Behind the Magic of High Frequency SMT Chip Bead Ferrites


Technology is advancing at a tremendous rate and the next generation of devices are shifting towards wireless applications. The movement towards higher frequency, into the gigahertz range has begun and more knowledge of components in these applications is desired. EMC continues to grow in importance and there is a demand to know the characteristics of EMC components used beyond their current typical application range. The goal of this application note is to explain the different properties between multilayer ferrite beads in high frequency (WE-CBF HF) and standard multilayer ferrite beads (WE-CBF), as well as a new methodology developed at Würth Elektronik for the measurement of DC bias at high frequencies. Lastly, some uncommon applications, where the WE-CBF HF high frequency series are a suitable alternative to traditional design topologies are shown.

Chip bead ferrites are one of the most used components for suppressing high frequency noise in the electronics industry. They are passive components with a high attenuation over a wide frequency range, and at the same time do not influence the useful component of the signal. They are commonly connected in series with the power supply or signal source. Nevertheless, improper use of the ferrite bead in the system can degrade the overall EMI suppression capability.

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