Datasheet

Table 59-10. USB Interface Checklist
Signal
Name
Recommended Pin Connection Description
D+ • The impedance of the pair should be matched on the PCB to
minimize reflections.
• USB differential tracks should be routed with the same
characteristics (length, width, number of vias, etc.)
• For a tightly coupled differential pair,the signal routing should be
as parallel as possible, with a minimum number of angles and
vias.
USB full speed / low
speed positive data
upstream pin
D- USB full speed / low
speed negative data
upstream pin
Figure 59-17. Low Cost USB Interface Example Schematic
VBUS
USB
Connector
VBUS
D+
D-
GND
Shield
GND (Board)
USB_D+
USB_D-
USB
Differential
Data Line Pair
It is recommended to increase ESD protection on the USB D+, D-, and VBUS lines using dedicated
transient suppressors. These protections should be located as close as possible to the USB connector to
reduce the potential discharge path and reduce discharge propagation within the entire system.
The USB FS cable includes a dedicated shield wire that should be connected to the board with caution.
Special attention should be paid to the connection between the board ground plane and the shield from
the USB connector and the cable.
Tying the shield directly to ground would create a direct path from the ground plane to the shield, turning
the USB cable into an antenna. To limit the USB cable antenna effect, it is recommended to connect the
shield and ground through an RC filter.
Figure 59-18. Protected USB Interface Example Schematic
4.5nF
1MΩ
VBUS
USB
Connector
VBUS
D+
D-
GND
Shield
USB Transient
protection
RC Filter
(GND/Shield
Connection)
GND (Board)
USB_D+
USB_D-
USB
Differential
Data Line Pair
SAM D5x/E5x Family Data Sheet
Schematic Checklist
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 2110