JPH0124975Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an ultra-small, high-performance noise filter for use in printed circuit boards.

As a chip-type ultra-small noise filter, a chip inductor in which a coil is formed inside an element body has been used.

However, since the insertion-loss curve is relatively gentle,
There is a problem that a sufficient noise removal effect cannot be obtained.

The purpose of this invention is to provide an extremely high-performance noise filter by adding the function of a capacitor to the function of an inductor, unlike the conventional chip inductor as described above.

That is, the structure of the noise filter of this invention is such that a plurality of magnetic sheets having internal electrodes reaching both ends and a plurality of magnetic sheets having internal electrodes reaching both sides are alternately laminated, and each electrode has an internal electrode. It is a laminate embedded in the laminate, and at both ends of the laminate there are external electrodes that are conductively connected to the internal electrodes that reach both ends, and in the center of the laminate that are conductively connected to the internal electrodes that reach both sides. The device is characterized in that it is provided with an external electrode.

Since the noise filter of this invention has the above configuration, for example, the signal line can be connected in series to the signal line by connecting the signal line to the external electrodes provided at both ends, and connecting the ground line to the external electrode leading to the internal electrodes that reach both sides. Since an inductance is inserted and a plurality of capacitors are formed between the inductance and the ground, the noise contained in the signal current is sequentially dropped to the ground line via each capacitor.

Therefore, the insertion loss curve becomes steeper, and the noise removal effect becomes significantly higher.

Hereinafter, one embodiment of this noise filter will be described based on the accompanying drawings.

In FIG. 1, numerals 1 and 2 are a plurality of sheets made of a magnetic material such as Ni-Zn ferrite. On the top surface of each of these sheets 1 and 2,
Internal electrodes 3 and 4 such as Ag/Pd are provided. Electrode 3 is linear and narrower than the width of sheet 1, reaching both ends of sheet 1, and electrode 4 is cross-shaped with its central part on both sides of sheet 2. has reached.

A plurality of sheets 1 and 2 as described above are laminated alternately, and sheets 5 made of a magnetic material having no electrodes are layered on top and bottom of this laminated body if necessary, and heated, compressed, and sintered to form an element body 6. , at both ends of this element 6
External electrodes 7 and 8 such as Ag/Pd are provided and both ends of each internal electrode 3 are connected to the external electrodes 7 and 8.

Further, an external electrode 9 made of the same material as the electrodes 7 and 8 is provided on the outer periphery of the element body 6 in the middle, and each internal electrode 4 is connected by this electrode.

The noise filter of this invention has the above structure, and as shown in the equivalent circuit of FIG.
Connect the signal line 10 to the external electrode 9 in the middle.
is connected to the ground line 11.

With such a circuit configuration, the inductance L of the signal line 10 increases and the capacitor C is inserted between the signal line and the ground line, so that the insertion loss becomes steeper and the noise removal performance is significantly improved.

In addition, since the external shape is similar to that of conventional chip parts for circuit boards, it is extremely easy to attach to a printed circuit board, and it is suitable for mass production and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of each sheet of the noise filter of this invention before molding, FIG. 2 is a perspective view of a completed product of the same, and FIG. 3 is an equivalent circuit of the same. 1, 2, 5... Sheet of magnetic material, 3, 4... Internal electrode, 7, 8, 9... External electrode.

Claims (1)

[Scope of utility model registration request] It is a laminated body in which a plurality of magnetic sheets having internal electrodes reaching both ends and a plurality of magnetic sheets having internal electrodes reaching both sides are alternately laminated, each electrode being buried inside. The laminate is characterized in that at both ends thereof, external electrodes are provided which are conductively connected to the internal electrodes reaching both ends, and at the center of the laminate, external electrodes are provided which are conductively connected to the internal electrodes that reach both ends. noise filter.