Monolithic Type Ferrite Bead


High predicted growth in demand for base stations, servers, and automotive electrical components means that there will be a need for ferrite bead for large current lines. Since Murata’s product lineup originally only offered capacities up to 6A, it has developed a monolithic type ferrite bead that is capable of accommodating up to 10A (BLE32P) as a pioneering product of ferrite bead for large current lines.

Making our life more comfortable and safer — to satisfy the needs, a transition to large current transmission has been in progress in infrastructural equipment and automotive electrical components. Present capacity enlargement in infrastructural equipment and automotive electrical components also demands that sub-components can comply with large current. To satisfy this requirement, the new monolithic ferrite bead has to be improved in terms of two properties.

One of them is to make sure components do not generate heat even if large current is applied. We were able to prevent the heat generation in conductors by reducing their DC resistance, thereby reducing the generation of heat in components. We circumvented the problem by making conductors (internal electrodes) made from low-resistance metal shorter, thicker, and wider, and thereby achieving the target DC resistance value of no more than 1mΩ.

Another challenge is to make sure users can remove noise sufficiently even if large current is applied. If you apply too much current on ferrites (magnetic bodies), they will reach magnetic saturation and the magnetic permeability will start to decrease. If the permeability decreases, the noise-suppressing effect of ferrite will be compromised, thereby causing malfunction or noise. To avoid such situations, we must reduce the magnetic saturation level of the ferrite. For that purpose, we created a gap (a nonmagnetic body) between conductors inside components, which considerably reduced the magnetic saturation level, allowing us to achieve noise suppression comparable to small current scenarios even when large current is applied.

By solving these two challenges, we have succeeded in creating ferrite bead for large current lines in the small size of 3.2 (L) x 2.5 (W) x 2.0 (t) mm. Because we expect the application in electronic devices in which large current flows, such as game devices, FPD TVs, and Blu-ray Disc recorders, we intend to develop various ferrite bead suitable to necessary electric current values, and contribute to more comfortable, safe, and enjoyable living. Since there is also demand for ferrite bead with capacity exceeding 10A, we intend to develop ferrite bead that can accommodate even larger current.

Construction Plan

External Appearance and Basic Characteristics

Size 3.2 (L) x 2.5 (W) x 2.0 (t) mm
Impedance 30Ω at 100MHz
DC resistance (RDC) 1.6mΩ (maximum value)
1.0mΩ (typical value)
Rated current 10A
Operating environment 125℃ including self-heat generation

* Rated current: temperature increase △T: no more than 40℃

The Impedance Characteristics When DC Current Is Applied

DC Resistance

BLE32PN300 BLM31PG330
DC resistance 1.6mΩ max 9.0mΩ max

Glossary

Ferrite bead: a type of noise filter. It is characterized by its capability to suppress noise in a broad range of frequencies.

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