SD card

Secure Digital
(SD, SDHC, SDXC, SDUC)
From top to bottom: SD, miniSD, microSD
Media typeMemory card
Capacity
  • SD: Up to 2 GB
  • SDHC: over 2 GB to 32 GB
  • SDXC: over 32 GB to 2 TB
  • SDUC: over 2 TB to 128 TB
Block sizeVariable
Read mechanism
  • Standard: 12.5 MB/s
  • High-speed: 25 MB/s
  • UHS-I: 50 MB/s or 104 MB/s
  • UHS-II: 156 MB/s full-duplex, or 312 MB/s half-duplex
  • UHS-III: 312 MB/s full-duplex, or 624 MB/s half-duplex
  • Express: ≥ 985 MB/s full-duplex
Write mechanismVariable
StandardSD Standard
Developed bySD Association
Dimensions
  • Standard:
  • 32.0×24.0×2.1 mm (1.260×0.945×0.083 in)
    1,612.8 mm3 (0.09842 cu in)
  • Mini:
  • 21.5×20.0×1.4 mm (0.846×0.787×0.055 in)
    602 mm3 (0.0367 cu in)
  • Micro:
  • 15.0×11.0×1.0 mm (0.591×0.433×0.039 in)
    165 mm3 (0.0101 cu in)
Weight
  • Standard: ~2 g
  • Mini: ~800 mg
  • Micro: ~250 mg
UsagePortable devices, such as digital cameras and mobile phones (including most smartphones)
Extended fromMultiMediaCard
ReleasedAugust 1999

Secure Digital, officially abbreviated as SD, is a proprietary, non-volatile, flash memory card format the SD Association (SDA) developed for use in portable devices.

The standard was introduced in August 1999 by SanDisk, Panasonic (Matsushita) and Toshiba as an improvement on MultiMediaCards (MMCs).[1] SDs have become an industry standard. The three companies formed SD-3C, LLC, a company that licenses and enforces intellectual property (IP) rights associated with SD memory cards and SD host-and-ancillary products.[2]

In January 2000, the companies formed the SD Association (SDA), a non-profit organization to create and promote SD Card standards.[3] As of 2023, the SDA has approximately 1,000 member companies. It uses several SD-3C-owned trademarked logos to enforce compliance with its specifications and denote compatibility.[4]

  1. ^ "Matsushita Electric, SanDisk and Toshiba Agree to Join Forces to Develop and Promote Next Generation Secure Memory Card". DP Review. 1999-08-24. Retrieved 2016-02-23.
  2. ^ "Welcome to SD-3C, LLC". SD-3C. 2015-03-30. Retrieved 2016-02-23.
  3. ^ "Matsushita Electric, SanDisk and Toshiba to Form SD Association to Promote Next Generation SD Memory Card". Toshiba. 2015-03-30. Retrieved 2016-02-23.
  4. ^ "Using SD Memory Cards is Easy". SD Association. 2010-06-22. Archived from the original on 2021-10-29. Retrieved 2014-01-02.

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