SparkFun Forums

[mbogelund]

Hi,
What is the voltage range for powering the Redboard Artemis (Uno footprint) through VIN?
The Redboard Artemis Nano is documented to accept max 6 volts on VIN, the barrel jack on the Redboard Artemis takes 7-15 volts, and I can't find any documentation directly stating what voltage to apply to VIN on the Redboard Artemis.
So what is it?
Thanks in advance

Vkr Martin

[TS-Brandon]

The maximum input on the VIN pin is 6V. That's all the voltage regulator can handle.

[mbogelund]

OK, thanks!

[mbogelund]

Hi again,

I have a followup question:
I hooked up a 9V battery to my Redboard Artemis via the barrel jack power connector, and measured the voltage between GND and VIN.

It was 9 Volts.

How can it be that max voltage applied to VIN is limited to 6V, when a legitimate application of 9V via the barrel jack sets VIN to also 9V?

[n1ist]

Redboard Artemis Nano is limited to 6V on it's Vin pin. Redboard Artemis Uno and Redboard Artemis ATP specify Vin as 7-15V; for those two, a 9V battery is within the range.
Due to the series diode, Vin on the Uno and ATP versions of the Redboard Artemis will measure about a half volt lower than the voltage at the barrel jack.
/mike

[mbogelund]

Hi Mike,
Thanks for clearing that up.
Where is it specified that Vin is 7-15V on the Redboard Artemis Uno? I have searched for this, but found nothing on the Artemis Uno.
Also, are you sure about the "half volt lower" part? I measured 9.12V on Vin when connecting a 9V battery to the barrel jack, and I would be surprised if a regular 9V battery gives a voltage closer to 9.5V than to 9.0V.
Anyway, I'll check it later myself.
Vkr Martin

[n1ist]

I based it on the picture (top silkscreen right behind the barrel jack) and schematic at https://cdn.sparkfun.com/assets/4/5/a/3 ... ematic.pdf. As for the diode drop, it is dependent on the current being drawn; that's the reason for the "about". At low current draw, the drop will be negligible; as the current gets higher, the drop will get closer to the half-volt amount for a Schottky diode.
/mike

[liquid.soulder]

The voltage regulator is only rated for up to 6V on its input. It is a low drop out regulator so depending on how much current you draw you may be able to successfully use 3.3V directly on the VIN pin. But I would not suggest going above 6V on the VIN pin

[n1ist]

That depends on which board you are using - Uno and ATP use the LM1117, which is rated to 15V absolute max input. Nano has a different regulator with a 6V max input. At least according to the documentation on the Sparkfun site.
/mike

[mbogelund]

Thanks again, Mike, you've been very helpful. And yes, you are absolutely right, my question was specifically on the Redboard Artemis Uno, since it's easy to find the 6V max on the Nano version specified on its product page.