Wirewound Ferrite Beads SMB3H

SMB3H Family

Multiline Suppressor Beads

Ferrite Beads—especially the Wirewound Ferrite Bead and Surface Mount Device (SMD) Ferrite Bead variants—are essential components in modern electromagnetic compatibility (EMC) solutions. These passive magnetic devices serve as high-frequency noise suppressors by leveraging frequency-dependent impedance characteristics of ferrite materials. The SMB3H family delivers optimized EMI filtering performance across a broad spectrum, making it ideal for applications where signal integrity and circuit stability are critical.

Working Principle

1. Frequency-dependent impedance:
At low frequencies, ferrite beads behave like minimal-loss inductors, allowing DC or low-frequency signals to pass with negligible attenuation. As frequency increases, the core material’s magnetic permeability shifts, inducing eddy current losses that manifest as resistive impedance. This property makes them indispensable in EMI suppression filters designed for switching power supplies, digital circuits, and RF-sensitive systems.

2. EMI suppression:
By converting unwanted high-frequency energy into heat, ferrite beads effectively reduce conducted emissions without interfering with intended low-frequency operation. Both wirewound and SMD configurations offer tailored performance for different board layouts and thermal constraints. Their compact design supports integration into space-constrained electronic assemblies such as consumer electronics, industrial controls, and automotive systems.

3. Equivalent Circuit Model:
In practical filter designs, ferrite beads can be modeled as a series RLC network—a resistor representing lossy behavior, an inductor providing inductive reactance at higher frequencies, and parasitic capacitance affecting ultra-high-frequency response. This model guides engineers in selecting the right bead for specific applications, including those requiring broadband noise reduction or targeted harmonic filtering in power delivery networks.

Series in this family