What is the maximum power draw in mA that one can safely do from the 3.3v pin?
Are the limits the same between the Giga and the Uno R4 minima? If they are different what are they for each board?
If only by chance. There is no reason that the limits of boards from different families should be the same.
I suggest to read here
- Search and open the board page
- Open "Tech Specs"
- Search for "Power"
Does the 8mA really apply to the 3.3v power rail pin?
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Check the schematic of the specific Arduino board you have. Look for the part number of the 3.3V regulator and then its specs. You will find your answer there.
For example, the Arduino Uno R3 includes an LP2985-33DVBR by Texas Instruments.
This regulator can support an output of 150mA continuously. It is not advisable to operate any device at its limit, although TI says it includes internal current limiting and thermal protection.
Hmm, the Giga uses MP2322 which according to its data sheet supports up to 1A of output on 3.3v side. I think that I would be pulling maximum of 250mA from the 3.3 power rail off the Giga. Any issues with that?
Not with that. Just make sure that you do no exceed the total current available for your power supply.
Are you powering your Arduino via USB? Most PC USB ports support up to 500mA
It’s being powered via 24v 3A power supply on the VIN side.
Consider also that the board is designed to use 3.3V all around, supplied by the MP2322, so its spare current capability will be less than the rated 1A.
Very true, I do use the Giga display shield and as far as I can see it also is powered via the 3.3v. Have not been able to find any data as far as amount of current that it can pull.
@Jorgetrujilloroman do you know if I would be able to pull up to 150 mA from the 3.3 v pin when using the Giga with the Giga display? Power would be supplied by sending 24v @ 3A to VIN.
Please note that the 1A max current according to the power tree is not fully available as the output powers other components:
I understand that. What I don't understand is the amount of current that is available on 3.3 power rail. Do you have any safe range of current that can be pulled from the 3.3 power rail? Please note that I am using the Giga Display. Any feedback is much appreciated.