The SD card is a proprietary, non-unstable, flash enhance memory retention card format developed by the SD Affiliation (SDA). They are available three bodily types: the full-size SD, the smaller miniSD (now obsolete), Memory Wave and the smallest, microSD. Owing to their compact type factor, SD playing cards have been extensively adopted in quite a lot of portable client electronics, together with digital cameras, camcorders, video sport consoles, cellphones, action cameras, and digicam drones. The format was launched in August 1999 as Safe Digital by SanDisk, Panasonic (then known as Matsushita), and Kioxia (then part of Toshiba). It was designed as a successor to the MultiMediaCard (MMC) format, introducing a number of enhancements including a digital rights management (DRM) characteristic, a extra durable bodily casing, enhance memory retention and a mechanical write-protect change. These improvements, mixed with strong business support, contributed to its widespread adoption. To handle licensing and intellectual property rights, the founding companies established SD-3C, LLC. In January 2000, in addition they formed the SD Affiliation, a non-revenue organization liable for growing the SD specs and promoting the format.

As of 2023, the SDA contains roughly 1,000 member companies. The association makes use of trademarked logos owned by SD-3C to implement compliance with official requirements and to point product compatibility. In 1994, SanDisk launched the CompactFlash (CF) format, one in every of the primary profitable flash memory card sorts. CF outpaced a number of competing early codecs, together with the Miniature Card and SmartMedia. However, the late nineties saw a proliferation of proprietary codecs such as Sony's Memory Stick and the xD-Image Card from Olympus and Fujifilm, leading to a fragmented memory card market. To handle these challenges, SanDisk partnered with Siemens and Nokia in 1996 to develop a new postage stamp-sized memory card referred to as the MultiMediaCard (MMC). While technically modern, MMC adoption was slow, and even Nokia was slow to combine support for it into its mobile units. In 1999, SanDisk was approached by Panasonic (then generally known as Matsushita) and Kioxia (then part of Toshiba) to develop a new format as a second-technology successor to MMC.

The objective was to create a portable, high-efficiency memory card with built-in safety options and broader interoperability. Involved about shedding market share to Sony's proprietary Memory Stick, Toshiba and Panasonic saw the collaboration as a possibility to determine an open, industry-backed standard. Panasonic and Toshiba, who had beforehand collaborated on the Tremendous Density Disc (a DVD precursor), reused its stylized "SD" brand for the Safe Digital (SD) card format. Anticipating the growth of MP3 gamers, additionally they advocated for digital rights administration (DRM) help seeking to reassure content material publishers cautious of piracy. The DRM system adopted-Content material Protection 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. Though typically cited as an element in the format's broad industry help, Memory Wave CPRM was rarely applied in practice. SD playing cards additionally featured a mechanical write-protect switch, and early SD slots maintained backward compatibility with MMC cards. Based on SanDisk, consumer adoption was accelerated by Toshiba and Panasonic's dedication to launching compatible units in parallel with the cards.

To assist standardization and interoperability, SanDisk, Toshiba, and Panasonic introduced the creation of the SD Affiliation (SDA) at the January 2000 Client Electronics Show (CES). Headquartered in San Ramon, California, the SDA initially included 30 member firms and has since grown to encompass around 800 organizations worldwide. At the March 2003 CeBIT commerce show, SanDisk introduced and demonstrated the miniSD card format. The SD Affiliation (SDA) adopted miniSD later that year as a small-type-issue extension to the SD card customary, intended primarily to be used in mobile phones. Nevertheless, the format was largely phased out by 2008 following the introduction of the even smaller microSD card. TransFlash name stays in common use as a generic time period for microSD playing cards. A passive adapter allows microSD playing cards to be utilized in standard SD card slots, sustaining backward compatibility throughout gadgets. The storage capability of SD cards elevated steadily throughout the 2010s, driven by advances in NAND flash manufacturing and interface speeds. In January 2009, the SDA launched the Safe Digital extended Capability (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 providing capacities of 32 to 64 GB and skim/write speeds of several hundred megabits per second. Shopper adoption accelerated as digital cameras, smartphones, and card readers gained SDXC compatibility. By 2011, manufacturers supplied SDXC cards in sixty four and 128 GB capacities, with some models supporting UHS Velocity Class 10 and faster. The Safe Digital Ultra Capacity (SDUC) specification, announced in 2018, expanded most capacity to 128 TB and elevated theoretical transfer speeds to 985 MB/s. There are four outlined SD capacity requirements: Standard Capability (SDSC), High Capability (SDHC), Extended Capacity (SDXC), and Ultra Capacity (SDUC). Along with specifying most storage limits, these requirements also define preferred file systems for formatting cards. The unique Safe Digital (SD) card was introduced in 1999 as a successor to the MMC format. The identify SD Standard Capability (SDSC) was applied later to differentiate it from newer variants.