The SD card is a proprietary, non-volatile, flash memory card format developed by the SD Association (SDA). They come in three bodily forms: the complete-measurement SD, the smaller miniSD (now out of date), and the smallest, microSD. Owing to their compact type issue, SD cards have been extensively adopted in a wide range of portable consumer electronics, including digital cameras, camcorders, video sport consoles, cell phones, motion cameras, and digital camera drones. The format was launched in August 1999 as Secure Digital by SanDisk, Panasonic (then often called Matsushita), and Kioxia (then a part of Toshiba). It was designed as a successor to the MultiMediaCard (MMC) format, introducing several enhancements including a digital rights management (DRM) function, a extra durable bodily casing, and a mechanical write-protect change. These enhancements, combined with sturdy industry support, contributed to its widespread adoption. To handle licensing and mental property rights, the founding corporations established SD-3C, LLC. In January 2000, in addition they formed the SD Association, a non-revenue group liable for developing the SD specifications and promoting the format.

As of 2023, the SDA consists of approximately 1,000 member companies. The association makes use of trademarked logos owned by SD-3C to implement compliance with official requirements and to indicate product compatibility. In 1994, SanDisk introduced the CompactFlash (CF) format, one among the primary successful flash memory card sorts. CF outpaced a number of competing early formats, including the Miniature Card and SmartMedia. However, the late nineties saw a proliferation of proprietary codecs resembling Sony's Memory Wave Stick and the xD-Image Card from Olympus and Fujifilm, resulting in a fragmented Memory Wave clarity support card market. To handle these challenges, SanDisk partnered with Siemens and Nokia in 1996 to develop a new postage stamp-sized memory card known as the MultiMediaCard (MMC). While technically progressive, MMC adoption was gradual, and even Nokia was gradual to combine support for it into its cell gadgets. In 1999, SanDisk was approached by Panasonic (then often called Matsushita) and Kioxia (then a part of Toshiba) to develop a brand new format as a second-technology successor to MMC.

The goal was to create a portable, high-efficiency memory card with built-in security features and broader interoperability. Involved about shedding market share to Sony's proprietary Memory Stick, Toshiba and Panasonic saw the collaboration as a chance to establish an open, industry-backed customary. Panasonic and Toshiba, who had beforehand collaborated on the Super Density Disc (a DVD precursor), reused its stylized "SD" logo for the Secure Digital (SD) card format. Anticipating the growth of MP3 players, additionally they advocated for digital rights management (DRM) support in search of to reassure content publishers cautious of piracy. The DRM system adopted-Content Safety for Recordable Media (CPRM)-had been developed earlier in partnership with IBM and Intel, and Intel and complied with the Secure Digital Music Initiative standard. Although usually cited as an element in the format's broad business assist, CPRM was hardly ever implemented in apply. SD playing cards also featured a mechanical write-protect switch, and early SD slots maintained backward compatibility with MMC playing cards. In line with SanDisk, client adoption was accelerated by Toshiba and Panasonic's commitment to launching suitable devices in parallel with the cards.

To assist standardization and interoperability, SanDisk, Toshiba, and Panasonic announced the creation of the SD Affiliation (SDA) at the January 2000 Client Electronics Present (CES). Headquartered in San Ramon, California, the SDA initially included 30 member corporations and has since grown to encompass round 800 organizations worldwide. On the March 2003 CeBIT commerce show, SanDisk launched and demonstrated the miniSD card format. The SD Affiliation (SDA) adopted miniSD later that year as a small-type-factor extension to the SD card commonplace, supposed primarily for Memory Wave use in cell phones. However, the format was largely phased out by 2008 following the introduction of the even smaller microSD card. TransFlash title stays in widespread use as a generic term for microSD cards. A passive adapter permits microSD cards to be utilized in normal SD card slots, sustaining backward compatibility across units. The storage capability of SD cards elevated steadily all through the 2010s, driven by advances in NAND flash manufacturing and interface speeds. In January 2009, the SDA introduced the Safe Digital extended Capacity (SDXC) format, supporting up to 2 TB of storage and switch speeds as much as 300 MB/s.

SDXC playing cards are formatted with the exFAT file system by default. The primary SDXC cards appeared in 2010, with early fashions offering capacities of 32 to sixty four GB and browse/write speeds of a number of hundred megabits per second. Consumer adoption accelerated as digital cameras, smartphones, and card readers gained SDXC compatibility. By 2011, manufacturers provided SDXC playing cards in 64 and 128 GB capacities, with some models supporting UHS Velocity Class 10 and sooner. The Safe Digital Extremely Capability (SDUC) specification, introduced in 2018, expanded most capability to 128 TB and increased theoretical switch speeds to 985 MB/s. There are 4 outlined SD capability standards: Standard Capacity (SDSC), Excessive Capacity (SDHC), Prolonged Capability (SDXC), and Extremely Capability (SDUC). Along with specifying maximum storage limits, these requirements additionally outline most well-liked file programs for formatting cards. The unique Safe Digital (SD) card was introduced in 1999 as a successor to the MMC format. The identify SD Normal Capability (SDSC) was applied later to tell apart it from newer variants.