Specifications

WM_PRJ_Q2501_PTS_002 - 001
March 2004
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4.2.2.2 Application Ground Plane and Shielding connection
The WISMO Quik Q2501 module shielding case is linked to the ground. The
ground has to be connected on the mother board through a complete layer on
the PCB.
A ground plane must be available on the application board to provide efficient
connection to the module shielding:
 The bottom side shielding of the WISMO module is achieved through
the top cold rolled steel cover connected to the internal ground plane of
the module. This one is connected through the shielding to the
application ground plane.
Best shielding performance will be achieved if the application ground plane is a
complete layer of the application PCB:
 To ensure a good shielding of the module, a complete ground plane
layer on the application board must be available, with no trade-off.
Connections between other ground planes shall be done with vias.
Without this ground plane, external Tx spurious or Rx blockings could appear.
4.2.3 SIM interface routing constraints
 For the SIM interface, length of the tracks between the WISMO module
and the SIM socket should be as short as possible. Maximum length
recommended is 10 cm.
 ESD protection is mandatory on the SIM lines if access from outside of
the SIM socket is possible.
 The capacitor on SIM_VCC signal (100 nF) must be placed as close as
possible to the DALC208SC6 component on the PCB (refer to paragraph
3.3.4).
4.2.4 Audio circuit routing constraints
To get better acoustic performances, basic recommendations are the
followings:
 The speaker lines (SPKxx) must be routed in parallel, without any wire
in between.
 The microphone lines (MICxx) must be routed in parallel, without any
wire in between.
All the filtering components (RLC) must be placed as close as possible to the
associated MICxx and SPKxx pins.