TOBY-L1 and MPCI-L1 series - System Integration Manual
UBX-13001482 - R04
Advance Information
Design-in
Page 59 of 90
2.6
Data communication interfaces
2.6.1
Universal Serial Bus (USB)
2.6.1.1
Guidelines for USB circuit design
The
USB_D+
and
USB_D-
lines carry the USB serial data and signaling. The lines are used in single ended mode
for full speed signaling handshake, as well as in differential mode for high speed signaling and data transfer.
USB pull-up or pull-down resistors on
USB_D+
and
USB_D-
as required by the
Universal Serial Bus Revision 2.0
are part of the USB pad driver and do not need to be externally provided.
External series resistors on
USB_D+
and
USB_D-
as required by
Universal Serial Bus Revision 2.0 specification
are also integrated and do not need to be externally provided.
Typical USB connection circuits are illustrated in Figure 33.
The USB interface pins ESD sensitivity rating is 1 kV (Human Body Model according to JESD22-A114F).
Higher protection level could be required if the lines are externally accessible on the application board.
Higher protection level can be achieved by mounting a very low capacitance (i.e. less or equal to 1 pF) ESD
protection (e.g. Tyco Electronics PESD0402-140 ESD protection device) on the lines connected to these
pins, close to accessible points.
The
USB_D+
and
USB_D-
pins of the modules can be directly connected to the USB host application processor
without additional ESD protections if they aren’t externally accessible or according to EMC/ESD requirements.
TOBY-L1 series
D+
D-
GND
28
USB_D+
27
USB_D-
GND
USB DEVICE
CONNECTOR
D1
D2
VBUS
TOBY-L1 series
D+
D-
GND
28
USB_D+
27
USB_D-
GND
USB HOST
PROCESSOR
MPCI-L1 series
D+
D-
GND
38
USB_D+
36
USB_D-
GND
USB DEVICE
CONNECTOR
D1
D2
VBUS
MPCI-L1 series
D+
D-
GND
38
USB_D+
36
USB_D-
GND
USB HOST
PROCESSOR
Figure 33: USB Interface application circuit
Reference
Description
Part Number - Manufacturer
D1, D2
Very Low Capacitance ESD Protection
PESD0402-140 - Tyco Electronics
Table 20: Component for USB application circuit