Editing SD card (section)

==== UHS-I ====

Support for the Ultra High Speed interface was first specified in SD version 3.01, released in May 2010.<ref name="SDHCspec">{{cite web |publisher=SD Association |url=http://www.sdcard.org/downloads/pls/simplified_specs/archive/part1_301.pdf |title=SD Part 1, Physical Layer Simplified Specification, Version 3.01 |date=2010-05-18 |access-date=2013-11-25 |archive-url=https://web.archive.org/web/20131205014133/https://www.sdcard.org/downloads/pls/simplified_specs/archive/part1_301.pdf |archive-date=2013-12-05 |url-status=dead }}</ref> This version introduced support for a 100&nbsp;MHz clock frequency—four times the rate of the original "Default Speed"—which enabled transfer rates up to 50&nbsp;MB/s using four-bit Single Data Rate (SDR) transfers, designated as '''SDR50'''. An extended mode called '''SDR104''' (also part of UHS-I) further increased the clock frequency to 208&nbsp;MHz, enabling data rates up to 104&nbsp;MB/s.

Version 3.01 also introduced '''DDR50''', a [[double data rate]] mode that transmits data on both the rising and falling edges of the clock signal. At 50&nbsp;MHz, DDR50 can achieve 50&nbsp;MB/s transfer rates by sending four bits per edge, or eight bits (one byte) per full clock cycle. This mode is mandatory for microSDHC and microSDXC cards labeled as UHS-I.

A proprietary extension of UHS-I, known as '''DDR200''', was developed by SanDisk to further increase transfer speeds without requiring additional pins. It combines double data rate transfers with the 208&nbsp;MHz clock of SDR104 to reach speeds of up to 170&nbsp;MB/s.<ref>{{cite web |title=SanDisk Extreme microSDXC datasheet |url=https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/sandisk/product/memory-cards/extreme-uhs-i-microsd/data-sheet-extreme-uhs-i-microsd.pdf |website=Western Digital |access-date=2021-02-04 |archive-date=2021-01-08 |archive-url=https://web.archive.org/web/20210108210349/https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/sandisk/product/memory-cards/extreme-uhs-i-microsd/data-sheet-extreme-uhs-i-microsd.pdf |url-status=live }}</ref><ref>{{cite web |title=GL3232 |url=http://www.genesyslogic.com/en/product_view.php?show=83 |website=Genesys Logic |access-date=2021-02-04 |archive-date=2020-09-21 |archive-url=https://web.archive.org/web/20200921071215/http://www.genesyslogic.com/en/product_view.php?show=83 |url-status=live }}</ref> Although not part of the official SD specification, DDR200 has been adopted by several manufacturers, including Lexar (1066x series, up to 160&nbsp;MB/s), Kingston (Canvas Go Plus, up to 170&nbsp;MB/s), and MyMemory (PRO SD card, up to 180&nbsp;MB/s).