ATmega8 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.
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
CL*VCC*f where CL = load capacitance, VCC = 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 118. Active Supply Current vs. Frequency (0.1 - 1.0 MHz)
ACTIVE SUPPLY CURRENT vs. FREQUENCY
0.1 - 1.0 MHz
3
5.5V
5.0V
2.5
4.5V
4.0V
3.3V
3.0V
2.7V
2
1.5
1
0.5
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Frequency (MHz)
244
ATmega8(L)
2486M–AVR–12/03
ATMEL [ ATMEL ]
