Why was Mini USB deprecated in favor of Micro USB?
Mini USB connectors were standardized as part of USB 2.0 in 2000. In 2007, the USB Implemeters Forum standardized Micro USB connectors, deprecating Mini USB connectors four months later.
Why? What are the advantages of Micro USB over Mini USB that made USB-IF rip out an existing standard and replace it with another one that's basically the same thing?
Quote by Russell McMahon: *"A major factor in abandoning mini-USB is that it was fatally flawed mechanically."* Sorry Russell, but I am missing the evidence for that as well as everyday life contradicts that either. A micro-usb is much more prone too because you don't need much efforts to push it in **upside down** - almost impossible on a mini-usb. just google how many users made that experience either themselves or their kids including myself on a BB Playbook and Archos IT. In my opinion it's a lousy construction, not to speak crap!
The world went down hill after parallel ports stopped being the norm. Bring back DB25 I say. (seriously)
A major flaw:
A major factor in abandoning mini-USB is that it was fatally flawed mechanically. Most people who have used a mini-USB device which requires many insertions will have experienced poor reliability after a significant but not vast number of uses.
The original mini-USB had an extremely poor insertion lifetime - about 1000 insertions total claimed. That's about once a day for 3 years. Or 3 times a day for one year. Or ... For some people that order of reliability may be acceptable and the problems may go unnoticed. For others it becomes a major issue. A photographer using a flash card reader may expend that lifetime in well under a year.
The original mini-USB connector had sides which sloped as at present but they were reasonably straight. (Much the same as the sides on a micro-A connector). These are now so rare that I couldn't find an image using a web search. This image is diagrammatic only but shows the basic shape with sloped but straight sides.
Efforts were made to address the low lifetime issues while maintaining backwards compatibility and the current "kinked sides" design was produced. Both plug and socket were changed but the sockets ("receptacle") will still accept the old straight sided plugs. This is the shape that we are all so used to that the old shape is largely forgotten.
Unfortunately, this alteration "only sort of worked". Insertion lifetime was increased to about 5,000 cycles. This sounds high enough in theory but in practice the design was still walking wounded with respect to mechanical reliability. 5,000 cycles is a very poor rating in the connector industry. While most users will not achieve that many insertion cycles, the actual reliability in heavy use is poor.
The micro-USB connector was designed with these past failings in mind and has a rated lifetime of about 10,000 insertion cycles. This despite its apparent frailty and what may appear to be a less robust design. [This still seems woefully low to me. Time will tell].
Latching Unlike mini USB, Micro USB has a passive latching mechanism which increases retention force but which allows removal without active user action (apart from pulling). [Latching seems liable to reduce the plug "working" in the receptacle and may increase reliability].
The micro and mini USB connectors are of similar width. But the micro connector is much thinner (smaller vertical dimension). Some product designs were not able to accommodate the height of the mini receptacle and the new thinner receptacle will encourage and allow thinner products. A mini-USB socket would have been too tall for thin design. By way of example - a number of Motorola's "Razr" cellphones used micro-USB receptacles, thus allowing the designs to be thinner than would have been possible with a Mini-USB receptacle.
- Specific Razr models which use MICRO-USB include RAZR2 V8, RAZR2 V9, RAZR2 V9m, RAZR2 V9x, DROID RAZR, RAZR MAXX & RAZR VE20.
Wikipedia on USB - see "durability".
Connector manufacturer Molex's micro USB page
Micro-USB technology was developed by the USB Implementers Forum, Inc. (USB-IF), an independent nonprofit group that advances USB technology. Molex's Micro-USB connectors offer advantages of smaller size and increased durability compared with the Mini-USB. Micro-USB connectors allow manufacturers to push the limits of thinner and lighter mobile devices with sleeker designs and greater portability.
Micro-USB replaces a majority of Mini-USB plugs and receptacles currently in use. The specification of the Micro-USB supports the current USB On-The-Go (OTG) supplement and provides total mobile interconnectivity by enabling portable devices to communicate directly with each other without the need for a host computer.
... Other key features of the product include high durability of over 10,000 insertion cycles, and a passive latching mechanism that provides higher extraction forces without sacrificing the USB's ease-of-use when synchronizing and charging portable devices.
Once all can change, all tend to. A significant driver to a common USB connector is the new USB charging standard which is being adopted by all cellphone makers. (Or all who wish to survive). The standard relates primarily to the electrical standards required to allow universal charging and chargers but a common mechanical connection system using the various micro-USB components is part of the standard. Whereas in the past it only really mattered that your 'whizzygig' could plug into its supplied power supply, it is now required that any whizzygig's power supply will fit any other device. A common plug and socket system is a necessary minimum for this to happen. While adapters can be used this is an undesirable approach. As USB charging becomes widely accepted not only for cellphones but for xxxpods, xxxpads, pda's and stuff in general, the drive for a common connector accelerates. The exception may be manufacturers whose names begin with A who consider themselves large enough and safe enough to actively pursue interconnect incompatibility in their products.
Once a new standard is widely adopted and attains 'critical mass" the economics of scale tend to drive the market very rapidly to the new standard. It becomes increasingly less cost effective to manufacture and stock and handle parts which have a diminishing market share and which are incompatible with new facilities.
I may add some more references to this if it appears there is interest - or ask Mr Gargoyle.
Large list of cellphones that use micro-USB receptacle
A few more images allowing comparisons of a range of aspects including thickness, area of panel, overall volume (all being important independently of the others to some for various reasons) and retention means.
Large Google image samples each linked to a web page
Useful discussion & brief history Note: they say (and, as Bailey S also notes)
- Why Micro types offer better durability?
Accomplished by moving leaf-spring from the PCB receptacle to plug, the most-stressed part is now on the cable side of the connection. Inexpensive cable bears most wear instead of the µUSB device.
Russell, I don't think the micro USB connector was in wide use by the time the Motorola RAZR was out. The RAZR's had mini USB connectors.
@W5VO - We're both right :-). My point was that the Razr was an early adopter. The early Razrs used mini USB. They changed to micro USB in 2007 (slimmer too I think). Here's a Razr VE20 Micro USB data cable image and another and some Razr micro USB chargers. This page has a large list of phones that use a micro USB receptacle.
@Russel - I still use a Razr V3M from early 2007 on a daily basis. It has a mini USB connector, and it still works fine. I charge it about every other day. How's that for a data point? :)
@Kevin Vermeer - All data points welcome. I'll add it to the ones from the numerous dead or flaky card readers that I have had. Presumably Motorola would have taken more care with he connector quality than most Asian card reader manufacturers. I have had ongoing reliability problems with many mini-USB connectors - to the extent that I tape USB cables in place on portable equipment and but card readers with captive cables.
I use to have a RAZR phone and then a ROCKR phone.. both had mini-USB(and this seemed to lead a trend where most cell phones started coming out with standard USB ports, be it micro or mini-USB). My parents got the RAZR2 when it first came out though and that had micro-USB
The description of shape seems off to me. The image you show is of a mini-A connector, and the micro-A has a rectangular shape while the sides on micro-B are angled. mini-A was extremely rare (only for OTG), and the connector you describe as newer seems to be mini-B. In my experience about 15% of micro-B connector latches fail nearly instantly, negating the claimed retention advantage (it is claimed the improvement is that the replaceable cable fails rather than the socket). And there's certainly no denying the micro connectors are mechanically weaker (largely due to thin metal).
@Passerby - your brute force edit in deleting reference to the Rzar phone was not helpful in view of the extensive discussion about this point in the comments. While a munber of Razr phones do not use uUSB, a number do, and it allows them to be thinner than they could be if mici-USB was used. Specific Razrs which us uUSB include: Specific Razr models which use MICRO-USB include RAZR2 V8, RAZR2 V9, RAZR2 V9m, RAZR2 V9x, DROID RAZR, RAZR MAXX & RAZR VE20. | I have reinserted a comment re Razr's and added the list of relevant models.
@RussellMcMahon And your patently false statement on the Original Razr having MicroUSB for size reasons was not helpful either, and after being corrected 2 & 1/2 years ago, you stubbornly didn't bother fixing it.
@Passerby - :-). You have usefully highlighted that the answer was able to be improved by editing. My intention was to cite some specific phones that attained thinness with uUSB that could not have been achieved with Mini-USB. At the time I wrote that I was not aware that some used Mini-USB BUT I provided a list of Razr's that did use uUSB and this was discussed in the notes. It's easy to see in hindsight and/or with adequate applied pedantry what can be improved in an answer - and I would probably have a new full time hobby if I went around all my answers* rererehoning them. *1500+ apparently
@passerby - If the wording needed improving to match the supplied list and the supplied notes then you would have been doing people a service by modifying the text. But just deleting the example and not replacing it with another or noting the N models of Razr for which it is true seems to me to fall below the minimum standard of "due care" / social contract / whatever. Mayhaps it doesn't seem that way to you. Either way, thanks for bringing it to my attention, and hopefully the new wording now properly conveys reality.
Here's a picture of the old mini USB from an old Atmel AVR32 dev board I had laying around: https://www.dropbox.com/s/adzpshtntga1grl/Photo%20May%2004%2C%2011%2025%2041.jpg?raw=1
With micro usb, the springs are in the cable, not the device connector... so the most weak part is the most replaceable.
@BaileyS Yes. Or, at least they say that helps :-). I added a few more ferences at the end and incorporated a comment to the effect of what you said from a page. Since writing this I've been surprisewd at how popular it was - I'd rather it wasn't but can;'t be helped. I've found in the 5 years since this was 1st posted that micro USB HAS been more reliable for me BUT that may in part be due to taking more care due to past failures.
@RussellMcMahon I always liked the micro connector better, but never had a problem at all with mini. We have worn out some micro USB cables, but not sure if that was laboratory style plugging or physical mistreatment.... Since they frequently carry almost 2 amps, physical failure is unnerving.
I feel like the key part of the answer is `the inexpensive cable bears most wear instead of the µUSB device`
@ArtB Quite possibly. In thge almost 8 years since I posted it this has become my top "scoring" answer. I'd rather it wasn't, but people seem to have a fascination with it. I do find that micro-USB cables die. And/but I just bought a used HP Windows 8 [!!!!] tablet where any uUSB cable needs to be angled downwards to allow charging - but works well when this is done.
@RussellMcMahon I feel the same way about my highest answer on SO. I have the same problem with my Kobo and someone leaned on the plugged. I feel like it pried up the socket and so now it needs downward pressure. I wish the standard called for the cable end to break before the socket damaged.
Every time this question comes up, someone inevitably brought up the plug cycles (5000 vs 10000). My experience proves otherwise. I have used USB Mini since released (Circa 2000 'til now) and have experienced only 1 bad USB connector, and that was due to me rolling my office chair over it.
I recently switched to USB Micro just because you can't get a phone with anything other than USB Micro, and within 3 months, the connectors on 3 out of 5 chargers have connectivity issues. The remaining 2 work under the "if bend it, then it works": http://www.youtube.com/watch?v=E0Dzp5l2PyY
None of the chargers fit snuggly into socket. The connectors are flimsy and get damaged easily. Just rolling up the charger and putting it in my pocket can cause the tip to break off.
So to summarize my data: - in 10 years, 1 USB Mini out of many have connectivity issue (due to being run over by a chair) - in 3 months, 3 out of 5 USB Micros fail and the remaining 2 are defective.
Of course, I am just one person, so N=1 may mean that I am a statistical anomaly. However, I would like to see the consortium's real world usage data.
The bottom line is nobody cares about # plugs 'til failure in laboratory situations. What the consumers care about is: how long will it last? It is quite possible that the USB Micro can withstand more plugs in laboratory environments, but in the real world, these chargers get rolled up, placed in pockets, thrown around, etc. I guess engineers sometimes forget this. Too hard, won't do it, so ignore it.
Briefly Googling for USB Micro failure vs USB Mini failure suggests that I may not be alone in this.
With respect to the "USB Micro is smaller" argument, they are the same width and only 1.2mm smaller in thickness. The average cell phone thickness is about 13-15mm. 1.2mm represents < 10% of the phone thickness, so I would argue 10% in thickness is a small price to pay for the durability improvement.
The nuisance in this is that I now have many USB Mini chargers sitting around that I have accumulated from devices in the past, and I am at a shortage for USB Micro chargers.
While cables and chargers cost close to nothing to make, they are > $10 to purchase. We know that in the industry, the profit margin for cables are very high.
Conspiracy theories aside. I would speculate that part of the move is economically motivated.
"People no longer buy chargers because they last too long. Let's come up with a new standard that don't, and come up with some BS to explain it."
I may agree with the first part, but I don't see any conspiracy; think that this standard is almost the first REAL standard, widely adopted by many designers and also supported by laws. And you can find cables at reasonable price, even though many branded cables are overpriced. The advantage is that you have much more choice.
Briefly googling shows that this seems to be a common nuisance for people world wide. http://amplicate.com/hate/microusb , http://forum.xda-developers.com/showthread.php?t=729552 , and the list goes on and on... Various social networking pages have started just for the purpose of "hating USB Micro". USB Mini did fine. Why switch?
I think that there will be ALWAYS people disliking new technologies or standards; it's a normal thing, and it will require some time before it will be accepted. But think to all the strange connectors that have been replaced: http://www.tekkeon.com/productcart/pc/catalog/ua-samnewordernumbered_411_detail.jpg People always complain about new things, until they get comfortable and until they will miss them when they will be changed.
There is always resistance to change, but to the degree we see here? Also, why replace a better product with something that is worse?
Analog cameras did fine, too. Sometimes for marketing reasons, sometimes for reliability, sometimes just because the new is better; things are replaced, that's it. You can stick to old products, but then you'll have problems because they will be rare. And I wouldn't necessarily say it's worse: I've had bad experiences with mini-USB, too.
That's a faulty analogy. Digital camera is a paradigm shift and potential for improvement is there, so the people who bought into it expect improvement in the future. Do you buy a USB Micro expecting improvement in the future? It's not a paradigm shifting idea. It's just a connector. Connectors are meant to be reliable aid to the actual product. When it's not reliable, its purpose is defeated.
The good thing about micro-USB is that UE has choosen it to replace all the proprietary types of connectors. That makes it good to me, and by now I didn't have any problems with it, so I can't speak against it. Nor I want to mindlessly defend it.
In the US, USB Mini was "the standard" for many years. People got used to USB Mini, and, as far as I know, there were no issues with stability, connectivity. Cameras, cell phones, GPS, etc. all shipped with USB Mini. All of a sudden, almost over night, everything shipped with USB Micro. All of a sudden, people's cables and chargers no longer work. On top of that, new cables and chargers they get for new devices are all flimsy and don't last nearly as long. What gives? I can't blame all the hate blogs and social networking pages.
I'm currently on the third micro USB charger for my phone because the plugs keep failling. Never had such an issue with any other connector (USB or otherwise) before.
The thing that really grinds my gears about micro USB is people using it where it is totally inappropriate. Such as on large dev boards. We have several $400+ dev boards that have had full surface mount micro USB ports ripped clean off, including the traces. There is more than enough space on these things for full size USB connectors, and these are expensive boards, why save 5 cents on the programming connector instead of installing something more robust???
I strongly agree with this answer and all comments. I have exactly one reliably working micro usb cable in my home, out of close to a dozen. My $150 mechanical keyboard's micro usb port is breaking and I am trying to resolder a mini USB port onto it. I never had issues with mini.
I was involved in discussions and part of the decision loop. Then a very big and leading mobile phone maker, Nokia, asked for it. They even designed most part with a leading connector maker. USB IF eventually bite the bullet and accepted. Probably 2B+ of these connectors are shipped to date.
It was Nokia who demanded it and the primary reason was size, they were desperately trying to save size and had plans around OTG.
Given that you were directly involved, I wish you provided a little bit more info about the reasons for micro-USB and against mini-USB (other than that some big OEM wanted it for unspecified reasons).
The extra-thin Micro-USB is far more suited to todays slimline portable devices (smart phones, etc). The Mini-USB just doesn't really fit right in the smart-phones etc of today.
As you rightly note, it does the exact same job as Mini-USB, even down to having an AB socket for USB-OTG Host/Device selection.
So they don't need the old Mini-USB any more. So it's deprecated. No point in having two, and the old one is too fat. So drop it in favour of the new one.
That's really all there is to it. It's thinner, and thus better.
it's funny; I have far more reliability problems with that ridiculous thin mini-usb. I love the old micro-usb "kinked edges" connector. Far more robust in my experience.
@endolith, I think a lot of people prefer mini over micro. I find the bulkier design easier to use, can't comment on reliability, I've never had either a mini or micro usb fail.
@rocker9455: Yeah, I guess my experiences are the same. I've had micro USB connectors fail, but not mini. I've had trouble figuring out the correct orientation of micro in the dark, but don't remember that being a problem with mini. I want to believe that micro is better because USB org says it's better, but I guess if it was shoved into the spec by a phone manufacturer, that might not be true.
@endolith, I've read that micro USB connectors allow either orientation because they have a second set of pins (in the opposite order) for the other side. This also means that if one pin fails, there is already another pin-to-pin connection in parallel with the failed connection.
While on the whole, I am satisfied with the switch to USB Micro, my only major gripe is the less obvious keying. Inserting the plug with good lighting is no problem (if you can see), but trying to plug in your cell phone after you've crawled into bed with the lights off can be a trial. As somebody who works with people with disabilities and medical conditions, I have heard from clients with compromised motor control, those with low vision, and those with distal neuropathies that they do experience a harder time plugging in their devices nowadays.
My hope is that the standard for both plug and receptacle can be altered slightly to yield a more obvious tactile marker so users can orient the connector and the device more easily. I imagine the USB-IF could do this while retaining backwards compatibility. I suspect it could be achieved simply by mandating a small raised dot or ridge on the plastic as well as a corresponding mark on the device near the connector. For clients with this complaint, I have taken to gouging their devices and chargers or using tactile paint. Did the same for myself.
@pilsetnieks, the tactile USB logo is always on the top side of the plug; however, the jack has no logo, and can be oriented any way on a device.
Or better would be to make the plug and socket completely symmetric so it doesn't matter which way you plug it in, which is what the upcoming Type-C connector is meant to address.
@pilsetnieks The USB logo on a blackberry cable is both tactile and on the bottom side. What you mentioned used to be natural for me, but ever since I got one of those, I'm in perpetual confusion. Standards only work when everybody follows them
My nearest sharp or hot tool makes tacktile cross hatch mark on the TOP of EVERY charger connector that passes my desk (even the wifes iPhone cables get the same treatment). It makes it much easier to insert in the dark.
To comment on the answer: Micro USB is *supposed* to have a connector convention where the USB cable's logo faces the user in normal device operation. This doesn't mean 'normal' has a single convention and at least smartphones have variation in the orientation of the Micro-B connector on the device.
Aside from being smaller, the Micro USB connector latches positively when connected, making it much less prone to failure when the cable is wiggled in the port. In other words, unlike the Mini USB connector which could slip out if wiggled in the port, Micro USB holds the connector captive in the port with two latches at the male end, so that even if the port and cable connection is loose, electrical connectivity can be reliably maintained.