i-modul Modem 336 LL
CE/EMC Compliant Integration
10
CE/EMC Compliant Integration
When integrating the i-modul Modem 336 LL 3.0 into an application, the system
integrator is responsible for the CE/EMC conformity of the entire device. In order to
integrate the i-modul Modem 336 LL 3.0 CE and EMC compliant into your applica-
tion, we recommend the following for you to observe during development.
10.1
Your Application
The motherboard for the i-modul must be designed according to the
applicable CE/EMC guidelines. Always observe short signal lines and
sufficient ground surface.
Connect the i-modul with a conducting spacer bolt to the device ground.
If you develop a platform, which is compatible with several, different i-
moduls, you must maintain the respective design criteria for each i-modul
(especially concerning the phone connection).
The PCB tracks to the i-moduls with network interfaces, like Modem, ISDN,
and Ethernet, must be designed with a track distance of 2.5 mm between
the tracks of the network interface and all other signals (refer to EN60950).
10.2
Application Interface / Terminal Strip P1
The TTL RS232 interface should be equipped with ferrite beads directly at
the module to reduce interference signals from the motherboard.
It is also beneficial to design capacitors (preferably SMD) at all RS232 and
I/O signal lines to GND, which can be equipped when needed. Short lines to
the connector and good ground are important. The recommended value for
capacitors is 22 pF to 47 pF.
10.3
Network Interface / Terminal Strip P2 (for Modem
/ISDN)
The line to the network interface (line from i-modul to device socket) should
be as short as possible and not be routed close to sources of interference
(e.g. switching power supplies).
Provide the line with ferrite beads directly at the device socket.
The phone interface (not for i-modul with Ethernet interface) should be
provided with standard ferrite beads (e.g. Murata BLM31A601SPT or Würth
Elektronik type 74279213) and with optional ceramic capacitors
(100 pF/2 kV, Y2 standard) to ground.
In case of extended requirements to the interference resistance of the phone
line (especially burst), a current compensated impedance (e.g. Epcos
B82790-C2475-N340 or Würth Elektronik type 744202) can be used.
The strip conductors on the Ethernet side should have a wide design
(minimum 24 mil).
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