Datasheet

386
ATmega16U4/32U4 [DATASHEET]
Atmel-7766J-USB-ATmega16U4/32U4-Datasheet_04/2016
29.5 System and Reset Characteristics
The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling).
29.6 Maximum speed vs. V
CC
Maximum frequency is depending on V
CC.
As shown in Figure 29-2 on page 386, the Maximum Frequency vs.
V
CC
curve is linear between 2.7V < V
CC
< 5.5V.
Figure 29-2. Maximum Frequency vs. V
CC
29.7 2-wire Serial Interface Characteristics
The following table describes the requirements for devices connected to the 2-wire Serial Bus. The device 2-wire Serial
Interface meets or exceeds these requirements under the noted conditions.
Timing symbols refer to Figure 29-3 on page 388.
Table 29-3. Reset and Brown-out Detection Characteristics
Symbol Parameter Condition Min. Typ. Max. Units
V
POT
Power-on Reset Threshold Voltage (rising) 1.4 2.3 V
Power-on Reset Threshold Voltage (falling)
()
1.3 2.3 V
V
POR
V
CC
Start Voltage to ensure internal Power-on Reset signal -0.1 +0.1 V
V
CCRR
V
CC
Rise Rate to ensure internal Power_on Reset signal 0.3 V/ms
V
RST
RESET Pin Threshold Voltage 0.2V
CC
0.85V
CC
V
t
RST
Minimum pulse width on RESET Pin 5V, 25°C 400 ns
2.7V 4.5V 5.5V
Safe Operating Area
16 MHz
8 MHz