# Max current of Vin and 5V pin on Arduino Nano

What is the max current of the Arduino Nano's Vin (30) and 5V (27) pins?

It's hard to say. The maximum the on-board regulator can provide is 800mA. However the actual amount it can provide at any time depends on other external factors - most notably:

• The voltage of your supply
• The ambient temperature around the board
• The thermal mass of the copper the tab is soldered to

The higher your input voltage the more excess voltage has to be converted to heat. When it gets too hot it overheats and (theoretically) shuts down.

Also the board itself will take some of the maximum 800mA quota, say 50mA (guestimate), so that leaves 750mA theoretical maximum for the 5V pin - but only when powered from not much more than 6.2V (5V + 1.2V regulator dropout voltage).

However, if you are powering from the USB port then it is limited to whatever the USB port can provide (100mA for a passive hub, 500mA for a normal USB port, 2A for a CDP).

The VIN current will be the same as the 5V pin current + the board current.

• Oops. Silly me, should have read better. – Gerben Feb 26 '17 at 13:33
• @gerben It happens... – Majenko Feb 26 '17 at 13:34

What is the max current of the Arduino Nano's Vin (30) and 5V (27) pins?

it depends on the power dissipation limits (and to a less extent the current limit) on the regulator. the power dissipation is determined by the load your arduino and its loads draw, and the voltage dropout on the regulator.

the other part of the thermal limit is the thermal resistance of the package and ambient temperature.

Most of them use el cheapo 1117 regulators in sot223 that has a limit of 1amp + a thermal limit of 100c/w. so max power dissipation should be less than 1w. That means a practical limit of 0.5amp under the most aggressive conditions (2v dropout, or 7v input).

at 9v input, max of 0.25amp. at 12v input, a max of 0.15amp. ...