Current through Vin

[ricenbeanzzz]

Hey,

So I was planning to connect an external power supply to an Arduino to the Vin pin, Is 12 volts with a 500mA or 750ma fuse enough to have the board functioning properly. Also, how much current would left for the peripherals? By the way this is through a shield being implemented.

[UKHeliBob]

Welcome to the forum

Which Arduino board are you using and which peripherals does it have attached to which it provides power ?

[kolaha]

atmega328p allow pro pin source maximum 20mA, whole chip maximum 200mA.
the chip itself consumes 1.5mA.
UPD. Ah, yes, onboard 5V LDO regulator is able to provide ~100mA maximum.

[oldcurmudgeon]

Project power considerations

Using Vin is still a problem for many. I did some calculations and here are the results. The UNO uses the NCP1117ST50T3G regulator to generate 5V from Vin. Data sheet here. From the data sheet pages 2 and 8 it appears the maximum power dissipation is about 600mW. The difference between Vin and 5V will be dissipated as heat so dividing the max power by the difference voltage will give the maximum current. Vin......Difference .......Max current 12V............7V...................85ma 9V....…

[kmin]

@ricenbeanzzz

Is 12 volts with a 500mA or 750ma fuse enough to have the board functioning properly.

You don't need fuse to power arduino through vin pin. You can even use 100A power supply as long as voltage is between 7 and 12V. Lower is better. Everything above 7V is just waisted as heat in voltage regulator.

[camsysca]

@ricenbeanzzz We really do need to know exactly which product. Nano? Nano Every?

What?

[ricenbeanzzz]

Sorry its for the Arduino Mega.

[ricenbeanzzz]

Let me clarify, its for the arduino mega.

[jim-p]

How much current you can draw from the 5V pin with a 12V input has been highly debated on the forum.
For the total Vin current my vote is for about 120mA, that leaves about 60mA for everything else