mini on 3.3v

Hi there,

Does anyone know if it is possible to run the arduino mini on 3.3V? If so how should i connect it.

Kind regards,

Erik

the datasheet for the Atmega 168 says "2.7 - 5.5V" power, but I am not sure what will happen to the regulator when you connect 3.3 to its output.

Worth a try though. Are you good at replacing SMT chips? Could be a good learning experience.

D

The mini doesnt have a regulator.

Give it 3.3v and it should run just fine.

The mini doesnt have a regulator.

Give it 3.3v and it should run just fine.

if you look at the schematics, it does have one: http://www.arduino.cc/en/uploads/Main/arduino_mini_schematic03.pdf but if i read it right, you can circumvent it by using the 5v in.

you might get little problems though if the atmega was configured for brownout detection. AFAIKT this is to shut it off automatically if the voltage drops below a certain point to save the flash memory.

if you have a mini it should be save to just try it. [EDIT: daniel pointed out that the regulator might not like the reverse voltage of 3.3v. you should keep that in the back of your head. still i think, it shouldn't burn anything as the mini works fine on the 5v from the USB adaptor ]

kuk

looking at the regulator datasheet, it seems like it should work. On the other hand they don't publish specs for driving current -into- the output pins of the reg, so you never know what might happen. If you don't need the regulator you could just remove it and run the chip on 3.5V.

D

Hi Guys,

Thank you very much for the replies. I also decided to test. It works!! This will make it easier to work mobile with other 3.3v devices.

Cheers Erik

if you look at the schematics, it does have one: http://www.arduino.cc/en/uploads/Main/arduino_mini_schematic03.pdf but if i read it right, you can circumvent it by using the 5v in.

Wow. I must have missed that. looks at picture again

Can you run a “regular” arduino with an ATMega168 at 3.3v? The only thing I could think of that would be a problem is the 16Mhz rate: the datasheet isn’t very clear on this point. It implies that 16mzh is within the range of the 3.3v supply.

Of course, I wouldn’t expect the USB chip to work, and I’m not sure that straight serial would either.

ckiick,

looking the datasheet (not summary, but this one: http://www.atmel.com/dyn/resources/prod_documents/doc2545.pdf)

on page 306 there is a graphic. It's not precise, but seems that 16MHz and 3.3v. is out of safe operating area. The curve is linear, so 3.3v. can be safe for up to 13.33MHz. 12MHz is ok.

Of course, I wouldn't expect the USB chip to work, and I'm not sure that straight serial would either.

As long as its inputs are 3.3v tolerant which they should be then it should work fine. :) It gets powered by the USB bus I think even when the Arduino isnt. Double check the schematic.

There is nothing wrong with overclocking a AVR either. ;)