C8051T620/1/6/7 & C8051T320/1/2/3
20
Rev. 1.2
Figure 1.5. Typical Bus-Powered Connections
VREGIN
VBUS
VDD
D+
D-
GND
RST/
C2CK
E
S
D
P
rot
e
ct
ion
US
B
C
onn
e
ct
or
A 1-5 kohm pull-up resistor can
be connected to VIO* for added
noise immunity.
1-5
kohm
RESET SIGNAL
SUPPLY NET
USB
Add decoupling/bypass
capacitors close to each
voltage supply pin.
0.1µF
4.7µF
1µF
Add ESD protection
diodes designed for
use with USB, such
as Littlefuse
SP0503BAHT or
equivalent.
1.8V to VDD
VIO*
VIO can be connected directly
to VDD.
VIO*
Po
rt
I/
O
GPIO
DEBUG SIGNALS
Connections needed for
optional debug interface
Keep the USB shield ground
isolated from the device ground.
C2CK
C2D
GND
Unused port pins should be left
floating, configured to push-pull
output, and driven high.
GND
C2D
*Note : VIO only appears on certain package options. If VIO is not present, the RST pullup can connect to VDD.