Datasheet

390
ATmega640/1280/1281/2560/2561
2549K–AVR–01/07
Typical Characteristics
The following charts show typical behavior. These figures are not tested during manu-
facturing. 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
registers set and thus, the corresponding I/O modules are turned off. Also the Analog
Comparator is disabled during these measurements. Table 181 on page 395 and Table
182 on page 396 show the additional current consumption compared to I
CC
Active and
I
CC
Idle for every I/O module 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 identi-
cal 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 52 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 temperature. The dominating factors are operating voltage and frequency.
The current drawn from capacitive loaded pins may be estimated (for one pin) as
C
L
*V
CC
*f where C
L
= load capacitance, V
CC
= operating voltage and f = average switch-
ing frequency of I/O pin.
The parts are characterized at frequencies higher than test limits. Parts are not guaran-
teed 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 dif-
ferential current drawn by the Watchdog Timer.
Active Supply Current Figure 167. Active Supply Current vs. frequency (0.1 - 1.0 MHz)
ACTIVE SUPPLY CURRENT vs. FREQUENCY
0.1 - 1.0 MHz
5.5V
5.0V
4.5V
4.0V
3.3V
2.7V
1.8V
0
0,5
1
1,5
2
2,5
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Frequency (MHz)
I
CC
(m
A
)