AN898 Datasheet, PDF (1/4 Pages) STMicroelectronics – EMC GENERAL INFORMATION

AN898
APPLICATION NOTE
EMC GENERAL INFORMATION
by Microcontroller Division Applications
INTRODUCTION
Because many electronic circuits are in proximity to each other, it is essential that their design
is not affected by external noise sources and that the circuit itself is not a noise source af-
fecting other circuits. This relationship is known as electromagnetic compatibility or EMC.
Sources of electromagnetic noise are numerous and have both natural and man-made ori-
gins.
Natural sources below 10 MHz are dominated by the atmospheric noise generated by elec-
trical storms. Above 10 MHz, natural sources consist primarily of cosmic noise and solar radi-
ation.
Man-made noise include AM, FM, TV and other broadcast transmitters, mobiles radios but
also computing devices, motors, appliances, power lines, auto ignition systems and many
others. With the proliferation of these sources (particularly in urban areas), electromagnetic
noise has reached important levels.
For detailed information regarding EMC guidelines for microcontroller - based applications,
please refer to AN901.
Figure 1. Electromagnetic Radiation Sources
ELECTROMAGNETIC RADIATION
NATURAL ORIGIN
MAN-MADE ORIGIN
AN898/1100
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