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| SD (top), miniSD, microSD cards |
such as digital video camcorders, digital cameras, handheld computers, audio players and mobile phone.
The SD technology is used by more than 400 brands across dozens of product categories and more than 8,000 models.
SD comprises several families of cards:
the original, Standard-Capacity (SDSC) card,
SDSC (SD): 1 MB to 2 GB, some 4 GB available.
a High-Capacity (SDHC) card family,
SDHC: 4 GB to 32 GB
an eXtended-Capacity (SDXC) card family,
SDXC: >32 GB to 2 TB
and
the SDIO family with input/output functions rather than just data storage.
SD also comprises three different form factors: the original size, the "mini" size, and the "micro" size (see illustration). Electrically passive adaptors allow the use of a smaller card in a host device built to hold a larger card. There are many combinations of form factors and device families.
Host devices that comply with newer versions of the specification provide backward compatibility and accept older SD cards, but older host devices do not recognize newer cards. The SDA uses several trademarked logos to enforce compliance with its specifications and assure users of compatibility. This article explains several factors that can prevent the use of a newer SD card:
A newer card may offer greater capacity than the host device can handle.
A newer card may use a file system the host device cannot navigate.
Use of an SDIO card requires the host device be designed for the input/output functions the card provides.
The organization of the card was changed starting with the SDHC family.
Some vendors produced SDSC cards above 1 GB before the SDA had standardized a method of doing so.
