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Basic Electronics » Can I Power the ATmega168 with 3.3 V?

September 17, 2012
by karam
karam's Avatar

I looked through the datasheet for the ATmega168 and it appears to me that I could power it off 3.3 V. However, I wanted to double-check here just to see if anyone knows if that can be done, and if that is okay for the microcontroller... Any ideas? Also should I switch the oscillator to drive it with a lower frequency? Thanks in advance!

September 19, 2012
by Ralphxyz
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Hi karam, I believe you can still use the Nerdkits's crystal at 3.3 V I believe you have to slow the mcu down at 2.8 v.

ralph

September 20, 2012
by karam
karam's Avatar

Thanks, Ralphxyz.

I made a graph from Table 29-2 in the datasheet and found the relation between input voltage and max frequency to be linear:

http://i.imgur.com/uJtAp.png

It looks to me like 3.3 won't quite cut it without reducing the clock speed, but 3.6 should work. And, that solves the problem for me as this is going to be part of a circuit with a GPS receiver that needs 3 to 3.6 V :)

September 20, 2012
by karam
karam's Avatar

Now I just have to figure out how to step up my 2.4 - 3 V power supply (two AAAs in series) to 3.6 V... I've found plenty of DC-DC converters on Digi-Key that work for those voltages, but I'm only estimating about 50 - 200 mA current which seems to be below the minimum switching current of the boost converters I've found...

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