SDHC cards are physically and electrically identical to standard-capacity SD cards (SDSC). The SDHC trademark is licensed to ensure compatibility. The Secure Digital High Capacity (SDHC) format, announced in January 2006 and defined in version 2.0 of the SD specification, supports cards with capacities up to 32 GB. The SD card added Content Protection for Recordable Media (CPRM) security circuitry for digital rights management (DRM) content-protection.įull-size SD cards do not fit into the slimmer MMC slots, and other issues also affect the ability to use one format in a host device designed for the other.

While MMC uses a single pin for data transfers, the SD card added a four-wire bus mode for higher data rates.The SD specification envisioned capacities and transfer rates exceeding those of MMC, and both of these functionalities have grown over time.The card's electrical contacts are recessed beneath the surface of the card, protecting them from contact with a user's fingers.The SD specification defines a card called Thin SD with a thickness of 1.4 mm, but they occur only rarely, as the SDA went on to define even smaller form factors. Most SD cards are 2.1 mm (0.083 inches) thick, compared to 1.4 mm (0.055 inches) for MMCs.Asymmetrical shape of the sides of the SD card prevent inserting it upside down (while an MMC goes in most of the way but makes no contact if inverted).Secure Digital changed the MMC design in several ways: The second-generation Secure Digital (SDSC or Secure Digital Standard Capacity) card was developed to improve on the MultiMediaCard (MMC) standard, which continued to evolve, but in a different direction.

The SD card's small footprint is an ideal storage medium for smaller, thinner and more portable electronic devices. Electrically passive adapters allow a smaller card to fit and function in a device built for a larger card.

The three form factors are the original size, the mini size, and the micro size. The five families are the original Standard-Capacity (SDSC), the High-Capacity (SDHC), the eXtended-Capacity (SDXC), the Ultra-Capacity (SDUC) and the SDIO, which combines input/output functions with data storage. Secure Digital includes five card families available in three different sizes.

Sandisk secureaccess 3.01