Datasheet

254
7766F–AVR–11/10
ATmega16/32U4
21.3 Typical Application Implementation
Depending on the target application power supply, the ATmega16U4/ATmega32U4 requires dif-
ferent hardware typical implementations.
Figure 21-2. Operating modes versus frequency and power-supply
21.3.1 Bus Powered device
Figure 21-3. Typical Bus powered application with 5V I/O
VCC (V)
VCC min
0
3.0
3.4
5.5
USB not operational
USB compliant,
without internal regulator
USB compliant,
with internal regulator
4.5
2.7
Max
Operating Frequency (MHz)
8 MHz
16 MHz
2 MHz
3.6
1µF
UDP
UDM
VBUS
UVSS
UID
UCAP
D-
D+
VBUS
UID
UGND
UVCC AVCC VCC
XTAL1 XTAL2 GND GND
Rs=22
Rs=22