Powering "Arduino Pro Mini 328 - 5V/16MHz" from higher voltages

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1

Hello,

I am interested in using the “Arduino Pro Mini 328 - 5V/16MHz” for a project of mine, where the main power supply rail is 18V. The product page for the Pro mini states that it can be powered from a maximum voltage 12V, and the schematics have a note saying 16V max for the “raw” input.

However, looking at the datasheet for the MIC5205 LDO, it has an absolute maximum of 20V as its input voltage. I would be willing to give 18V a try to power it. However, the only thing that stands between me and this experiment is the voltage rating of the input capacitor on that LDO. There is what seems to be a tantalum (?) 10 uF capacitor on the input side of that LDO, and I am trying to find out what the voltage rating is on that capacitor. This is C19 on the schematic. Any info would be appreciated!

Thanks!

2

Hello, and thanks for your question!

C19 is rated for 16 volts and it is indeed a tantalum cap. It’s going to do some not nice things if you feed it more than 16 volts.

You could use a [DC to DC converter to drop your 18 volt supply down to 5 volts and then connect that to VCC. That would prevent any issues with explode-y bits and also eliminates the heat the voltage regulator on the Pro Mini would be generating trying to regulate a higher voltage down to 5 volts.](DC/DC Converter - 5V 5W (R-78E) - COM-14453 - SparkFun Electronics)

3

Haha, the goal is indeed to avoid explode-y bits :slight_smile: Thank you for the reply. The application is a sensitive analog circuit, I am going to implement an external beefier LDO. Thanks!