Datasheet

33.5 Clock Characteristics
33.5.1 Calibrated Internal RC Oscillator Accuracy
Table 33-4. Calibration Accuracy of Internal RC Oscillator
Frequency V
CC
Temperature Calibration Accuracy
Factory
Calibration
8.0 MHz 2.7V - 4.2V 0°C to +50°C ±2%
8.0 MHz 1.8V - 5.5V 0°C to +70°C ±3.5%
8.0 MHz 1.8V - 5.5V -40°C to +105°C ±5%
User
Calibration
7.3 - 8.1 MHz 1.8V - 5.5V -40°C to - 85°C ±1%
Note:
1. Accuracy of oscillator frequency at calibration point, fixed temperature and fixed voltage.
33.5.2 External Clock Drive Waveforms
Figure 33-2. External Clock Drive Waveforms
V
IL1
V
IH1
33.5.3 External Clock Drive
Table 33-5. External Clock Drive
Symbol Parameter V
CC
= 1.8 - 5.5V V
CC
= 2.7 - 5.5V V
CC
= 4.5 - 5.5V Units
Min. Max. Min. Max. Min. Max.
1/t
CLCL
Oscillator Frequency 0 4 0 10 0 20 MHz
t
CLCL
Clock Period 250 - 100 - 50 - ns
t
CHCX
High Time 100 - 40 - 20 - ns
t
CLCX
Low Time 100 - 40 - 20 - ns
t
CLCH
Rise Time - 2.0 - 1.6 - 0.5 μs
t
CHCL
Fall Time - 2.0 - 1.6 - 0.5 μs
Δt
CLCL
Change in period from one clock
cycle to the next
- 2 - 2 - 2 %
ATmega328PB
Electrical Characteristics
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001906C-page 409