Sierra Wireless AirPrime SL808 Series, Product Technical Specification & Customer Design Manuallines, Page: 45 / 122

Rev 1 Dec.10 Proprietary and Confidential - Specifications subject to change 45
4.7.1 USB pin descriptions
Table 4-13 describes the UART1 interface pins.
See Digital I/O electrical information on page 39 for 1V8 voltage characteristics
and reset state definitions.
4.7.2 Electrical characteristics
Table 4-14 describes the USB interface’s electrical characteristics.
4.7.3 Application notes
See Reference schematic on page 40 for an implementation of the USB interface.
4.7.4 Host-developed USB drivers
Note: If you are using Sierra Wireless drivers, you can skip this section—it is intended for
developers who are creating their own USB drivers.
Detailed USB driver specifications for Sierra Wireless AirPrime modules are
included in the AirCard/AirPrime USB Driver Developer’s Guide, available from
your Sierra Wireless account representative.
Table 4-13: USB interface pins
Pin Signal I/O
type
Reset
state
a
Description Notes
50 USB_D+ HS-USB data +
•
Protected against ± 500V Human Body Model
ESD.
•
ESD suppressor with shunt capacitance <1 pF
is recommended.
•
Host must ensure D+ and D- traces are well
matched and of differential impedance of 90
Ω .
All high-speed differential routing techniques
should be applied.
•
Allocate room to accommodate a common-
mode choke filter (90

impedance) between
the module and destination
51 USB_D- HS-USB data -
a. See Table 4-4 on page 40 for state definitions.
Table 4-14: USB interface electrical characteristics
Parameter Minimum Typical Maximum Unit
USB_D+
USB_D-
3 3.3 3.6 V