Flash-based detachable media, equivalent to SD playing cards, have a number of use-cases in merchandise starting from content material seize gadgets to transportable sport consoles. Many computing methods (together with PCs and smartphones) additionally make use of them to reinforce the accessible storage capability. There are two predominant requirements our bodies on this section – the SD Association (SDA) and the CompactFlash Association (CFA), with the SDA is liable for the Secure Digital playing cards (SD / microSD), and the CFA has the CompactFlash and CFast card markets.
The merchandise at present servicing this market section are based mostly on know-how requirements drafted when SATA was the top of inside storage efficiency, however in reality each requirements our bodies jumped on to the NVMe bandwagon within the late 2010s. Removable reminiscence playing cards based mostly on PCIe / NVMe are slowly beginning to seem available in the market – CFexpress from CFA, and SD Express from the SDA. Both ADATA and Lexar have introduced plans to launch their SD Express playing cards throughout the subsequent few quarters. The playing cards from each distributors are based mostly on the Silicon Motion SM2708 controller.
Silicon Motion sampled us its SM2708 reference design (with a 250GB capability) to place by way of our rigorous reminiscence playing cards analysis suite. This overview takes an in depth have a look at the efficiency of the cardboard along side Realtek’s RTL9211DS card reader reference design. It additionally serves as a preview of what customers can anticipate from SD Express playing cards showing available in the market over the following few quarters.
Lets Go: The Rise of PCIe and NVMe
SD playing cards and CompactFlash playing cards have emerged because the storage media of selection for content material seize gadgets equivalent to digital cameras and camcorders. SD playing cards have additionally loved help within the transportable sport console area and as boot drives for single-board computer systems. Currently well-liked SD and CF playing cards are based mostly on requirements developed when SATA dominated the roost because the switch protocol of selection for inside storage gadgets.
As PCIe-based NVMe took the SSD storage market by storm, each the SDA and CFA launched detachable card requirements based mostly on PCIe. The CFA had truly jumped on to PCIe fairly early, with a 1Gbps normal in 2011 – the XQD card format. However, lack of backwards compatibility with current CompactFlash readers meant that the format by no means actually took off regardless of making its method into retail. While the unique CF playing cards have been based mostly on PATA (the precursor to SATA), a quicker model based mostly on SATA was launched in 2009 as CFast. In 2016, the CFA introduced plans for the CFexpress normal and it was printed in mid-2017. CFexpress playing cards retain the XQD form-factor, and some CFexpress playing cards are already available in the market.
SD playing cards are additionally well-liked in a number of market segments. In order to serve the wants of all serviced markets, the SD Association launched the NVMe-based SD Express normal (SD 7.0) in 2018, with a SD 8.Zero follow-up in 2020. SD playing cards in addition to card readers based mostly on these new requirements have been making the rounds at varied commerce exhibits since 2019. However, none went on to seem within the retail market. That is about to vary within the coming months, with each ADATA and Lexar asserting plans to launch their SD Express playing cards based mostly on the Silicon Motion SM2708 card controller throughout the subsequent few quarters.
What We’re Testing Today: SD 7.1 Reference Designs
Consumers want each SD Express playing cards and card readers as a way to make the most of all the advantages of PCIe / NVMe within the SD form-factor. While SD Express playing cards are being enabled by controllers such because the SM2708, card readers platforms based mostly on JMicron and Realtek have additionally appeared in varied trade-shows (such because the RTS5261 demonstrated at Computex 2019). Silicon Motion coordinated with Realtek to pattern their 250GB SM2708 reference design together with a card…
