Bajdi:
lluchj:
Hello,My understanding is that the SMD voltage regulator within Arduino Mega ( NCP1117ST50T3G) drives up to 1A. The stepper motor I am connecting needs much lower current - why this may makes the voltage regulator fail?
In any case for sure next time I will use external voltage regulation circuitry to avoid this happening again.
Best regards,
Jaime.When you are powering the voltage regulator with 12V and drawing 1A from it, the voltage regulator has to dissipate 7W of heat (1A x 7V = 7W). The tiny voltage regulator only has the PCB to dissipate the heat, 7W of heat is a lot. There is no way that it can handle it and you will damage it. An Arduino can control a lot of things but not power them, certainly not motors. It is not made for that. I would never draw more then 200-300mA from the onboard regulator.
I agree with you on limiting use of the 5V pin to 200-300 ma. However the popular notion that one can damage the regulator from over current or over temperature, while a widely held view, goes against every linear voltage regulator datasheet I've ever come across. They all seem to have internal auto protection circuit that shuts down the output upon over temperature or over current draw. So saying that will damage the regulator goes against the manufactures designed protection. That is not to say that there is not ways to damage a linear regulator say by over voltage on the input or reverse current from output to input.
From a typical datasheet: ( Intelligent Power and Sensing Technologies | onsemi )
• Thermal Overload Protection
• Short Circuit Protection
• Output Transistor Safe Operating Area Protection
Lefty