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The connection and difference between inductance and magnetic beads

Release time: 2023-07-20


inductance and magnetic bead

1, inductance is an energy storage element, while magnetic bead is an energy conversion (consumption) device

2, inductance is mostly used in power supply filter circuit, magnetic bead is mostly used in signal circuit, EMC countermeasure

3, magnetic bead is mainly used to suppress electromagnetic radiation interference, while inductance is mainly used to suppress conductive interference. Both can be used to deal with EMC, EMI issues.

Two pathways of EMI, namely: radiation and conduction, different pathways adopt different suppression methods. The former uses magnetic beads, the latter uses inductors.

4, magnetic beads are used to absorb ultra-high frequency signals, such as some RF circuits, PLL, oscillation circuits, including ultra-high frequency memory circuits (DDR SDRAM,RAMBUS, etc.) all need to add magnetic beads to the power input part, while inductance is an energy storage element, used in LC oscillation circuits, medium and low frequency filter circuits, etc., and its application frequency range rarely exceeds 50MHZ.

5. Inductance is generally used for circuit matching and signal quality control. General ground connection and power connection.

Use magnetic beads where analog and digital are combined. Magnetic beads are also used for signal lines.

The size of the magnetic beads (to be exact, the characteristic curve of the magnetic beads) depends on the frequency of the interference wave that needs to be absorbed by the magnetic beads. Magnetic beads are high frequency resistance, low DC resistance, high frequency resistance. For example, 1000R @ 100Mhz means that there is a resistance of 1000 ohms for signals with a frequency of 100M. Because the unit of a magnetic bead is nominal according to the impedance it generates at a certain frequency, the unit of impedance is also ohms. The datasheet of magnetic beads is usually accompanied by a characteristic curve of frequency and impedance. Generally, 100MHz is taken as the standard, such as 2012B601, which means that the Impedance of magnetic beads is 600 ohms at 100MHz.

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