Fried microsd cards

[Jonathan Herbst]

I am looking into some fried microsd cards that I've seen from BeagleBone Blacks.  I'm not sure what is causing the problem yet, but while reviewing the BeagleBone Black schematic I noticed that the VDD_3V3B regulator looks like it might have swapped input and output capacitors.  According to the manual for the regulator, http://www.ti.com/lit/ds/symlink/tl5209.pdf, the minimum output capacitance should be 2.2uf, but the schematic shows a .1uf capacitor for the output capacitor, C20.  Just wondering if that was on purpose.  I don't think this is the cause of the fried sd cards I'm seeing because there's plenty of capacitance at the microsd port, but it looked odd to me.

[Gerald Coley]

There is plenty of capacitance on the output of that regulator found in other locations on the schematic..

That will not fry a 3.3V SD card.

Gerald 

On Fri, Oct 28, 2016 at 11:57 AM, Jonathan Herbst <amd...@gmail.com> wrote:

I am looking into some fried microsd cards that I've seen from BeagleBone Blacks.  I'm not sure what is causing the problem yet, but while reviewing the BeagleBone Black schematic I noticed that the VDD_3V3B regulator looks like it might have swapped input and output capacitors.  According to the manual for the regulator, http://www.ti.com/lit/ds/symlink/tl5209.pdf, the minimum output capacitance should be 2.2uf, but the schematic shows a .1uf capacitor for the output capacitor, C20.  Just wondering if that was on purpose.  I don't think this is the cause of the fried sd cards I'm seeing because there's plenty of capacitance at the microsd port, but it looked odd to me.

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