Mega2560 power consumption

Forum 2005-2010 (read only) Hardware Troubleshooting
1

Hi,

I could not find this information. What is the consumption of Mega2560? I measure about 200 mA flowing between 12 V supply and Mega's power connector (nothing connected to pins, "blink" example uploaded). Is this expected?

Thank you.

2

Look up the Atmel datasheet for the ATmega2560, they have graphs for current consumption v. clock frequency somewhere.

Also are the inputs floating? There's a lot of pins and if they are all floating that could contribute quite a lot of current.

3

Thanks. I checked http://www.atmel.com/dyn/resources/prod_documents/doc2549.PDF section 30. Electrical Characteristics and found this maximum rating:
DC Current VCC and GND Pins................................ 200.0 mA
Below this table follow another one with Power Supply Current but the stated values are 14 mA max.

Strange.

4

DC Current VCC and GND Pins................................ 200.0 mA

This maximum current spec combines internal consumption for the chip AND any and all current being drawn from the output pins powering external loads like LEDs, etc.

Lefty

5

I measure about 200 mA flowing between 12 V supply and Mega's power connector (nothing connected to pins, "blink" example uploaded).

200mA sounds a lot to me too. Wondering if you are not measuring the board power consumption, including the power régulator. Especially if the onboard power is 5V and the external power source is 12V, as converter efficiency can be as low as 55%.

Suggestion: measure using a 5V external power supply, bypassing the regulator (for instance powering through USB port).