ATmega640/1280/1281/2560/2561
32. Typical Characteristics
The following charts show typical behavior. These figures are not tested during manufacturing.
All current consumption measurements are performed with all I/O pins configured as inputs and
with internal pull-ups enabled. A sine wave generator with rail-to-rail output is used as clock
source.
All Active- and Idle current consumption measurements are done with all bits in the PRR regis-
ters set and thus, the corresponding I/O modules are turned off. Also the Analog Comparator is
disabled during these measurements. Table 32-1 on page 393 and Table 32-2 on page 393
show the additional current consumption compared to ICC Active and ICC Idle for every I/O mod-
ule controlled by the Power Reduction Register. See “When the SM2:0 bits are 111 and an
external crystal/resonator clock option is selected, the SLEEP instruction makes the MCU enter
Extended Standby mode. This mode is identical to Power-save mode with the exception that the
Oscillator is kept running. From Extended Standby mode, the device wakes up in six clock
cycles.Power Reduction Register” on page 54 for details.
The power consumption in Power-down mode is independent of clock selection.
The current consumption is a function of several factors such as: operating voltage, operating
frequency, loading of I/O pins, switching rate of I/O pins, code executed and ambient tempera-
ture. The dominating factors are operating voltage and frequency.
The current drawn from capacitive loaded pins may be estimated (for one pin) as CL*VCC*f where
CL = load capacitance, VCC = operating voltage and f = average switching frequency of I/O pin.
The parts are characterized at frequencies higher than test limits. Parts are not guaranteed to
function properly at frequencies higher than the ordering code indicates.
The difference between current consumption in Power-down mode with Watchdog Timer
enabled and Power-down mode with Watchdog Timer disabled represents the differential cur-
rent drawn by the Watchdog Timer.
387
2549L–AVR–08/07
ATMEL [ ATMEL ]
