Datasheet

338
7674F–AVR–09/09
ATmega164P/324P/644P
27. ATmega644P 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.
• 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 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
current drawn by the Watchdog Timer.
Figure 27-1. Active Supply Current vs. Frequency (0.1 - 1.0 MHz)
ACTIVE S UP P LY CURRENT vs . LOW FRE QUE NCY
Temperature = 125˚C
5.5 V
5.0 V
4.5 V
3.3 V
3.0 V
2.7 V
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Frequency (MHz)
I
CC
(mA)