Datasheet

303
2545F–AVR–06/05
ATmega48/88/168
Figure 27-2. Maximum Frequency vs. V
CC
, ATmega48V/88V/168V
Figure 27-3. Maximum Frequency vs. V
CC
, ATmega48/88/168
27.6 2-wire Serial Interface Characteristics
Table 27-2 describes the requirements for devices connected to the 2-wire Serial Bus. The ATmega48/88/168 2-wire Serial
Interface meets or exceeds these requirements under the noted conditions.
Timing symbols refer to Figure 27-4.
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
Table 27-2. 2-wire Serial Bus Requirements
Symbol Parameter
Condition Min Max Units
VIL
Input Low-voltage -0.5 0.3 V
CC
V
VIH
Input High-voltage 0.7 V
CC
V
CC
+ 0.5 V
Vhys
(1)
Hysteresis of Schmitt Trigger Inputs 0.05 V
CC
(2)
–V
VOL
(1)
Output Low-voltage 3 mA sink current 0 0.4 V
tr
(1)
Rise Time for both SDA and SCL 20 + 0.1C
b
(3)(2)
300 ns
tof
(1)
Output Fall Time from V
IHmin
to V
ILmax
10 pF < C
b
< 400 pF
(3)
20 + 0.1C
b
(3)(2)
250 ns
tSP
(1)
Spikes Suppressed by Input Filter 0 50
(2)
ns
I
i
Input Current each I/O Pin 0.1V
CC
< V
i
< 0.9V
CC
-10 10 µA