Datasheet

167
2586D–AVR–02/06
ATtiny25/45/85
24.4 External Clock Drive
24.5 Maximum Speed vs. V
CC
Figure 24-2. Maximum Frequency vs. V
CC
Figure 24-3. Maximum Frequency vs. V
CC
Table 24-1. External Clock Drive
Symbol Parameter
V
CC
= 1.8 - 5.5V V
CC
= 2.7 - 5.5V V
CC
= 4.5 - 5.5V
UnitsMin. Max. Min. Max. Min. Max.
1/t
CLCL
Clock 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
∆t
CLCL
Change in period from one clock cycle to the next 2 2 2 %
10 MHz
4 MHz
1.8V 2.7V 5.5V
Safe Operating Area
20 MHz
10 MHz
2.7V 4.5V 5.5V
Safe Operating Area