SDIO interface voltage levels

I want to provide a SD card interface to WP7607, and I’m looking at the mangoh red board schematic as a baseline. But I can’t really work out the voltage levels…

It’s my understanding that SD cards operate at either 1.7-1.95v or 2.7-3.6v

I can’t really see the relevance of the 2.85v in the WP Tech Spec? It seems very precise but doesn’t seem to relate to anything. On top of that the Mangoh board uses a SD supply of 2.95v which again is precise but I can’t see the reason why.

Could somebody please enlighten me?


do you mean you want to turn down the output of module SDIO pin to be 1.8V?

Hi. No I wanted to know the significance of the 2.85v value, and why the Mangoh board is using 2.95v (as opposed to 3.0 or 3.3v)

sorry, no idea, but i found that it still works for 3V SD card system.