High Frequency Radiation (To Meet En55022); For Peripheral Cables; For Stack-Through Applications; Power Supply - DIGITAL-LOGIC MSM800SEV/SEL Technical User's Manual

DIGITAL-LOGIC AG

2.12. High Frequency Radiation (to meet EN55022)

Since the PC/104 CPU modules are very highly integrated embedded computers, peripheral lines are not
protected against radiation from the high frequency spectrum. To meet a typical EN55022 requirement, all
peripherals that go outside of the computer case must be externally filtered.
Typical signals that must be filtered:
Keyboard:
Mouse:
COM1/2/3/4:
LPT:
CRT:
Typical signals that must not be filtered, since they are used internally:
IDE:
Floppy:
LCD:

2.12.1. For Peripheral Cables:

Use a filtered version for all DSUB connectors. Select the filter specifications carefully. Place the filtered
DSUB connector directly on the front side and be sure that the shielding makes good contact with the case.
9pin DSUB connector from AMPHENOL:
25pin DSUB connector from AMPHENOL:

2.12.2. For Stack-Through Applications:

On each peripheral signal line that goes outside the computer case, place a serial inductivity followed by a
grounded capacitor of 100pF to 1000pF. In this case, no filtered connectors are needed. Place the filter
directly under or behind the onboard connector.
Serial Inductivity:
Ground Capacitor:

2.12.3. Power Supply:

Use a current-compensated dual inductor on the 5V supply.
SIEMENS B82721-K2362-N1
KBCLK, KBDATA and VCC
MSCLK, MSDATA and VCC
All serial signals must be filtered
All parallel signals must be filtered
Red, blue, green, hsynch and vsynch must be filtered
Connected to the hard disk
Connected to the floppy
Connected to the internal LCD
TDK HF50ACB321611-T
Ceramic Capacitor with 1000pF
with 3.6A, 0.4mH
MSM800SEV/SEL/BEV/XEV/XEL Detailed Manual V1.7
FCC17E09P
FCC17B25P
39
820pF
820pF
100MHz, 500mA, 1206 Case