![Siemens MC45 Скачать руководство пользователя страница 56](http://html.mh-extra.com/html/siemens/mc45/mc45_manual_375436056.webp)
MC45 Hardware Interface Description
P R E L I M I N A R Y
MC45_HD_01_V00.02a
Page 56 of 90
12.08.2002
3.7.3 Grounding the SIM interface
To ground the SIM interface you can proceed from several approaches, depending on your
individual application design. The following information is just one of several options you can
apply:
Potential equalization can best be achieved by applying a separate ground for the SIM
interface. For example, the PCB of your application platform may be designed to include an
extra ground plane for the SIM card reader, rather than connecting the CCGND pin of the
board-to-board connector to the central ground on your application platform. For the SIM
card ground plane, you can choose a capacitive or inductive coupling or a zero Ohm bridge.
Often, a combination of capacitive and inductive coupling will yield best results.
It depends on your actual layout where to place these lines. For ease of planning and
designing, you can simply place the required footprints at each side of the ground plane.
This gives you the flexibility, when you test your equipment for ESD and EMC protection, to
decide which of them to use, if at all.
Figure 21: Connecting a separate ground for SIM interface
GSM engine
GND
GND
GND
Ground plane
Insulation
GND
Customer
application
CCGND
SIM card
reader
CCGND
CCGND
B
2B
c
onne
ct
or
Notes:
This figure is only a
simplified example
to give you an idea
where to place the
lines.
One capacitive /
inductive coupling
will do, if needed at
all.