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I have an hobbyist/newcomer pcb project that needs a SD card connector. I link the datasheet of the part: DM3AT SD connector spec.

At page 2, it says: Voltage rating : 125V AC

SD card spec says it can have a 3.3V(DC) input. My PCB is powered by a 5V current (micro usb) and a level shifter is present to convert to 3.3V where needed on the circuit.

--Question:

What should I do with that 125V AC? ignore it and put my 3.3 DC voltage to the VCC pin of the connector?

Everyone seems to do the same, even the modules have a level shifter but that is it.

I am a bit lost.

Thanks

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  • \$\begingroup\$ Voltage over 125V (AC) are liable to destroy the connector. Voltages over 3.3V (DC) are liable (almost certain actually) to destroy the card, plus the card requires 3.3V DC in order to actually work. Hopefully you care about both the connector and the card. It should be obvious how to comply with both of these requirements, which is to use 3.3V DC. (I'm not quite sure why the connector is specced for AC but it's not saying you are required to use AC here) \$\endgroup\$ – user253751 Mar 13 '18 at 22:13
  • \$\begingroup\$ The AC part put me in doubt (beginner here). But I get it now. I can go on :) \$\endgroup\$ – Kroma Mar 13 '18 at 22:18
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Tha is not a "SD card voltage rating"; that is a max rating for what is safe to apply to the connector. You don't ignore it – you happily realize you're not dealing with voltages anywhere close to that and don't have to worry about arcing within the connector.

(Just for clarity: an SD card does not tolerate 125 V AC. The connector would. Just as your bathtub withstands 98 °C hot water, but you in that certainly wouldn't.)

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