SDUC Cards compatibility with SDXC Host

Memory Cards Compatibility
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1

Hi Team,

We have a design where an SDXC host is interfacing with a 2TB SDXC Card. I hear Sandisk will come out with a SDUC 4TB SD Card soon. Would such a 4TB Card be backwards compatible with the SDXC host, at SDXC operating speeds?

Looking forward to your response!

2

I have read the standard and it should be fine. The only wrinkle is the SD express cards which will need a new card reader.

I have tried a lot of cards on my low cost USB reader and all work.

3

Hi @leaning1234,

SDUC (Secure Digital Ultra Capacity) cards like the upcoming 4TB models are not backward compatible with SDXC-only hosts, as they follow a different specification and file system (exFAT remains, but addressing and capacity limits differ).

Your SDXC host may not recognize or support SDUC cards unless it explicitly supports the SD 7.0+ standard. For full compatibility and performance, using a host/device designed for SDUC is recommended.

4

AFAIK SDUC cards are SD Express based and need a new card reader. The old SDXC is based on the same older card slot.