Datasheet

271
ATmega48PA/88PA/168PA [DATASHEET]
9223F–AVR–04/14
29.4 Clock Characteristics
29.4.1 Calibrated Internal RC Oscillator Accuracy
29.4.2 External Clock Drive Waveforms
Figure 29-2. External Clock Drive Waveforms
29.4.3 External Clock Drive
Table 29-3. Calibration Accuracy of Internal RC Oscillator
Frequency V
CC
Temperature Calibration Accuracy
Default 3V Factory
Calibration
8.0MHz
3V 25°C ±1%
2.7V to 5.5V –40°C to 125°C ±14%
5V Factory
Calibration
8.0MHz
5V 25°C ±1%
4.5V to 5.5V –40°C to 125°C ±10%
Watchdog Oscillator 128kHz 2.7V to 5.5V –40°C to 125°C ±40%
t
CHCX
V
IH1
V
IL1
t
CHCX
t
CLCH
t
CHCL
t
CLCX
t
CLCL
Table 29-4. External Clock Drive
Parameter Symbol
V
CC
= 2.7 - 5.5V V
CC
= 4.5 - 5.5V
UnitMin. Max. Min. Max.
Oscillator frequency 1/t
CLCL
0 8 0 16 MHz
Clock period t
CLCL
125 62.5 ns
High time t
CHCX
50 25 ns
Low time t
CLCX
50 25 ns
Rise time t
CLCH
1.6 0.5 µs
Fall time t
CHCL
1.6 0.5 µs
Change in period from one clock
cycle to the next
t
CLCL
2 2 %
Note: All DC characteristics contained in this datasheet are based on simulation and characterization of other AVR microcon-
trollers manufactured in the same process technology. These values are preliminary values representing design
targets, and will be updated after characterization of actual silicon.