolific needs to protect them self’s from all those counterfeit parts. 1) Looses money from those. 2) Their work it must be patented, and so they have to protect it.

Another well known USB-serial converter IC manufacturer is FTDI. Their FT232RL chip is an extremely common chip used to add a USB serial port to projects, builds, and products. The FTDI FT232 chip is found in thousands of electronic baubles, from Arduinos to test equipment, and more than a few bits of consumer electronics. Because is it commonly used, there are counterfeits of them also (probably one of the most cloned pieces of silicon on Earth). FT232RL: Real Or Fake? article shows picture of real and fake FT232RL chip. In this case the fake chip is really just a microcontroller made protocol compatable with the addition of a mask ROM. It’s very hard to tell the difference between the real and fake.

Watch That Windows Update: FTDI Drivers Are Killing Fake Chips article tells that thanks to a recent Windows update, all those fake FTDI chips are at risk of being bricked (“soft brick“). If fake FTDI chip is plugged into a machine running the newest FTDI driver something unexpected happens: the latest driver bricks the fake chips, rendering them inoperable with any computer. So , all those fake FTDI chips are at risk of being bricked.

Reports of problems with FTDI chips surfaced early this month, with an explanation of the behavior showing up in an EEVblog forum thread. Watch That Windows Update: FTDI Drivers Are Killing Fake Chips article mentions a work-around to fix those bricked devices: use FT232 config tool from the FTDI website on a WinXP or Linux box, change the PID of the fake chip, and never using the new driver on a modern Windows system.



  1. Tomi Engdahl says:

    I had some bad experience on my Prolific USB serial port adapter and Windows 8.
    None of my Prolific adapers worked :-(

    My USB To RS232/TTL PL2303HX Cable Adapter
    Did not work with Windows 8 drivers (Worked well with Windows Vista and 7).
    Also older PL2303 based adapter did not work :-(

    Web page http://www.prolific.com.tw/us/showproduct.aspx?p_id=225&pcid=41 says:
    Windows 8/8.1 are NOT supported in PL-2303HXA and PL-2303X EOL chip versions.

  2. Tomi Engdahl says:

    FTDI Screws Up, Backs Down

    A few days ago we learned chip maker FTDI was doing some rather shady things with a new driver released on Windows Update. The new driver worked perfectly for real FTDI chips, but for counterfeit chips – and there are a lot of them – the USB PID was set to 0, rendering them inoperable with any computer. Now, a few days later, we know exactly what happened, and FTDI is backing down; the driver has been removed from Windows Update, and an updated driver will be released next week. A PC won’t be able to communicate with a counterfeit chip with the new driver, but at least it won’t soft-brick the chip.

    Microsoft has since released a statement and rolled back two versions of the FTDI driver to prevent counterfeit chips from being bricked. The affected versions of the FTDI driver are 2.11.0 and 2.12.0, released on August 26, 2014. The latest version of the driver that does not have this chip bricking functionality is, released on January 27th.

    [marcan] disassembled the FTDI driver and found the source of the brick and some clever coding. The coding exploits differences found in the silicon of counterfeit chips compared to the legit ones.


  3. Tomi Engdahl says:

    Windows 8/8.1 are NOT supported in PL-2303HXA and PL-2303X (EOL chip versions) according to http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=225&pcid=41

    This is pretty annuing bercause I have hardware that uses those specific chips.

    I was justr wondering why they don’t want to support them anymore?
    Is it because they are not technically good (I think they were OK), they did not see point in spending little bit of money on supporting them also (should not be much work because they had drivers for older Windows – the users will get annoyed of this lack of support which can cost more on reputation) or is it because most of the clone ICs were emulating those specific chip types (and they can’t tell which is genuine and which is copy..)? I don’t know.

  4. Tomi Engdahl says:

    When the biggerst most known USB-serial converter IC makers seem to piss users, the question would it be better to stop using their products and look something that is less annoying…

    In initial tests it seems that poducts that use CH340 (http://wch-ic.com/product/usb/ch340.asp) seem to work pretty well without annouging issues. I have for example some Arduino compatible products that use CH340 IC. The initial feling on this is positive.

  5. Tomi Engdahl says:

    From http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=155&pcid=41

    Warning Notice:

    It is confirmed that counterfeit (fake) PL-2303HX Rev A USB to Serial Controller ICs using Prolific’s trademark logo and device drivers were being sold in the China market. Counterfeit IC products show exactly the same outside chip markings but generally are of poor quality and causes driver compatibility issues. We issue this warning to all our customers and consumers to avoid confusion and false purchase. Only buy from Prolific authorized distributors.

    PL-2303HX Rev A (or PL-2303HXA) also has been discontinued (EOL) since October 2012 and does not support Windows 8 onwards. Prolific advises users to purchase cables/adapters with PL2303HXD (HX Rev D) or PL2303TA chip.

  6. Tomi Engdahl says:

    Prolific PL2303: The Cheapest and now declared fake

    Prolific i guess this name is familiar with most of my friends who always peek into the device manager, yes this is the most common USB Controller used in mobile phone, cameras and lot more things, it may be the oldest usb interface chip maker.

    I was searching for a USB to TTL converter for my project needs, nobody prefer to use a IC with inbuilt usb transreceiver which creates extra coding overhead. The first choice is FT232 or FT232Rl from FTDI , it is the most recent and supports every OS and available everywhere, although cost is little high. I guess its most reliable than any other chips.

    Second one is TUSB1105 /1106/3410 , moderate cost, drivers available for windows only, used in mobile phone and scientific instruments

    Silicon lab CP2102, same as TI’s chip they have support for windows and in built driver in linux kernel (written by opensource contributor, not supported by silicon lab)

    CH341 from Nanjing Qinheng Electronics used in BAFO-810 USB Serial Converter

    PL2303 from Prolific we have already discussd about it, this is the cheapest

    FT232RL only chip costs INR 300/-
    where PL2303 fully assembled device with connectors and lamination Costs INR 200/- only

    Why is it selling so cheap ?
    Ans: Some chinease companies has replicated it, and to stop them Prolific modified the driver(inbuilt in windows 7 and 8) to reject the replicated designs, throw a error code 10, now the user can’t find which is original and which is fake on a online shopping site, so nobody purchasing these, and they have to sell :P

  7. Tomi Engdahl says:

    FTDI yanks chip-bricking driver from Windows Update, vows to fight on
    Next driver to battle fake chips with ‘non-invasive’ methods

    Chipmaker FTDI has pulled a driver from Windows Update that could brick devices containing knockoff versions of its USB-to-serial bridge chips, but says it won’t back down on its aggressive anti-counterfeiting stance.

    Earlier this week, hackers from various hardware forums began noticing that FTDI’s latest driver would set a USB device’s USB product ID to 0 if it contained a fake version of one of FTDI’s chips. Once zeroed, neither Windows, OS X, nor Linux would recognize the device anymore, rendering it useless.

    Naturally, owners of devices containing the counterfeit chips were less than pleased.

    “As you are probably aware, the semiconductor industry is increasingly blighted by the issue of counterfeit chips and all semiconductor vendors are taking measures to protect their IP and the investment they make in developing innovative new technology,” FTDI CEO Fred Dart said in a blog post on Friday. “FTDI will continue to follow an active approach to deterring the counterfeiting of our devices, in order to ensure that our customers receive genuine FTDI product.”

    Dart said FTDI is working on a new version of its driver that will still reject non-genuine chips but will “do so in a non-invasive way that means that there is no risk of end user’s hardware being directly affected.”

  8. Tomi Engdahl says:

    Fake Chip Furor Challenges Counterfeiters

    It’s not often that a driver upgrade creates a social media storm, particularly with USB chips. But the Glasgow chip designer FTDI faced a storm of criticism after a new driver was released for its FT232R USB-to-UART bridge chip.

    The problem was not with FTDI’s chip; it was with counterfeit devices that people had bought over the Internet thinking they were genuine FTDI parts. The driver did not work with fake chips, effectively “bricking” people’s USB interfaces.

    “A month ago, we did an update to our driver, and a side effect is that counterfeit devices are putting themselves into a noncompatible state,” Gordon Lunn, global customer engineer support manager at FTDI, told us. “The same API calls go out to all devices, whether genuine or nongenuine. The fake ones are not as compatible as you would expect. We have had no backlash from any of our major customers, but we have temporarily suspended the driver from being downloaded. We will investigate what is happening in the current driver and, in the fullness of time, reinstate the driver download, and if there’s something we need to alter in the driver, we will do that.”

    “Ultimately, we are challenging the counterfeiters,” Lunn said. “We want to maintain the quality and supply chain. Our distributors all have an investment in FTDI, which we are trying to protect, and we test our parts so that we produce the best output with genuine devices.”

    The company doesn’t want its products to be compatible with “nongenuine devices,” he said.

  9. Tomi Engdahl says:

    Finding a Cheaper USB to Serial Chips

    FTDI-gate wasn’t great for anybody, and now with hardware hobbyists and technological tinkerers moving away from the most popular USB to serial adapter, some other chip has to fill the void. The cheapest USB to serial chip on the market appears to be the CH340G, available for 20-40 cents apiece from the usual retailers.

    The CH340 series of chips do exactly what you would expect them to do: a full-speed USB device that emulates a standard serial interface, with speeds from 50bps to 2Mpbs. The chip supports 5V and 3.3V, and all the weird modem lines are supported. This chip even has an IrDA mode

    USB to serial chip CH340
    English DataSheet

  10. Tomi Engdahl says:

    I thought the Prolific series of chips nicely filled the bottom and somewhat ropey end of the market? Saying that though, most PL chips are cloanes and their drivers block off ones of them.

    Source: Comment at http://hackaday.com/2014/12/02/finding-a-cheaper-usb-to-serial-chips/

  11. Tomi Engdahl says:

    Why use a dedicated USB to serial chip when you can use an AVR to do the same task in software?

    Because it is cheaper?

    Source: Comments at http://hackaday.com/2014/12/02/finding-a-cheaper-usb-to-serial-chips/

  12. Tomi Engdahl says:

    A big disadvantage for this chip (CH340) is not having the drivers in windows update. Having to install drivers for something simple sucks.

    Source: Comment at http://hackaday.com/2014/12/02/finding-a-cheaper-usb-to-serial-chips/

  13. Tomi Engdahl says:

    Unbricking A Counterfeit FTDI Chip

    If you haven’t been paying attention, FTDI, makers of one of the most popular USB to UART chips out there, really screwed up last October. They released a driver to Microsoft that would brick unauthorized clones of their chip by setting the USB PID pair to zero. This renders the chip unusable by any computer.

    Luckily, there are ways to reprogram these chips. [Mark Lord] released a set of tools that will reset the USB PID. This unbricks the chip, fixing whatever device it’s attached to.


  14. Tomi Engdahl says:

    No Windows Drivers? Boot up a Linux VM!

    [Voltagex] was fed up with BSODs on his Windows machine due to a buggy PL2303 USB/serial device driver. The Linux PL2303 driver worked just fine, though.

    [Voltagex] went for the obvious workaround: create a tiny Linux distro in a virtual machine, route the USB device over to the VM where the drivers work, and then Netcat the result back to Windows.

    Using Buildroot, a Linux system cross-compilation tool, he got the size of the VM down to a 32Mb memory footprint which runs comfortably on even a small laptop. And everything you need to replicate the VM is posted up on Github.

    Is this a ridiculous workaround? Yes indeed. But when you’ve got a string of tools like that, or you just want an excuse to learn them, why not?

    “Fixing” a buggy Windows driver with a Virtual Machine

  15. Tomi Engdahl says:

    Another USB to serial IC:


    CP210x USB to UART Bridge VCP Drivers

    The CP210x USB to UART Bridge Virtual COM Port (VCP) drivers are required for device operation as a Virtual COM Port to facilitate host communication with CP210x products.

  16. Tomi Engdahl says:

    FTDI Drivers Break Fake Chips, Again

    Just over a year ago, FTDI, manufacturers of the most popular USB to serial conversion chip on the market, released an update to their drivers that bricked FTDI clones. Copies of FTDI chips abound in the world of cheap consumer electronics, and if you’ve bought an Arduino for $3 from a random online seller from China, you probably have one of these fake chips somewhere in your personal stash of electronics.

    After a year, we have the latest update to FTDI gate. Instead of bricking fake chips, the latest FTDI drivers will inject garbage data into a circuit. Connecting a fake FTDI serial chip to a computer running the latest Windows driver will output “NON GENUINE DEVICE FOUND!”, an undocumented functionality that may break some products.

    FTDI gate mk. 1 merely bricked fake and clone chips, rendering them inoperable. Because fakes and clones of these chips are extremely common in the supply chain, and because it’s very difficult to both tell them apart and ensure you’re getting genuine chips, this driver update had the possibility to break any device using one of these chips. Cooler heads eventually prevailed, FTDI backed down from their ‘intentional bricking’ stance, and Microsoft removed the driver responsible with a Windows update. Still, the potential for medical and industrial devices to fail because of a random driver update was very real.

    The newest functionality to the FTDI driver released through a Windows update merely injects unwanted but predictable data into the serial stream. Having a device spit out “NON GENUINE DEVICE FOUND!” won’t necessarily break a device, but it is an undocumented feature that could cause some devices to behave oddly.

    Topic: FTDIgate 2.0?

  17. Tomi Engdahl says:

    Comments from http://www.eevblog.com/forum/microcontrollers/ftdi-gate-2-0/

    FTDIgate 2.0?

    Edit: Confirmed to be the standard behavior of the FTDI driver for a year now, but now comes back up because of the new driver beeing spread out by windows update. For a fix look at #msg854401

    Okay… connecting RX to TX actually reads back “NON GENUINE DEVICE FOUND!”. A brief google search tells me that that’s actually not new.

    Because they’re tired of fakes on the market?

    Sure, as if I would buy genuine FTDI chips now :-DD
    All new devices I have use the CH340G. Sending random characters on the RS232 interface may cause really bad things to existing products and the buyer often had no chance to know that he bought a fake chip… |O But that all had been discussed a year ago.

    So, just a warning for you all, be aware of the new FTDI driver coming with windows update!

    I have no problem using FTDI, or buying anything that uses FTDI. Don’t buy knockoff crap and it’s not a problem. On the off-chance you do end up getting a knockoff chip in a legitimate product, talk to the manufacturer so they can RMA it and get their supply lines sorted out.

    I’ve tried older drivers 2.10.00 and 2.08.30, both give me “NON GENUINE DEVICE FOUND!”. Can these chips now be permanently bricked??

    I think the fake chips are fine. But since FTDI cannot brick the counterfeit chips anymore they just send some garbage (“NON GENUINE DEVICE FOUND!”) over their data endpoints. Doing so won’t brick the chips but they will still render the products using them useless. I guess only the Windows driver can do this scam because for Linux, the source code for FTDI driver should be available and such behavior won’t be tolerated into a Linux kernel driver. Can you try these boards on a Linux machine?

    I have no problem using FTDI, or buying anything that uses FTDI. Don’t buy knockoff crap and it’s not a problem. On the off-chance you do end up getting a knockoff chip in a legitimate product, talk to the manufacturer so they can RMA it and get their supply lines sorted out.

    That’s great if you are a patient end-user consumer with a non-critical application and no particular time schedule.
    And buying something expensive enough to come with the bare minimum of “Customer Service”.

    Okay, got it back working ;)
    If you manually select an older driver, like 2.08.30, you have to change the driver not only on the obvious “USB Serial Port (COMx)” (ftdiport.inf) but also the corresponding “USB Serial Converter” (ftdibus.inf) listed under “USB-Controller” in the device manager. After changing BOTH to 2.08.30, the chip works fine again. It is easy to see if you list the devices by connection.

    Guess with the new driver being rolled out by windows update at the moment that might be a trap for lots of us, not having had to deal with this pain in the ass stuff for more than a year now.

  18. Tomi Engdahl says:

    Adafruit Interviews The CEO Of FTDI

    When it comes to electronic hobbyists and EEs, there is no company that deserves a few raised eyebrows than FTDI. They made their name with USB converter chips, namely USB to serial chips that are still very popular today. So popular, in fact, that clones of these chips are frequently found in the $2 Arduinos from China, and other very low-cost devices. A little more than a year ago, a few clever people noticed FTDI drivers were bricking these counterfeit chips by setting the USB PID to 0000. The Internet reacted to this move and FTDI quickly backed down from that position. The Windows driver was fixed, for about a year until the same shenanigans were found again.

    Adafruit recently sat down with [Fred Dart], CEO of FTDI, giving us all the first facts and figures that aren’t from people frustrated with Windows’ automatically updated drivers. The most interesting information from [Fred Dart] is how FTDI first found these counterfeit chips, what FTDI chips are being counterfeited, and how many different companies are copying these chips.

    The company first realized they were being cloned when they couldn’t reproduce results of a Chinese-made ‘FTDI’ USB to RS232 cable that behaved strangely. A sample of the cables were shipped to FTDI and after inspecting the chip inside, FTDI found it was a clone with a significantly different architecture than a genuine chip.

    Exclusive interview with Fred Dart – CEO of FTDI @FTDIChip #FTDI @adafruit

  19. Tomi Engdahl says:

    Fixing Fake FTDIs

    If you know where to go on the Internet, you can pick up an FTDI USB to Serial adapter for one dollar and sixty-seven cents, with free shipping worldwide. The chip on this board is an FTDI FT232RL, and costs about two dollars in quantity. This means the chips on the cheap adapters are counterfeit. While you can buy a USB to serial adapter with a legitimate chip, [Syonyk] found a cheaper solution: buy the counterfeit adapters, a few genuine chips, and rework the PCB.

    Why is [Syonyk] replacing non-genuine chips with the real FTDI?
    The best reason is FTDIgate Mk. 1
    FTDIgate Mk. 2


    Or just don’t bother and buy a board/cable with another UART to USB chip – like the Chinese CH340, Microchip’s MCP2200 or similar.

    Reworking the counterfeit boards does not make any economical sense, IMO. If you really need the features of the FTDI chip (like the bitbang mode) then buy a board with genuine chip. If you don’t (and most people don’t), then just go for one of the above and be done with it – and you will still save money. They are equally well (or better) supported than the old FTDI chip that doesn’t use a standard CDC class driver.

    Fixing Fake FTDI FT232RL Adapters (SSOP-28 rework with an iron)

    The chips aren’t fake in the “Oh, the factory ran an extra few shifts off the books” sense. They’re fake in the “The fake chips are actually a microcontroller programmed to behave (almost) exactly like the FT232R” sense – and, they do a pretty good job at low speeds!

    Zeptobars did some analysis and demonstrated that the fake chips are completely different under the hood, and then of course FTDI messed with their drivers to either brick the fake chips or insert garbage data if you’re using one on Windows.

    Fake FT232R Identification

    FT232R chips have a unique ID burned into them – at least, the legitimate ones do. The fakes have an ID, but it’s hardly unique – the same ID will be reused extensively before a new ROM is spun. This makes identifying the fakes easy – buy a few, and if they all have the same name, they’re fake!

    Another way is to search for your chip’s serial number. A50285BI is a common fake one, and if you see any hits for your serial number on Google, it’s almost certainly a fake.

    I set out to replace my fake chips with legitimate chips. I wanted reliable 3M baud communication, and also hands on experience with surface mount rework (I’ve not done it before). Since the adapters are cheap and the legitimate chips are cheap-ish ($4.50/ea in small quantities), it seemed like a good project to start out with.

  20. Tomi Engdahl says:

    Hands On With The SHACamp 2017 Badge

    Through the final months of 2016 and into 2017 then the first badge prototypes came together.

    The replacement for their socket with the plastic protrusions turned out to overlap the edge of the board enough to touch the next panelised board during pick-and-place, and PCBWay, their manufacturer and one of their sponsors, pulled off some heroic mass reworking to deliver the goods. All seemed well, and the boards were manufactured and despatched from China to Europe.

    When the completed boards arrived, they worked perfectly. Or at least, they seemed to. It soon became apparent that for about half the boards though there was an unexpected problem in that a switch from USB to battery power would reset the ESP32. This was eventually traced to the Silicon Labs USB to serial chip, and a fix had to be concocted.

    It’s a Fake!

    The Silicon Labs part had been chosen due to ease of software drivers across all platforms compared to familiar alternatives such as the FTDI chip. Silicon Labs themselves had provided some sponsorship in the form of a significant number of the chips, but that had not been sufficient for the whole production run.

    The remainder had to be sourced in China, and as some of you are probably guessing at this point, the chips from China turned out to be fakes.

    Even then, they weren’t bad fakes, they performed as you’d expect the original to, but their designer had made a crucial omission in leaving out a protection diode on the USB lines. The resulting spike on disconnection was thus enough to reset the ESP32, spelling potential disaster for the project.

  21. Tomi Engdahl says:

    Beware of Counterfeit Max232 from China

    I just received a shipment of some RS232 to TTL converters from China exactly like the ones here.

    Out of the whole shipment NONE worked.

    Upon further investigation, I replaced the “max232″ with a real one, and it worked every time. I did this for a few others and they also worked.

    The chip itself has markings on it “MAX232 CSE +1027″.
    They were a good deal. I should have known it was too good to be true.

    Many fake manufacturers from China are doing that! Sparkfun also reported similar ancient with ATMega328: SparkFun Electronics

    I suspect that many of the electronic components sold by Chinese eBay sellers are counterfeit. The prices are just way too good on many of these parts. China is the land of reverse engineering, and I’ll bet a good percentage of these parts, while they might work well enough, are not genuine.

    I know of a few guys who got burned buying a large QTY of avr’s from china (one guy bought 500 pcs!). They lost alot of $$.
    In my situation, these items quickly appeared, immediately lots of ebay sellers flooded the marketplace.

  22. Tomi Engdahl says:

    RS-232 troubleshooting: fake chips

    RS-232 is still the most popular interface for balances and scales. It is often described as “simple”, however, when things don’t work as expected, finding the cause can be difficult.

    When you’ve tried everything and still can’t reliably communicate with your scale via RS-232, there’s a chance a fake chip may be the cause.

    Just a few weeks ago, the thought of encountering counterfeit ICs in digital scales had not crossed my mind. Thanks to FTDI’s recent attempt to “brick” counterfeits via Windows Update, fake chips are now a hot topic on the web. While I don’t agree with the way FTDI tried to punish the end user, I wish the controversy had occurred a few weeks earlier. This would have saved me a lot of time.

    Back then I was doing the final QC for several scales which were about to be shipped to a customer. The last item on my checklist was “bidirectional communication using RS-232”

    Eventually, I arrived at the conclusion that something was very wrong with the MAX232CPE+ chips, which are responsible for converting TTL signals to RS-232 levels. After doing some research on the internet*, I started to suspect those chips were counterfeit. It seemed like a far-fetched idea** at the time, but I still desoldered them, took a few pictures and sent them to Maxim Integrated.

    Fake MAX232CPE+ and MAX232EPE+
    Counterfeit MAX232CPE+

    Fake, fake and fake.

    Thankfully, I received a reply in less than two hours:

    “Yes these parts are counterfeit, they do not match markings of lots we manufactured.”

    Now extremely suspicious of all MAX232s***, I disassembled a few more scales from 4 different suppliers. 3 contained ICs belonging to the MAX232 family, so I sent the pictures to Maxim Integrated, too. In addition to the chips used by the scale manufacturer which had prompted me to start this investigation, one chip used by another manufacturer was also flagged as counterfeit.

    To be fair, my sample size is too small to draw meaningful conclusions regarding the entire weighing industry. However, if you’re in the business of making weighing instruments and were blissfully unaware of this issue, I hope this article serves as a wake-up call.

  23. Tomi Engdahl says:

    Decapsulation Reveals Fake Chips

    A while back, [heypete] needed to get a GPS timing receiver talking to a Raspberry Pi. The receiver only spoke RS-232, and the Pi is TTL level serial. [Pete] picked up a few RS-232 to TTL conversion boards from an online vendor in China. These boards were supposedly based on the Max3232, a wonderchip that converts the TTL serial to the positive and negative voltages of RS-232 serial. The converters worked fine for a few weeks, before failing, passing a bunch of current, and overheating.

    On Mouser and Digikey, the Max3232 costs about $1.80 in quantity one, and shipping is extra. You can pick up a ‘Max3232 converter board’ from the usual online marketplaces for seventy five cents with free shipping. Of course the Chinese version is fake. [Pete] had some nitric acid, and decided to compare the die of the real and fake Max3232s.

    Investigating Fake MAX3232 TTL-to-RS-232 Chips

    A while back I needed to interface a GPS timing receiver that only has an RS-232 serial connection with one of my Raspberry Pis. The Pi only supports TTL-level serial and only tolerates voltages between 0-3.3V its the UART pins.

    Enter the MAX3232, a chip from Maxim Integrated that converts between RS-232 and TTL serial with supply voltages from 3.0 to 5.5V. It produces “true” RS-232-level voltages (both positive and negative) using built-in charge pumps and some small external capacitors. Just the ticket for what I needed.

    Alas, the MAX3232 isn’t really something one can run down to the local electronics shop

    Hobbyists like myself need to turn to the internet where such things are available in abundance for cheap from China, though one must be wary of counterfeits.

    Of course, I could order from legitimate Swiss distributors, but small-quantity pricing and shipping are extremely high (>$10 USD per chip!) compared to major US distributors like DigiKey and Mouser.

    In my case, I ended up buying a few boards like this one from an online vendor in China. The listing specifically states it had a MAX3232 chip.

    To the naked eye, everything seemed to be reasonable. The chip did have markings identifying it as a MAX3232 (falsely, as I later discovered; read on!).

    However, the first board failed after a few weeks, drew significant current, and dramatically overheated. By “overheated” I mean “blister-raising burn on my fingertip”-level-hot. Also, the data-transfer LEDs were glowing faintly all the time rather than flickering on and off when data was flowing.

    I swapped it out for another board

    Although it didn’t catch fire (thankfully!), it did fail after a few weeks and overheated just like the first one.

    Anyway, the markings are inconsistent and seem pretty low-quality. Definitely not something I’d expect from Maxim. For comparison, I had ordered a free MAX3232 sample directly from Maxim

    According to the date code, I ended up killing this chip in the name of science about 2-4 weeks after it was made. Sorry, little guy. Anyway, you can see the markings of the real chip are distinctly different from the fake chips. The differences are striking even with a handheld magnifying glass

    Next, I decapsulated all three chips (two fake and one genuine) by dissolving them in hot nitric acid followed by an acetone wash and a few minutes in the ultrasonic cleaner. Don’t try this at home

    you can see the fake die is much smaller, has a much different appearance, and didn’t use gold bond wires.

    Both chips had the same markings: they appear to have been designed in November 2009, and the marking on the second line appears to be “WWW01”

    So far the replacements (either transplanted MAX3232s hand soldered onto the cheap Chinese boards after the fake chips blow up, or other reputable modules with genuine Exar SP3232s) have been going well


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