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© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard

E5010_ESD-R-SR • 9/12/2018

Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com

EMI Core – ESD-R-SR Toroidal Cores for Round Cables for Low Frequency at 150 kHz (Bare, coated & with case)

Magnetic Permeability of Ferrite Material

In order to achieve most efficient noise reduction, it is important to select the material according to the target frequency

band. Depending on its magnetic permeability, a particular ferrite material will be effective in a certain frequency band.

A schematic representation of the relationship between the magnetic permeability of each material and the corresponding

effective band range is shown in Figure 1. Materials with higher magnetic permeability are effective in the lower frequency

range, while those with lower magnetic permeability are effective in the higher frequency range. Thus, Mn-Zn products are

mainly used for reducing conduction noise, while Ni-Zn products are commonly used for radiation noise countermeasures.

The effective frequency range varies depending on core shape, size and number of windings. This frequency dependence

of the magnetic permeability as shown in the figure serves for reference purposes only and it should be tested on the actual

device to determine its effectiveness.

S18H, S15H, 10H, 7H, 5H, 1400L and 700L are KEMET’s proprietary ferrite material names.

Other materials can also be available on request.

Figure 4 - Relationship between the magnetic permeability of each material and its effective frequency range

10 kHz

0

10,000

20,000

100 kHz

1 MHz

10 MHz

100 MHz

1 GHz

Effective Frequency Range

Ni-Zn Series

1400L

700L

S18H

S15H

10H

7H

5H

Mn-Zn Series

Lower magnetic permeability:

Higher noise suppression effect

in the higher frequency range

Higher magnetic permeability:

Higher noise suppression effect

in the lower frequency range