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All manufacturer SD cards work in 3.3V based on SD specification.

In our recent design we have tested SD card connector power to 1.8V, I thought no SD card will boot but some of the SD card are boot some of them are not booting.

Could you please clarify me if there is any specification changes in recent microSD cards standards?

Marcus Müller
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ramesh6663
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2 Answers2

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In the newer SD 6.0 specification there is now a standard for cards to operate at 1V8 from start. The cards in question should carry the "LV" logo. Previously cards could start at 3v3 and then, via a command, switch to 1V8.

Here's the page to check: https://www.sdcard.org/developers/overview/low_voltage_signaling/index.html

Robin McBurnie
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SDHC and SDXC need to be able to switch to 1.8V IO operation after a certain command, so it's not that surprising that they might also work with 1.8V supply – after all, the switchability most likely implies the internal logic is simply run from a linear voltage regulator that drops the nominal 3.3V to a voltage that is at most 1.8V for all the logic.

Regarding standardization:

https://www.sdcard.org/downloads/pls/

doesn't say that a single 1.8V supply is permissible, so you're definitely driving things out-of-spec (Part 1, section 3.2 "supply voltage).

Marcus Müller
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  • Thanks for your feedback after i checked with the SD spec, Noticed it has different speeds and Class types. https://members.sdcard.org/downloads/pls/simplified_specs/part1_410.pdf Page 31. Regards, RK – ramesh6663 May 08 '17 at 07:19
  • No, it doesn't. I've commented on this before: p. 31 is about UHS-II cards (which are uncommon and have more contacts), which need **both** 1.8V and 3.3V, and, thus, my statement still stands: a **single** 1.8V supply voltage is illegal. – Marcus Müller May 08 '17 at 11:34