why? What are the advantages of Micro USB over Mini USB that made USB-IF remove an existing standard and replace it with another standard that is essentially the same?
A major factor in abandoning mini-USB was that it was mechanically defective. Most people who have used a micro USB device that required many inputs will experience poor reliability after a large but not many uses.
The original mini-USB had a very poor input life – almost 1,000 entries in total claimed. This is about once a day for 3 years. Or 3 times a day for a year. Or… for some people, this order of reliability may be acceptable and problems may go unnoticed. For others it becomes a major issue. A photographer using a flash card reader may live out that life in as little as a year.
The original micro USB connector had slanted sides as it does today but was reasonably straight. (Much like the sides on the micro-A connector.) These are now so rare that I couldn’t find an image using a web search. This image is schematic only but shows the basic shape with slanted but straight sides.
USB Mini-A socket
Efforts were made to address low-life issues while maintaining backward compatibility and the current “zigzag sides” design was produced. Both plug and socket have been changed but sockets (“pot”) will still accept old straight-sided sockets. This is the look we are all so used to that the old one has been pretty much forgotten.
USB Mini-B socket USB Mini-B socket
Unfortunately, this change “only sort of worked”. The input life has been increased to about 5,000 cycles. This sounds high enough in theory but in practice the design was still wound up in terms of mechanical reliability. 5000 cycle is a very poor rating in the conductor industry. While most users will not achieve many input cycles, the actual reliability in heavy use is poor.
The micro-USB connector was designed with these past failures in mind and has an estimated life of approximately 10,000 input cycles. This is despite its apparent fragility and what may appear to be a less robust design. [This still seems pitifully low to me. Time will tell].
Closure In contrast to Micro USB, Micro USB has a passive closing mechanism that increases retention force but allows removal without active user action (apart from dragging). [It appears that closure may reduce the ‘working’ of the stopper in the vessel and may increase reliability.]
Micro and Micro USB connectors are of similar width. But the mini connector is much thinner (smaller vertical dimension). Some product designs have not been able to accommodate the height of the small bowl and will encourage a new thinner bowl and allow the use of thinner products. The micro USB socket was too tall for a slim design. For example – a number of Motorola “Razr” cell phones used micro-USB receptacles, which allowed designs to be thinner than would have been possible with a Mini-USB socket.
Specific Razr models that use MICRO-USB include the RAZR2 V8, RAZR2 V9, RAZR2 V9m, RAZR2 V9x, DROID RAZR, RAZR MAXX, and RAZR VE20.
Wikipedia on USB – see “Durability”.
micro USB connector manufacturer page
Micro-USB technology is developed by USB Implementers Forum, Inc. (USB-IF), an independent, nonprofit group that develops USB technology. Micro-USB connectors from Molex offer the advantages of a smaller size and greater durability compared to the Micro USB connector. Micro-USB connectors allow manufacturers to push the boundaries of thinner, lighter mobile devices with sleeker designs and greater portability.
Micro-USB replaces the majority of Mini-USB plugs and receptacles today. Micro-USB specifications support the current USB On-The-Go (OTG) accessory and provide complete mobile connectivity by enabling mobile 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 input cycles, and a passive locking mechanism that delivers higher extraction forces without sacrificing the ease of use of USB when syncing and charging mobile devices.
Once everything changes, everyone tends to. The new USB charging standard adopted by all mobile phone makers is one of the important factors of the popular USB connector. (or whoever wishes to stay). The standard relates primarily to the electrical standards required to allow mass charging and chargers, but a common mechanical interconnect system that uses various micro-USB components is part of the standard. Whereas in the past it was really important for a “whizzygig” device to be plugged into its supplied power supply, now it is essential that the power supply of any other device fits in with any other. A common plug and socket system is the minimum necessary for this to happen. While adapters can be used, this is an undesirable technique. As USB charging has become widely accepted not only for mobile phones but for xxxpods, xxxpads, pda and things in general, the common connector drive is accelerating.
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