Allowed current thru AVR devices

I can't find where I posted this previously, as it comes up occasionally I thought I would re-post it. Summary: 200mA allowed per VCC pin, and not a total limit on the part.

February 2013

Hello Atmel technical team, I have a question regarding power utilization in ATmega328P, ATmega1284P, ATmega2560 devices.

The ATmega328P, ATmega1284P, ATmega2560 data sheets all show:

Absolute Max for DC current VCC and GND pins............. 200.0mA.

The Electrical characteristics all show greater then 200mA total being supported by the ports with various current limits per port.

(port notes not copied here)

My interpretation of these notes is that:

for the '328P the sum of current across the VCC/AVCC pins can support the current thru the ports, with 400mA max thru the VCC/AVCC & Gnd pins and 300mA thru the ports, (altho SMD parts have an extra VCC& Gnd pin, so 600mA could be taken in)

for the '2560 the sum of current across the VCC/AVCC pins can support the current thru the ports, with 1000mA max thru the VCC/AVCC & Gnd pins and 800mA thru the ports,

and for the '1284P the sum of current across the VCC/AVCC pins can support the current thru the ports, with 400mA max thru the VCC/AVCC & Gnd pins and 200mA thru the ports (altho SMD parts have 4 each VCC/AVCC & Gnd pins, so 800mA could be taken in) So the '1284 seems to be under supported for IO current. But a nice chip none the less that I will continue to use.

Can you confirm that for 328s & 2560s that the higher currents in the notes are supported and the 200mA Absolute Max is for each individual VCC/Gnd pin and Not for the entire device?

Atmel's Response: Thank you for contacting Atmel Technical support.

The 200mA is the absolute maximum current rating of the power supply pin. Whatever may be the power supply voltage (The power supply voltage should be within the specification), the current through the Vcc pin should not exceed 200mA.

Also the 200mA specification under the absolute maximum rating is for individual Vcc pin. And the AVCC pins should not be considered along with the VCC pins for the total absolute maximum rating. Hence, for the device ATmega1284P, for the DIP package, the maximum current rating will be 200mA, whereas for the TQFP package, the max. current rating will be 600mA.

For 328P, the max current rating is 400mA for the TQFP package. For ATmega2560, the max current rating is 800 mA. Also, please note that this is absolute maximum rating and exposing the device to absolute maximum conditions for longer duration of time could possibly cause damage to the device.

Hope this clarifies. Please get back to us in case of further queries.

Best Regards, Ineyaa N Atmel Technical Support Team

Thanks!

I was right! :)

Awesome post CrossRoads!! I think you should post this in the playground and keep a link to it handy..

I cannot access the playground, except at night. Will post if I can remember.

I would be careful with that info, especially considering a typical arduino user. 2W or 4W loss @5V is way too much for those smd chips. I would recommend max 20% of maximum ratings though.

20% of maximum? So you'd recommend 40mA on the supply pins? That is a bit restrictive.