DIGITAL-LOGIC AG MSM586SEN/SEV Manual V1.5E
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2.12 High frequency radiation (to meet EN55022 & EN61000)
Since the PC/104 CPU modules are very high integrated embedded computers, no peripheral lines are pro-
tected against the radiation of high frequency spectrum. To meet a typical EN55022 requirement, all periph-
erals, they are going outside of the computer case, must be filtered externaly.
Typical signals, they must be filtered:
Keyboard: KBCLK, KBDATA, VCC
Mouse: MSCLK, MSDATA, VCC
COM1/2/3/4: All serial signals must be filtered
LPT: All parallel signals must be filtered
CRT: red,blue,green, hsynch, vsynch must be filtered
Typical signals, they must not be filtered, since they are internaly used:
IDE: connected to the harddisk
Floppy: connected to the floppy
LCD: connected to the internal LCD
1. For peripheral cables:
Use for all DSUB connector a filtered version. Select carefully the filter specifications.
Place the filtered DSUB connector directly frontside and be shure that the shielding makes
a good contact with the case.
9pin DSUB connector from AMPHENOL: FCC17E09P 820pF
25pin DSUB connector from AMPHENOL: FCC17B25P 820pF
2. For stackthrough applications:
Place on each peripheral signal line, they are going outside, a serial inductivity and
after the inductivity a capacitor of 100pF to 1000pF to ground.
In this case, no filtered connectors are needed. Place the filter directly under or
behind the onboard connector.
Serial Inductivity: TDK HF50ACB321611-T 100Mhz, 500mA, 1206 Case
Ground capacitor: Ceramic Capacitor with 1000pF
Power supply:
Use a currentcompensated dualinductor on the 5V supply
SIEMENS B82721-K2362-N1 with 3.6A , 0.4mH
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