# Arduino max power supply limit

What is the maximum current that can be supplied to an Arduino Mega board before frying/breaking?

Basically i have several components connected to my board which draw a total current of 1.6A (which i calculated through a table), and thinking of using a 9V 2A power supply. I know that the arduino voltage limit is 7-12V but just wondering about the current as I can't find it on the datasheets?

• I think you mean "supplied from"; you can supply infinite amps to it. If you components can use vin, then you're not really limited, other than to the pins/traces. Feb 18, 2019 at 20:17
• yes sorry i meant i will have an external 9V 2A power supply to power the arduino and my components. as i will be connecting this through the japan socket, the max current input limit would be 1A as suggested by @CrossRoads? Or is this also infinite? Thanks! Feb 18, 2019 at 21:39

1A coming in thru the barrel jack connecor, then you risk blowing the 1A rated reverse polarity protection diode. The 5V regulator will overheat at high currents above 7.5V. The chip itself can have 800mA put thru if if properly cooled and the IO limits of current per port are respected.

So 1.6A, no way.

• thanks for the info! so im assuming the max current that can be provided through the japan jack is 1A? Feb 18, 2019 at 21:09
• Thru the barrel jack, yes ,1A. Thru the USB jack, 0.5A. Feb 18, 2019 at 21:10

From the ATmega328P datasheet.

• One should specify that these are the limits of the MCU unit. But the current does not have to go through the MCU. For a 5V pin the limit comes from the power supply, 500 mA for USB and 1000 mA for the linear voltage regulator (barrel jack). In both cases one must subtract the power consumption of the board. Also note that USB power is disconnected as soon as you put voltage through the regulator: they have no chance to work concurrently. Dec 3, 2021 at 8:15

Your question isn't clear. Are you talking about drawing regulated 5V from the Arduino power supply? I believe the built-in regulator has a hard limit if 1A total output, but how much you can draw from it will depend on various factors (mostly how much waste heat it generates. If you drive it from 9V it will generate quite a bit of heat, since a linear regulator simply dissipates the excess voltage as heat. Better to use a 7V supply)

You won't be able to draw 1.6A of 5V from the Arduino. You should probably get a separate 2A 5V regulated power supply for your external components. Again though, your question isn't very clear so I'm not sure I'm answering what you're asking.

• Thanks for your reply. So the idea is to have an external power supply to power the arduino board along with its components. I re-did my calculations, and the total current and power dissipated by the components and arduino board would be 3.8W and 0.6A. Do you reckon this power supply would be enough amazon.co.uk/gp/product/B00HG9PT4K/… ? It's rated at 9V/650mA and says its for the arduino. The alternative solution would be to have a 9V/2A if this is pushing on the limit Feb 18, 2019 at 21:10
• Is that what your external components need? 9V? Most solid state components need regulated 5V. If your external components need 9V then you might get away with driving them from the 9V supply and also powering the Arduino into it's barrel connector using the same 9V supply. The Arduino regulator should handle fluctuations in input voltage as long as you don't draw so much current from the 9V supply that its voltage drops below 7V or so. Feb 18, 2019 at 21:15
• I have 2 8V stepper motors, a 3V LED light and HC05 bluetooth module Feb 18, 2019 at 21:25
• You should not cut it that close. A 2A supply would be a much better choice. You'd be better off using a separate low power 5V regulated supply for the Arduino. Keeping the power supplies separate will avoid big swings in voltage as your power components (motor and bluetooth module) turn on and off. Feb 19, 2019 at 1:55