Magnetic beads are specifically designed to suppress high-frequency noise and peak interference on signal and power lines, and also have the ability to absorb electrostatic pulses. Magnetic beads are used to absorb Super high frequency signals. For example, some RF circuits, PLLs, oscillation circuits, and Super high frequency memory circuits (DDRSDRAM, RAMBUS, etc.), magnetic beads need to be added to the power input part. Inductors are energy storage elements, which are used in LC oscillation circuits, medium and low frequency filter circuits, etc., and their application frequency range rarely exceeds 50 MHz.

The main function of magnetic beads is to eliminate RF noise present in transmission line structures (circuits). RF energy is the AC sine wave component superimposed on the DC transmission level, and the DC component is the useful signal required. However, RF energy is useless electromagnetic interference transmitted and radiated along the line (EMI). To eliminate these unnecessary signal energy, chip magnetic beads are used to act as high-frequency resistors (attenuators), which allow DC signals to pass through while filtering out AC signals. Usually, high-frequency signals are above 30MHz, however, low-frequency signals are also affected by chip magnetic beads.

Magnetic beads have high resistivity and permeability, which are equivalent to series connection of resistance and inductance, but both resistance and inductance values vary with frequency. It has better high-frequency filtering characteristics than ordinary inductors and exhibits resistance at high frequencies, so it can maintain a high impedance over a relatively wide frequency range, thereby improving the frequency modulation filtering effect.