Sim Interface; Audio Circuit; Rf Circuit - Sierra Wireless AirPrime SL808 Series Product Technical Specification & Customer Design Manuallines

Product Technical Specification & Customer Design Guidelines
98 Proprietary and Confidential - Specifications subject to change
A ground plane must be available on the application board to provide efficient
connection to the bottom ground of the AirPrime SL808X Embedded Module. The
bottom side shielding of the AirPrime SL808X Embedded Module is achieved by
soldering the ground plane of the application board and the AirPrime SL808X
Embedded Module.
The best shielding performance is achieved when the application ground plane is
a complete layer of the application PCB. To ensure good shielding of the AirPrime
SL808X Embedded Module, a complete ground plane layer on the application
board must be available, with no tradeoffs. Connections between other ground
planes should be done with bias.
Without this ground plane, external spurious TX or RX blockings could appear.
For more information, see

8.7.2 SIM interface

The length of the tracks between the AirPrime SL808X Embedded Module and
the SIM socket should be as short as possible. Maximum recommended length is
10cm.
ESD protection is mandatory on the SIM lines if access from outside of the SIM
socket is possible.
The capacitor (100 nF) on the EXT_VREG_USIM signal must be placed as close
as possible to the DALC208SC6 component on the PCB (see
page 42).

8.7.3 Audio circuit

To get better acoustic performances, the basic recommendations are as follows:
• The speaker lines (SPK) must be routed in parallel without any wires in
between
• The microphone lines (MIC) must be routed in parallel without any wires in
between
All the filtering components (RLC) must be placed as close as possible to the
associated MIC and SPK pins.

8.7.4 RF circuit

The RF signal must be routed on the application board using tracks with a 50
characteristic impedance.
Basically, the characteristic impedance depends on the dielectric, the track width
and the ground plane spacing.
In order to respect this constraint, Sierra Wireless recommends using MicroStrip
or StripLine structure and computing the Tracks width with a simulation tool (like
AppCad shown in the figure below and that is available free of charge at
http://www.agilent.com).
Recommended PCB landing pattern on page 96.
SIM interface on
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