Introduction

Modern medical devices are packed with electronics, ranging from sensitive analog amplifiers to sophisticated microprocessors. Unfortunately, these same devices can be adversely affected by Electromagnetic Interference (EMI) problems. Furthermore, these EMI problems can be compounded due to critical missions and harsh EMI environments. Designers and users of modern medical devices need to know how to identify, prevent, and fix these EMI problems. The leakage current limit is the single most important EMI–related concern in medical device design because it is almost impossible to adequately filter signal and power lines given the current limit. This major design challenge essentially mandates that EMI issues be addressed from the very start of a design project. Designers need also be aware that medical devices will soon be subject to new EMI regulations in Europe, and that similar requirements may be implemented in the United States. As currently proposed, these requirements reflect the real operating environment, providing helpful guidance for designers.