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AN901

APPLICATION NOTE

EMC GUIDELINES FOR

MICROCONTROLLER-BASED APPLICATIONS

by Microcontroller Division Applications

INTRODUCTION

Electromagnetic compatibility (EMC) must be taken into account at the very beginning of a

project as the cost of correcting an EMC problem encountered at the start of production can be

far greater that the cost of a detailed EMC study during the development phase of an applica-

tion.

The use of microcontroller-based systems is increasingly wide-spread, especially in such

areas as consumer, industrial and automotive applications, where the drive for cost reduction

is the common trend. This emphasis on cost reduction and the increasing complexity of such

systems requires the manufacturers of semiconductor components to develop highly inte-

grated, single chip, high operating frequency microcontrollers using the highest density tech-

nology possible. Unfortunately, for semiconductor structures, the higher the density and the

faster the operation, intrinsically the higher the level of electrical noise generated, and the in-

creased sensitivity to spikes induced from external noise. Therefore, the PCB layout, the soft-

ware and the system must now apply EMC “hardening” techniques in their design.

This note aims to provide guidelines for designers of microcontroller-based applications so

that the optimum level of EMC performances can be achieved.

For general information about EMC performances, please refer to application note AN898.

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