microSD
microSD is a format for removable flash memory cards. SD is an acronym for Secure Digital. The cards are commonly used in cellular phones, as well as in handheld GPS devices, portable media players, digital audio players, expandable USB flash memory drives, Nintendo DS flashcarts, and digital cameras.
It is the smallest memory card available commercially; at 15 mm × 11 mm × 1 mm (about the size of a fingernail), it is about a quarter the size of an SD card.[1] There are adapters which allow a microSD card to be used in devices intended for SD, miniSD, Memory Stick Duo and even USB cards. However, they are not universally compatible. Many microSD cards sold online and in stores are packaged with an SD adapter to use the card in devices that take SD cards. TransFlash and microSD cards are the same (each can be used in devices made for the other), except that microSD adds support for SDIO mode, enabling non-memory cards like Bluetooth, GPS, and Near Field Communication devices.[2]
A point of confusion can come from the difference in the microSD and the newer microSDHC format. The SD and SDHC share a similar form factor, but not all devices are compatible with the newer high capacity format. This is even true with devices that have been developed by SanDisk such as their e200 series of MP3 players. Using 3rd party firmware however, SDHC reading capabilities can be possible.[3]
microSD cards are available in capacities from 64 MB to 16 GB. A 12 GB version was developed by SanDisk but never released.[4] In February 2009 Sandisk also announced a 32 GB version for the second half of 2009,[5] but as per end December 2009 it is not listed yet. Almost all cards with sizes over 2 GB are SDHC cards although some early 4GB SD Cards are not classified as SDHC.
History
The microSD format was originally created by SanDisk. It was originally called T-Flash, and then TransFlash, before being renamed microSD when adopted by the SD Card Association (SDA). Other flash card formats approved by the SDA include miniSD and SD card.
The SDA announced the microSD format at CTIA Wireless 2005 on March 14, 2005, and approval of the final microSD specification was announced on July 13, 2005. At launch, the microSD format was available in capacities of 32, 64, and 128 MB. SanDisk introduced a 2 GB microSD card in July of 2006, initially priced at 99 USD. Since then, prices for flash memory devices have fallen dramatically. The same 2 GB card as of April 2009 can be found for as little as 12 USD at department stores, and as of May 2009 for as little as 6 USD at online electronics stores.
Today 16GB versions are on the market for under 50 USD.
It is expected that the SDXC(upto 2TB data) format will eventually be carried over to the MicroSD cards, but a timeframe or announcement has not been made.
Comparisons
Template:MultiMediaCard comparison
Power Consumption
The power consumption of microSD cards varies by manufacturer, but appears to be in the range of 20-100 mA at a supply voltage of 3.3 V. Specifications from TwinMos technologies (http://www.twinmos.com.tw) list a maximum of 45 mA during transfer. Toshiba, on the other hand, lists 80-100 mA: http://www.toshiba-memory.com/en/micro_sd_cards.html.
See also
References
- ^ "microSD Card". SD Card Association. Retrieved 2008-09-13.
- ^ microSD definition (Phone Scoop)
- ^ Rockbox change 2007-08-22: Added support for MicroSDHC cards on Sansa e200
- ^ "SanDisk Hints at 16GB microSD Card, cancels 12GB model". PC Mag. 4 April 2008. Retrieved 2009-01-05.
- ^ "Sandisk Press Release". Sandisk Corporation. 2009-02-10. Retrieved 2009-12-29.
External links
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