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I have application which requires 1 year+ operation on a small battery (2xAAA or coin cell). It will be spending 99.99% of the time sleeping only requiring an internal timer for periodic waking and wake on external interrupt. I am considering the 32 bit ARM based Arduino Due board, but nowhere can I find information on how much current the board will consume while the MCU is sleeping.

From experience with other boards, the low power capability of the MCU is negated by power regulators and power LEDs etc.

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  • \$\begingroup\$ USB circuitry also takes up some current. \$\endgroup\$ – Chetan Bhargava Feb 12 '13 at 23:29
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    \$\begingroup\$ For very low power, take a look at the MSP430. \$\endgroup\$ – Brian Drummond Feb 12 '13 at 23:42
  • \$\begingroup\$ Ultimately I'll be using an ARM Cortex-M series MCU on a custom board, but I find the Arduino environment great for quick prototyping, so I was hoping to start with the 'Due' and then migrate a custom solution using one of Atmel's or TI's ARM Cortex-M MCUs. But I will need to demonstrate µA sleep mode in operation even in the prototype. \$\endgroup\$ – jdesbonnet Feb 12 '13 at 23:54
  • \$\begingroup\$ Then perhaps use the Arduino as a starting point but be prepared to cut a few tracks here and there... \$\endgroup\$ – Brian Drummond Feb 13 '13 at 0:16
  • \$\begingroup\$ I can't imagine a Due running on a coin cell battery. Not sure how long it would last on 2 AAA batteries. What specifically is your application? \$\endgroup\$ – Chris Laplante Feb 13 '13 at 2:45
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While the processor itself supports very low-power modes the LM2734 Datasheet shows a typical quiescent current of 1.5mA. It is also only a step-down regulator so the Arduino Due shows a minimum operating voltage of 6V, but you'd really want to aim higher say by using 6 cells for 9V so it continues operating once the batteries are getting low.

If you used 6 x 1.5 AAA after a quick search the highest capacity I could spot was 1200mA/hr so that would give around 1200 / 1.5 = 800 hours or about a month of operation.

But that's only taking the main regulator into account, there's also op-amps and a secondary linear regulator along with a few resistor dividers. I do not know the exact answer but as a guestimate would say it's likely to be more in the order of 5mA (10 days of operation) and not really suitable for your intended purpose.

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