Would this micro sd card module be reliable?

Other Hardware General Electronics
1

I'm working on a project that will play wav files from an sd card, but I've never used an sd card reader/writer before. I have read that some of the ones that use voltage dividers for the 3.3v on the interface i/o lines can be unreliable, dependant upon the card.

I found this micro sd card module on amazon, there are no reviews yet but it looks like it has a 3.3v regulator and another IC (not sure what it is), but it doesn't appear to use voltage dividers on the i/o lines.

So, do you think this would be a reliable reader/writer that would work with any micro sd card? Cost is a factor for me, that's why I am trying to find something cheap but reliable. TIA!

2

Looks to have active hardware for 5V/3.3V level conversion. I expect it would be fine.

3

Thanks for answering Crossroads, I had my fingers crossed that you would reply :slight_smile:

I'll definitely be getting that product to mess around with, sd cards have opened up a whole new ballgame for my tinkering, but I got to thinking - if I just powered a mega328 with 3.3v, I could just hook up a card slot directly to the chip (when I design a PCB for it), correct? Those little micro sd card slots are relatively inexpensive.

4

The most important thing for SD card reliability is the power supply.

3.3V is right on the limit of what's acceptable. If you can give it 3.5V it will make everything better. The spec is for 3.6V (although almost no SD cards require that much).

PS: The cards will actually tell you how many volts they need if you ask them.

5

fungus:
The most important thing for SD card reliability is the power supply.

3.3V is right on the limit of what's acceptable. If you can give it 3.5V it will make everything better. The spec is for 3.6V (although almost no SD cards require that much).

PS: The cards will actually tell you how many volts they need if you ask them.

Thanks! Is a cap on the card's pwr/gnd required/better for card performance and if so, what value(s)?

6

You can never have too many decoupling caps (ask Mike...)

I'd put at least a 0.1uF ceramic on there.

7

You sure about that, Fungus?

According to my abridged copy of the SD card specifications:

Voltage range:
High Voltage SD Memory Card – Operating voltage range: 2.7-3.6 V

So 3.3v is actually right in the sweet spot, while 3.6v is at the upper end of its tolerance. (Low voltage cards run at 1.8v.) Do you have info to the contrary, or is this practical experience talking?