Datasheet

33.3 Speed Grades
Maximum frequency is dependent on V
CC.
As shown in the figure Maximum Frequency vs. V
CC
, where
the curve is linear between 1.8V < V
CC
< 2.7V and between 2.7V < V
CC
< 4.5V.
Figure 33-1. Maximum Frequency vs. V
CC
4MHz
1.8V 2.7V 4.5V
10MHz
20MHz
5.5V
Safe Operating Area
33.4 Clock Characteristics
Related Links
13.6 Calibrated Internal RC Oscillator
13.12.1 OSCCAL
33.4.1 Calibrated Internal RC Oscillator Accuracy
Table 33-6. Calibration Accuracy of Internal RC Oscillator
Frequency V
CC
Temperature Calibration Accuracy
Factory
Calibration
8.0 MHz 3.0V 25°C ±10%
User
Calibration
Fixed frequency within:
7.3 - 8.1 MHz
Fixed voltage within:
1.8V - 5.5V
Fixed temperature within:
-40°C to - 85°C
±1%
Related Links
13.12.1 OSCCAL
33.4.2 External Clock Drive Waveforms
Figure 33-2. External Clock Drive Waveforms
V
IL1
V
IH1
Related Links
ATmega48A/88A/168A
Electrical Characteristics
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Datasheet Complete
DS40002007A-page 387