Common mode noise filter and mounting structure of common mode noise filter

Abstract

A substrate (90) constituting a common mode noise filter (10) has a first direction and a second direction that are parallel to the main surface and orthogonal to each other, and a first pad electrode (PDP1) and a second pad electrode (PDP2) are arranged side by side in the first direction. A first filter circuit electrode group is disposed between the first pad electrode (PDP1) and the second pad electrode (PDP2) in the first direction. A third pad electrode (PDP3) and a fourth pad electrode (PDP4) are arranged side by side in the first direction. A second filter circuit electrode group is disposed between the third pad electrode (PDP3) and the fourth pad electrode (PDP4) in the first direction. The first pad electrode (PDP1) and the third pad electrode (PDP3) are arranged side by side in the second direction. The second pad electrode (PDP2) and the fourth pad electrode (PDP4) are arranged side by side in the second direction. A ground pad electrode (PDG) is disposed between the first filter circuit electrode group and the second filter circuit electrode group in the second direction. A circuit board (50) is provided with a reference potential land electrode (PADG), a circuit board ground electrode (PT50G), and a ground via conductor (VIA50G). The reference potential land electrode (PADG) is formed on a surface (F50) of the circuit board (50), and the ground pad electrode (PDG) is mounted on the reference potential land electrode (PADG). The circuit board ground electrode (PT50G) is formed in the circuit board (50). The ground via conductor (VIA50G) has a columnar shape extending in the thickness direction of the circuit board (50), and connects the reference potential land electrode (PADG) and the circuit board ground electrode (PT50G). An inductor (300) is configured using the ground via conductor (VIA50G).

Description

Common mode noise filter, implementation structure of common mode noise filter

[0001] This invention relates to the structure of a common mode noise filter and the implementation structure of a common mode noise filter.

[0002] The common mode noise filter of Non-Patent Document 1 includes a first terminal, a second terminal, a third terminal, a fourth terminal, and a ground terminal.

[0003] The first terminal and the second terminal are arranged in a first direction and constitute the terminals of a first differential signal. The third terminal and the fourth terminal are arranged in the first direction and constitute the terminals of a second differential signal. The first terminal and the third terminal are arranged in a second direction orthogonal to the first direction. The second terminal and the fourth terminal are arranged in the second direction.

[0004] Between the first terminal and the second terminal, a first inductor and a second inductor that are magnetically coupled to each other are connected in series. A first capacitor is connected in parallel to the series circuit of the first inductor and the second inductor.

[0005] Between the third terminal and the fourth terminal, a third inductor and a fourth inductor that are magnetically coupled to each other are connected in series. A second capacitor is connected in parallel to the series circuit of the third inductor and the fourth inductor.

[0006] One terminal of a third capacitor is connected to the intermediate connection node between the first inductor and the second inductor. One end of a fourth capacitor is connected to the intermediate connection node between the third inductor and the fourth inductor. The other terminal of the third capacitor and the other terminal of the fourth capacitor are connected, and this connection node is connected to the ground terminal through a grounding inductor.

[0007] Such a common mode noise filter is configured using an electrode pattern formed on a semiconductor substrate.

[0008] An Ultra-Compact Common Mode Bandstop Filter With Modified-T Circuits in Integrated Passive Device (IPD) Process

[0009] However, in conventional common-mode noise electrode pattern configurations, the electrode patterns in the regions on the first and third terminal sides relative to the intermediate position in the first direction are not the same as the electrode patterns in the regions on the second and fourth terminal sides.

[0010] Therefore, the electrical characteristics of the region on the first and third terminals differ from those of the region on the second and fourth terminals. As a result, in conventional configurations, the filtering characteristics of the common-mode noise filter cannot be made sufficiently high.

[0011] Therefore, the object of the present invention is to provide a common-mode noise filter having excellent filtering characteristics and an implementation structure for this common-mode noise filter.

[0012] An implementation structure for a common-mode noise filter according to one embodiment of this invention comprises a substrate on which a common-mode noise filter using a first differential signal and a second differential signal is formed, and a circuit board on which the substrate is mounted.

[0013] The common-mode noise filter comprises a first pad electrode, a second pad electrode, a third pad electrode, a fourth pad electrode, a first filter circuit electrode group, a second filter circuit electrode group, a ground pad electrode, and an inductor element.

[0014] The first pad electrode is formed to be exposed on the surface of the substrate and constitutes one terminal of the first differential signal. The second pad electrode is formed to be exposed on the surface of the substrate and constitutes the other terminal of the first differential signal. The third pad electrode is formed to be exposed on the surface of the substrate and constitutes one terminal of the second differential signal. The fourth pad electrode is formed to be exposed on the surface of the substrate and constitutes the other terminal of the second differential signal.

[0015] The first filter circuit electrode group is formed on the substrate and connected to the first pad electrode and the second pad electrode, constituting the first filter of the common-mode noise filter. The second filter circuit electrode group is formed on the substrate and connected to the third pad electrode and the fourth pad electrode, constituting the second filter of the common-mode noise filter. The ground pad electrode connects the first filter circuit electrode group and the second filter circuit electrode group to a reference potential. The inductor element is connected in series with the ground pad electrode.

[0016] The substrate has a first direction and a second direction that are parallel to the main surface and orthogonal to each other, and the first pad electrode and the second pad electrode are arranged side by side in the first direction. The first filter circuit electrode group is arranged between the first pad electrode and the second pad electrode in the first direction. The third pad electrode and the fourth pad electrode are arranged side by side in the first direction. The second filter circuit electrode group is arranged between the third pad electrode and the fourth pad electrode in the first direction. The first pad electrode and the third pad electrode are arranged side by side in the second direction. The second pad electrode and the fourth pad electrode are arranged side by side in the second direction. The ground pad electrode is arranged between the first filter circuit electrode group and the second filter circuit electrode group in the second direction.

[0017] The circuit board comprises a reference potential land electrode, a circuit board ground electrode, and a ground via conductor. The reference potential land electrode is formed on the surface of the circuit board, and a ground pad electrode is mounted on it. The circuit board ground electrode is formed within the circuit board. The ground via conductor is columnar, extending in the thickness direction of the circuit board, and connects the reference potential land electrode and the circuit board ground electrode.

[0018] The inductor element is constructed using a via conductor for ground.

[0019] In this configuration, in a plan view, the common-mode noise filter has an electrode pattern symmetrical with respect to a line passing through the center of each of the first and second directions. Furthermore, the inductor element is located at the center of both the first and second directions in a plan view.

[0020] As a result, the common-mode noise filter has the same electrical characteristics in the region on the first and third pad electrodes as it does in the region on the second and fourth pad electrodes. Therefore, excellent filter characteristics can be achieved.

[0021] Furthermore, the inductor element connected to the reference potential is not placed on the substrate forming the common-mode noise filter, but rather on the circuit board on which the substrate is mounted. This makes it easier to set the inductance (impedance) of the inductor element to the desired value without changing the shape of the substrate.

[0022] A common-mode noise filter according to one embodiment of this invention comprises a first pad electrode, a second pad electrode, a third pad electrode, a fourth pad electrode, a first filter circuit electrode group, a second filter circuit electrode group, a ground pad electrode, and an inductor element.

[0023] The first pad electrode is formed to be exposed on the surface of the substrate and constitutes one terminal of the first differential signal. The second pad electrode is formed to be exposed on the surface of the substrate and constitutes the other terminal of the first differential signal. The third pad electrode is formed to be exposed on the surface of the substrate and constitutes one terminal of the second differential signal. The fourth pad electrode is formed to be exposed on the surface of the substrate and constitutes the other terminal of the second differential signal. The first filter circuit electrode group is formed on the substrate and connected to the first and second pad electrodes, constituting the first filter of the common-mode noise filter. The second filter circuit electrode group is formed on the substrate and connected to the third and fourth pad electrodes, constituting the second filter of the common-mode noise filter. The ground pad electrode connects the first filter circuit electrode group and the second filter circuit electrode group to a reference potential. The inductor element is connected in series with the reference potential connection electrode.

[0024] The substrate has a first direction and a second direction that are parallel to the main surface and orthogonal to each other. The first pad electrode and the second pad electrode are arranged side by side in the first direction. The first filter circuit electrode group is arranged between the first pad electrode and the second pad electrode in the first direction. The third pad electrode and the fourth pad electrode are arranged side by side in the first direction. The second filter circuit electrode group is arranged between the third pad electrode and the fourth pad electrode in the first direction. The first pad electrode and the third pad electrode are arranged side by side in the second direction. The second pad electrode and the fourth pad electrode are arranged side by side in the second direction. The ground pad electrode and the inductor element are positioned midway between the first filter circuit electrode group and the second filter circuit electrode group in the second direction.

[0025] In this configuration, in a plan view, the common-mode noise filter has an electrode pattern symmetrical with respect to a line passing through the center of each of the first and second directions. Furthermore, the inductor element is located at the center of both the first and second directions in a plan view.

[0026] As a result, the common-mode noise filter has the same electrical characteristics in the region on the first and third pad electrodes as it does in the region on the second and fourth pad electrodes. Therefore, excellent filter characteristics can be achieved.

[0027] This configuration enables the achievement of excellent filtering characteristics in a configuration that includes a common-mode noise filter.

[0028] Figure 1 is a circuit diagram of a common-mode noise filter according to an embodiment of the present invention. Figure 2 is a plan view of the substrate constituting the common-mode noise filter according to an embodiment of the present invention. Figures 3(A) and 3(B) are cross-sectional views of the substrate constituting the common-mode noise filter according to an embodiment of the present invention. Figures 4(A) and 4(B) show an example of the mounting structure of the common-mode noise filter according to an embodiment of the present invention onto a circuit board. Figure 5 is a schematic diagram showing the configuration of an n-stage common-mode noise filter.

[0029] A common-mode noise filter and an implementation structure of the common-mode noise filter according to an embodiment of the present invention will be described with reference to the figures.

[0030] (Circuit Configuration) Figure 1 is a circuit diagram of a common-mode noise filter according to an embodiment of the present invention. As shown in Figure 1, the common-mode noise filter 10 comprises a first common-mode noise filter 21, a second common-mode noise filter 22, and a third common-mode noise filter 23. The common-mode noise filter 10 comprises a first terminal P1, a second terminal P2, a third terminal P3, and a fourth terminal P4.

[0031] The first terminal P1 and the second terminal P2 are terminals for the first differential signal. The third terminal P3 and the fourth terminal P4 are terminals for the second differential signal (the signal that pairs with the first differential signal). The first and second differential signals are high-frequency signals with the same frequency but different phases.

[0032] The first terminal P1 and the third terminal P3 constitute one end of the pair of differential signals in the common-mode noise filter 10. The second terminal P2 and the fourth terminal P4 constitute the other end of the pair of differential signals in the common-mode noise filter 10.

[0033] The first terminal P1 and the third terminal P3 are connected to the first common-mode noise filter 21. The first common-mode noise filter 21 is connected to the second common-mode noise filter 22. The second common-mode noise filter 22 is connected to the third common-mode noise filter 23. The third common-mode noise filter 23 is connected to the second terminal P2 and the fourth terminal P4.

[0034] Furthermore, the first common-mode noise filter 21, the second common-mode noise filter 22, and the third common-mode noise filter 23 are connected to a reference potential through the inductor 300. The inductor 300 corresponds to the "inductor element" of the present invention.

[0035] Thus, the first common-mode noise filter 21, the second common-mode noise filter 22, and the third common-mode noise filter 23 are connected in series between the terminal pair of the first terminal P1 and the third terminal P3 and the terminal pair of the second terminal P2 and the fourth terminal P4. As a result, the common-mode noise filter 10 constitutes a three-stage common-mode noise filter.

[0036] (Circuit of the first common-mode noise filter 21) The first common-mode noise filter 21 comprises a first T-type filter circuit 21T1 and a second T-type filter circuit 21T2.

[0037] The first T-type filter circuit 21T1 includes an inductor 311, an inductor 312, a capacitor 313, and a shunt capacitor 317. Inductors 311 and 312 are connected in series. Inductors 311 and 312 are magnetically coupled in the forward direction.

[0038] The series circuit of inductors 311 and 312 is connected in parallel to the capacitor 313. One terminal of the shunt capacitor 317 is connected to the intermediate node where inductors 311 and 312 are connected. The terminal of inductor 311 opposite to the terminal connected to inductor 312 is connected to the first terminal P1.

[0039] The second T-type filter circuit 21T2 includes inductors 314 and 315, a capacitor 316, and a shunt capacitor 318. Inductors 314 and 315 are connected in series. Inductors 314 and 315 are magnetically coupled in the forward direction.

[0040] The series circuit of inductors 314 and 315 is connected in parallel to the capacitor 316. One terminal of the shunt capacitor 318 is connected to the intermediate node where inductors 314 and 315 are connected. The terminal of inductor 314 opposite to the terminal connected to inductor 315 is connected to the third terminal P3.

[0041] The other terminal of the shunt capacitor 317 and the other terminal of the shunt capacitor 318 are connected, and this connection point is connected to the reference potential through the inductor 300.

[0042] The inductance of the inductor 311, the inductance of the inductor 312, the inductance of the inductor 314, and the inductance of the inductor 315 are the same.

[0043] The capacitance of the capacitor 313 and the capacitance of the capacitor 316 are the same. The capacitance of the shunt capacitor 317 and the capacitance of the shunt capacitor 318 are the same.

[0044] (Circuit of the second common-mode noise filter 22) The second common-mode noise filter 22 includes a third T-type filter circuit 22T1 and a fourth T-type filter circuit 22T2.

[0045] The third T-type filter circuit 22T1 includes an inductor 321, an inductor 322, a capacitor 323, and a shunt capacitor 327. The inductor 321 and the inductor 322 are connected in series. The inductor 321 and the inductor 322 are magnetically coupled in the forward direction.

[0046] The series circuit of the inductor 321 and the inductor 322 and the capacitor 323 are connected in parallel. One terminal of the shunt capacitor 327 is connected to the intermediate node where the inductor 321 and the inductor 322 are connected.The terminal of the inductor 321 on the side opposite to the connection end with the inductor 322 is connected to the inductor 312 of the first T-type filter circuit 21T1

[0047] The fourth T-type filter circuit 22T2 includes an inductor 324, an inductor 325, a capacitor 326, and a shunt capacitor 328. The inductor 324 and the inductor 325 are connected in series. The inductor 324 and the inductor 325 are magnetically coupled in the forward direction.

[0048] The series circuit of inductor 324 and inductor 325 and capacitor 326 are connected in parallel. One terminal of shunt capacitor 328 is connected to the intermediate node where inductor 324 and inductor 325 are connected. The terminal of inductor 324 opposite to the connection end with inductor 325 is connected to inductor 315 of the second T-type filter circuit 21T2.

[0049] The other terminal of shunt capacitor 327 and the other terminal of shunt capacitor 328 are connected, and this connection point is connected to the reference potential through inductor 300.

[0050] The inductance of inductor 321, the inductances of inductor 322, inductor 324, and inductor 325 are the same. The inductances of inductors 321, 322, 324, 325 are the same as the inductance of inductor 311, the inductance of inductor 312, the inductance of inductor 314, and the inductance of inductor 315.

[0051] The capacitance of capacitor 323 and the capacitance of capacitor 326 are the same. The capacitances of capacitors 323, 326 are the same as the capacitance of capacitor 313 and the capacitance of capacitor 316.

[0052] The capacitance of shunt capacitor 327 and the capacitance of shunt capacitor 328 are the same. The capacitances of shunt capacitors 327, 328 are the same as the capacitance of shunt capacitor 317 and the capacitance of shunt capacitor 318.

[0053] (Circuit of the third common-mode noise filter 23) The third common-mode noise filter 23 includes a fifth T-type filter circuit 23T1 and a sixth T-type filter circuit 23T2.

[0054] The fifth T-type filter circuit 23T1 includes an inductor 331, an inductor 332, a capacitor 333, and a shunt capacitor 337. Inductors 331 and 332 are connected in series. Inductors 331 and 332 are magnetically coupled in the forward direction.

[0055] The series circuit of inductors 331 and 332 is connected in parallel to the capacitor 333. One terminal of the shunt capacitor 337 is connected to the intermediate node where inductors 331 and 332 are connected. The terminal of inductor 331 opposite to the terminal connected to inductor 332 is connected to inductor 322 of the third T-type filter circuit 22T1. The terminal of inductor 332 opposite to the terminal connected to inductor 331 is connected to the second terminal P2.

[0056] The sixth T-type filter circuit 23T2 comprises inductors 334 and 335, a capacitor 336, and a shunt capacitor 338. Inductors 334 and 335 are connected in series. Inductors 334 and 335 are magnetically coupled in the forward direction.

[0057] The series circuit of inductors 334 and 335 is connected in parallel to the capacitor 336. One terminal of the shunt capacitor 338 is connected to the intermediate node where inductors 334 and 335 are connected. The terminal of inductor 334 opposite to the terminal connected to inductor 335 is connected to inductor 325 of the fourth T-type filter circuit 22T2. The terminal of inductor 335 opposite to the terminal connected to inductor 334 is connected to the fourth terminal P4.

[0058] The other terminal of shunt capacitor 337 and the other terminal of shunt capacitor 338 are connected, and this connection point is connected to a reference potential through inductor 300.

[0059] The inductances of inductor 331, inductor 332, inductor 334, and inductor 335 are the same. The inductances of inductors 331, 332, 334, and 335 are the same as the inductances of inductor 311, inductor 312, inductor 314, and inductor 315.

[0060] The capacitance of capacitor 333 and the capacitance of capacitor 336 are the same. The capacitances of capacitors 333 and 336 are the same as the capacitances of capacitor 313 and capacitor 316.

[0061] The capacitance of shunt capacitor 337 and the capacitance of shunt capacitor 338 are the same. The capacitances of shunt capacitors 337 and 338 are the same as the capacitances of shunt capacitor 317 and shunt capacitor 318.

[0062] With this configuration, the common-mode noise filter 10 receives the first differential signal of the pair of differential signals from the first terminal P1, transmits it through the first T-type filter circuit 21T1, the third T-type filter circuit 22T1, and the fifth T-type filter circuit 23T1, and outputs it from the second terminal P2. Furthermore, the common-mode noise filter 10 receives the second differential signal of the pair of differential signals from the third terminal P3, transmits it through the second T-type filter circuit 21T2, the fourth T-type filter circuit 22T2, and the sixth T-type filter circuit 23T2, and outputs it from the fourth terminal P4. Thus, the common-mode noise filter 10 suppresses common-mode noise superimposed on the pair of differential signals with the above circuit configuration.

[0063] Alternatively, the common-mode noise filter 10 receives the first differential signal of the pair of differential signals from the second terminal P2, transmits it through the fifth T-type filter circuit 23T1, the third T-type filter circuit 22T1, and the first T-type filter circuit 21T1, and outputs it from the first terminal P1. Furthermore, the common-mode noise filter 10 receives the second differential signal of the pair of differential signals from the fourth terminal P4, transmits it through the sixth T-type filter circuit 23T2, the fourth T-type filter circuit 22T2, and the second T-type filter circuit 21T2, and outputs it from the third terminal P3. With the above circuit configuration, the common-mode noise filter 10 suppresses common-mode noise superimposed on the pair of differential signals.

[0064] Furthermore, the common-mode noise filter 10 has two circuit configurations: a first configuration in which the first terminal P1 and the third terminal P3 are input terminals and the second terminal P2 and the fourth terminal P4 are output terminals, and a second configuration in which the second terminal P2 and the fourth terminal P4 are input terminals and the first terminal P1 and the third terminal P3 are output terminals. In both configurations, the electrical circuit configuration for the flow of high-frequency signals is the same. As a result, the common-mode noise filter 10 can achieve excellent filtering characteristics.

[0065] (Structure of Common Mode Noise Filter 10) Figure 2 is a plan view of the substrate constituting the common mode noise filter according to an embodiment of the present invention. Figures 3(A) and 3(B) are cross-sectional views of the substrate constituting the common mode noise filter according to an embodiment of the present invention. Figure 3(A) is a cross-sectional view based on the cross-sectional line LINECS1 shown in Figure 2, and Figure 3(B) is a cross-sectional view based on the cross-sectional line LINECS2 shown in Figure 2.

[0066] As shown in Figures 2, 3(A), and 3(B), the common-mode noise filter 10 is formed by a substrate 90 made of a semiconductor substrate. The substrate 90 comprises a base material 900 and a plurality of insulating layers 91, 92, 93, and 94. The base material 900 is made of, for example, an undoped semiconductor. Note that the base material 900 is not limited to a semiconductor substrate, but may be an insulating material such as a glass substrate. The insulating layer 91 is formed on the surface of the base material 900 and is made of a highly insulating material such as SiN. The insulating layers 92, 93, and 94 are made of a material having a predetermined dielectric constant. The insulating layers 92, 93, and 94 are formed on the surface of the insulating layer 91 in the order of insulating layer 92, insulating layer 93, and insulating layer 94.

[0067] The interface (contact surface) between the insulating layer 91 and the insulating layer 92 is used as the third conductive layer CLY3. The interface between the insulating layer 92 and the insulating layer 93 is used as the second conductive layer CLY2. The interface between the insulating layer 91 and the insulating layer 92 is used as the first conductive layer CLY1.

[0068] The common-mode noise filter 10 includes a first pad electrode PDP1, a second pad electrode PDP2, a third pad electrode PDP3, a fourth pad electrode PDP4, and a ground pad electrode PDG.

[0069] The first pad electrode PDP1 constitutes the first terminal P1. The second pad electrode PDP2 constitutes the second terminal P2. The third pad electrode PDP3 constitutes the third terminal P3. The fourth pad electrode PDP4 constitutes the fourth terminal P4.

[0070] The ground pad electrode PDG is an electrode for connecting to a reference potential, and in terms of the circuit, it corresponds to the position of the connection node between the first common-mode noise filter 21, the second common-mode noise filter 22, and the third common-mode noise filter 23 and the inductor 300.

[0071] The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG have an area that allows for solder bonding when mounting the common-mode noise filter 10 (substrate 90) onto the circuit board 50 (see Figure 4). It is preferable that the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4 have substantially the same shape when viewed in plan (viewed in the direction of stacking of the multiple insulating layers of the substrate 90).

[0072] The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG are formed in the electrode pattern of the first conductive layer CLY1 and are exposed to the outside over a predetermined area on the surface F901 of the substrate 90 by the opening OPG formed in the insulating layer 91.

[0073] The first pad electrode PDP1 and the second pad electrode PDP2 are positioned at a predetermined distance from each other along the first direction (the Y-axis direction in Figure 2) of the substrate 90. The first pad electrode PDP1 and the second pad electrode PDP2 are positioned on a line parallel to the Y-axis. In other words, the first pad electrode PDP1 and the second pad electrode PDP2 are positioned at the same location in the X-axis direction.

[0074] The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned at a predetermined distance from each other along the first direction (the Y-axis direction in Figure 2) of the substrate 90. The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned on a line parallel to the Y-axis. In other words, the third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned at the same location in the X-axis direction.

[0075] The first pad electrode PDP1 and the third pad electrode PDP3 are positioned at a predetermined distance from each other along the second direction (the X-axis direction in Figure 2) of the substrate 90. The first pad electrode PDP1 and the third pad electrode PDP3 are positioned on a line parallel to the X-axis. In other words, the first pad electrode PDP1 and the third pad electrode PDP3 are positioned at the same location in the Y-axis direction.

[0076] The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned at a predetermined distance from each other along the second direction (the X-axis direction in Figure 2) of the substrate 90. The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned on a line parallel to the X-axis. In other words, the second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned at the same location in the Y-axis direction.

[0077] The ground pad electrode PDG is positioned so as to include the center point of a rectangle formed by the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4 as its four corners. In this case, it is preferable that the center point of the ground pad electrode PDG coincides with the center point of the rectangle.

[0078] As a result, the first pad electrode PDP1 and the second pad electrode PDP2 are positioned symmetrically with respect to the X-axis reference line AxeX, which passes through the center point of the ground pad electrode PDG. The third pad electrode PDP3 and the fourth pad electrode PDP4 are positioned symmetrically with respect to the X-axis reference line AxeX.

[0079] The first pad electrode PDP1 and the third pad electrode PDP3 are positioned symmetrically with respect to the Y-axis reference line AxeY, which passes through the center point of the ground pad electrode PDG. The second pad electrode PDP2 and the fourth pad electrode PDP4 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0080] The common-mode noise filter 10 comprises a plurality of capacitor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, and Pt336. Each of the plurality of capacitor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, and Pt336 is configured such that a first flat plate electrode formed in the first conductive layer CLY1 and a second flat plate electrode formed in the second conductive layer CLY2 face each other with an insulating layer 91 in between.

[0081] As a result, each of the multiple capacitor electrodes Pt313, Pt316, Pt323, Pt326, Pt333, and Pt336 constitutes, in a circuit-like manner, multiple capacitors 313, 316, 323, 326, 333, and 336, respectively.

[0082] Multiple capacitor electrodes Pt313, Pt323, and Pt333 are arranged in the Y-axis direction between the first pad electrode PDP1 and the second pad electrode PDP2. The multiple capacitor electrodes Pt313, Pt323, and Pt333 are arranged in the order of capacitor electrode Pt313, capacitor electrode Pt323, and capacitor electrode Pt333, from the first pad electrode PDP1 side toward the second pad electrode PDP2 side.

[0083] Capacitor electrodes Pt313, Pt323, and Pt333 are arranged in an array along the Y-axis. Preferably, this arrangement is equally spaced along the Y-axis. Furthermore, the center of this arrangement in the Y-axis direction is positioned to coincide with, or approximately coincide with, the X-axis reference line AxeX. Capacitor electrodes Pt313, Pt323, and Pt333 are positioned in a location that coincides with the position of the first pad electrode PDP1 and the second pad electrode PDP2 in the X-axis direction.

[0084] Multiple capacitor electrodes Pt316, Pt326, and Pt336 are arranged in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4. The multiple capacitor electrodes Pt316, Pt326, and Pt336 are arranged in the order of capacitor electrode Pt316, capacitor electrode Pt326, and capacitor electrode Pt336, from the third pad electrode PDP3 side to the fourth pad electrode PDP4 side.

[0085] Capacitor electrodes Pt316, Pt326, and Pt336 are arranged in an array along the Y-axis. Preferably, this array is equally spaced along the Y-axis. Furthermore, the center of this array in the Y-axis direction is positioned to coincide with, or approximately coincide with, the X-axis reference line AxeX. Capacitor electrodes Pt316, Pt326, and Pt336 are positioned in a location that coincides with the position of the third pad electrode PDP3 and the fourth pad electrode PDP4 in the X-axis direction.

[0086] Capacitor electrodes Pt313 and Pt316 are positioned symmetrically with respect to the Y-axis reference line AxeY. Capacitor electrodes Pt323 and Pt326 are positioned symmetrically with respect to the Y-axis reference line AxeY. Capacitor electrodes Pt333 and Pt336 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0087] The common-mode noise filter 10 comprises a plurality of inductor electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, and Pt335. Each of the plurality of inductor electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, and Pt335 constitutes each of the plurality of inductors 311, 312, 314, 315, 321, 322, 324, 325, 331, 332, 334, and 335, respectively.

[0088] Multiple inductor electrodes Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, and Pt335 are each formed as linear electrodes and are formed in the first conductive layer CLY1 and the second conductive layer CLY2.

[0089] Multiple inductor electrodes Pt311, Pt312, Pt321, Pt322, Pt331, and Pt332 are arranged in the Y-axis direction between the first pad electrode PDP1 and the second pad electrode PDP2. The multiple inductor electrodes Pt311, Pt312, Pt321, Pt322, Pt331, and Pt332 are formed in the order of inductor electrode Pt311, inductor electrode Pt312, inductor electrode Pt321, inductor electrode Pt322, inductor electrode Pt331, and inductor electrode Pt332, moving from the first pad electrode PDP1 side toward the second pad electrode PDP2 side.

[0090] The centers of the Y-axis direction of the array of inductor electrodes Pt311, Pt312, Pt321, Pt322, Pt331, and Pt332 are positioned to coincide with, or nearly coincide with, the X-axis reference line AxeX.

[0091] Multiple inductor electrodes Pt314, Pt315, Pt324, Pt325, Pt334, and Pt335 are arranged in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4. The multiple inductor electrodes Pt314, Pt315, Pt324, Pt325, Pt334, and Pt335 are formed in the order of inductor electrode Pt314, inductor electrode Pt315, inductor electrode Pt324, inductor electrode Pt325, inductor electrode Pt334, and inductor electrode Pt335, moving from the third pad electrode PDP3 side towards the fourth pad electrode PDP4 side.

[0092] The centers of the Y-axis direction of the array of inductor electrodes Pt314, Pt315, Pt324, Pt325, Pt334, and Pt335 are positioned to coincide with, or nearly coincide with, the X-axis reference line AxeX.

[0093] Inductor electrodes Pt311 and Pt314 are positioned symmetrically with respect to the Y-axis reference line AxeY. Inductor electrodes Pt312 and Pt315 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0094] Inductor electrodes Pt321 and Pt324 are positioned symmetrically with respect to the Y-axis reference line AxeY. Inductor electrodes Pt322 and Pt325 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0095] Inductor electrodes Pt331 and Pt334 are positioned symmetrically with respect to the Y-axis reference line AxeY. Inductor electrodes Pt332 and Pt335 are positioned symmetrically with respect to the Y-axis reference line AxeY.

[0096] The common-mode noise filter 10 comprises filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, Pt338 of a plurality of shunt capacitors, and reference potential connection electrodes PtCG1, PtCG2 of the shunt capacitors.

[0097] Multiple filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, and Pt338 are each rectangular in shape with a predetermined area and are formed in the second conductive layer CLY2.

[0098] The reference potential connection electrode PtCG1 is formed in the first conductive layer CLY1. The reference potential connection electrode PtCG2 is formed in the third conductive layer CLY3.

[0099] Reference potential connection electrodes PtCG1 and PtCG2 overlap with multiple filter-side electrodes Pt317, Pt318, Pt327, Pt328, Pt337, and Pt338 in a plan view.

[0100] The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt317 overlap and face each other constitutes a shunt capacitor 317. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt318 overlap and face each other constitutes a shunt capacitor 318.

[0101] The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt327 overlap and face each other constitutes a shunt capacitor 327. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt328 overlap and face each other constitutes a shunt capacitor 328.

[0102] The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt337 overlap and face each other constitutes a shunt capacitor 337. The portion where the reference potential connection electrodes PtCG1 and PtCG2 and the filter-side electrode Pt338 overlap and face each other constitutes a shunt capacitor 338.

[0103] Multiple filter-side electrodes Pt317, Pt327, and Pt337 are arranged in the Y-axis direction between the first pad electrode PDP1 and the second pad electrode PDP2. In the Y-axis direction, the multiple filter-side electrodes Pt317, Pt327, and Pt337 are arranged in the order of filter-side electrode Pt317, filter-side electrode Pt327, and filter-side electrode Pt337, from the first pad electrode PDP1 side to the second pad electrode PDP2 side.

[0104] As a result, the multiple shunt capacitors 317, 327, and 337 are positioned between the first pad electrode PDP1 and the second pad electrode PDP2 in the Y-axis direction.

[0105] The Y-axis centers of the array of filter-side electrodes Pt317, Pt327, and Pt337 are positioned so as to coincide with, or nearly coincide with, the X-axis reference line AxeX.

[0106] The filter-side electrode Pt317 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt311, Pt312 and capacitor electrode Pt313 in the X-axis direction. The filter-side electrode Pt327 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt321, Pt322 and capacitor electrode Pt323 in the X-axis direction. The filter-side electrode Pt337 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt331, Pt332 and capacitor electrode Pt333 in the X-axis direction.

[0107] Multiple filter-side electrodes Pt318, Pt328, and Pt338 are arranged in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4. In the Y-axis direction, the multiple filter-side electrodes Pt318, Pt328, and Pt338 are arranged in the order of filter-side electrode Pt318, filter-side electrode Pt328, and filter-side electrode Pt338, from the third pad electrode PDP3 side to the fourth pad electrode PDP4 side.

[0108] As a result, the multiple shunt capacitors 318, 328, and 338 are positioned in the Y-axis direction between the third pad electrode PDP3 and the fourth pad electrode PDP4.

[0109] The Y-axis centers of the array of filter-side electrodes Pt318, Pt328, and Pt338 are positioned to coincide with, or nearly coincide with, the X-axis reference line AxeX.

[0110] The filter-side electrode Pt318 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt314, Pt315 and capacitor electrode Pt316 in the X-axis direction. The filter-side electrode Pt328 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt324, Pt325 and capacitor electrode Pt326 in the X-axis direction. The filter-side electrode Pt338 is positioned on the ground pad electrode PDG side of the inductor electrodes Pt334, Pt335 and capacitor electrode Pt336 in the X-axis direction.

[0111] The filter circuit electrode group of the first T-type filter circuit 21T1 is formed by multiple inductor electrodes Pt311, Pt312, multiple capacitor electrodes Pt313, multiple filter-side electrodes Pt317, and the portions of the reference potential connection electrodes PtCG1, PtCG2 that overlap with the multiple filter-side electrodes Pt317.

[0112] The filter circuit electrode group of the third T-type filter circuit 22T1 is formed by multiple inductor electrodes Pt321 and Pt322, multiple capacitor electrodes Pt323, multiple filter-side electrodes Pt327, and the portions of the reference potential connection electrodes PtCG1 and PtCG2 that overlap with the multiple filter-side electrodes Pt327.

[0113] The filter circuit electrode group of the fifth T-type filter circuit 23T1 is formed by multiple inductor electrodes Pt331 and Pt332, multiple capacitor electrodes Pt333, multiple filter-side electrodes Pt337, and the portions of the reference potential connection electrodes PtCG1 and PtCG2 that overlap with the multiple filter-side electrodes Pt337.

[0114] The filter circuit electrode group of the first T-type filter circuit 21T1, the filter circuit electrode group of the third T-type filter circuit 22T1, and the filter circuit electrode group of the fifth T-type filter circuit 23T1 each correspond to the "first filter circuit electrode group" of the present invention.

[0115] The filter circuit electrode group of the second T-type filter circuit 21T2 is formed by multiple inductor electrodes Pt314, Pt315, multiple capacitor electrodes Pt316, multiple filter-side electrodes Pt318, and the portions of the reference potential connection electrodes PtCG1, PtCG2 that overlap with the multiple filter-side electrodes Pt318.

[0116] The filter circuit electrode group of the fourth T-type filter circuit 22T2 is formed by multiple inductor electrodes Pt324, Pt325, multiple capacitor electrodes Pt326, multiple filter-side electrodes Pt328, and the portions of the reference potential connection electrodes PtCG1, PtCG2 that overlap with the multiple filter-side electrodes Pt328.

[0117] The filter circuit electrode group of the sixth T-type filter circuit 23T2 is formed by multiple inductor electrodes Pt334, Pt335, multiple capacitor electrodes Pt336, multiple filter-side electrodes Pt338, and the portions of the reference potential connection electrodes PtCG1, PtCG2 that overlap with the multiple filter-side electrodes Pt338.

[0118] The filter circuit electrode group of the second T-type filter circuit 21T2, the filter circuit electrode group of the fourth T-type filter circuit 22T2, and the filter circuit electrode group of the sixth T-type filter circuit 23T2 each correspond to the "second filter circuit electrode group" of the present invention.

[0119] In terms of the relationship between multiple filter circuit electrode groups and the X-axis reference line AxeX and the Y-axis reference line AxeY, the filter circuit electrode group of the first T-type filter circuit 21T1 and the filter circuit electrode group of the fifth T-type filter circuit 23T1 are positioned symmetrically with respect to the X-axis reference line AxeX. The filter circuit electrode group of the third T-type filter circuit 22T1 is positioned to coincide with the X-axis reference line AxeX.

[0120] The filter circuit electrode group of the second T-type filter circuit 21T2 and the filter circuit electrode group of the sixth T-type filter circuit 23T2 are positioned symmetrically with respect to the X-axis reference line AxeX. The filter circuit electrode group of the fourth T-type filter circuit 22T2 is positioned to coincide with the X-axis reference line AxeX.

[0121] Multiple first filter circuit electrode groups (filter circuit electrode group of the first T-type filter circuit 21T1, filter circuit electrode group of the third T-type filter circuit 22T1, and filter circuit electrode group of the fifth T-type filter circuit 23T1) and multiple second filter circuit electrode groups (filter circuit electrode group of the second T-type filter circuit 21T2, filter circuit electrode group of the fourth T-type filter circuit 22T2, and filter circuit electrode group of the sixth T-type filter circuit 23T2) are arranged symmetrically with respect to the Y-axis reference line AxeY.

[0122] More specifically, the filter circuit electrode group of the first T-type filter circuit 21T1 and the filter circuit electrode group of the second T-type filter circuit 21T2 are arranged symmetrically with respect to the Y-axis reference line AxeY. The filter circuit electrode group of the third T-type filter circuit 22T1 and the filter circuit electrode group of the fourth T-type filter circuit 22T2 are arranged symmetrically with respect to the Y-axis reference line AxeY. The filter circuit electrode group of the fifth T-type filter circuit 23T1 and the filter circuit electrode group of the sixth T-type filter circuit 23T2 are arranged symmetrically with respect to the Y-axis reference line AxeY.

[0123] The reference potential connection electrodes PtCG1 and PtCG2 are positioned to overlap the X-axis reference line AxeX and the Y-axis reference line AxeY. The reference potential connection electrodes PtCG1 and PtCG2 are positioned to include the center of the electrode pattern group of the common-mode noise filter 10 where the X-axis reference line AxeX and the Y-axis reference line AxeY intersect.

[0124] The reference potential connection electrodes PtCG1 and PtCG2 are connected via a via conductor VIA1 formed in the insulating layer 93, a wiring electrode Ptcnt formed in the second conductive layer CLY2, and a via conductor VIA2 formed in the insulating layer 92 (see Figure 4(B)). The via conductor VIA1, the wiring electrode Ptcnt, and the via conductor VIA2 are arranged on the Y-axis reference line AxeY and are arranged symmetrically with respect to the X-axis reference line AxeX.

[0125] The ground pad electrode PDG is formed on the reference potential connection electrode PtCG1. In this case, the ground pad electrode PDG is formed to include the center of the reference potential connection electrode PtCG1 in a plan view. In other words, the ground pad electrode PDG is formed to include the center of the electrode pattern group of the common-mode noise filter 10 where the X-axis reference line AxeX and the Y-axis reference line AxeY intersect.

[0126] With this configuration, the ground pad electrode PDG is positioned in the middle of the arrangement pattern of the multiple first filter circuit electrode groups and the multiple second filter circuit electrode groups in a plan view. More specifically, the ground pad electrode PDG is positioned in the middle of the central first filter circuit electrode group (the filter circuit electrode group of the third T-type filter circuit 22T1) in the multiple first filter circuit electrode groups and the central second filter circuit electrode group (the filter circuit electrode group of the fourth T-type filter circuit 22T2) in the multiple second filter circuit electrode groups.

[0127] As a result, the ground pad electrode PDG is positioned at a structurally and electrically equidistant location with respect to multiple first filter circuit electrode groups and multiple second filter circuit electrode groups. More specifically, the ground pad electrode PDG is positioned at a structurally and electrically equidistant location with respect to the filter circuit electrode group of the first T-type filter circuit 21T1 and the filter circuit electrode group of the second T-type filter circuit 21T2. The ground pad electrode PDG is positioned at a structurally and electrically equidistant location with respect to the filter circuit electrode group of the third T-type filter circuit 22T1 and the filter circuit electrode group of the fourth T-type filter circuit 22T2. The ground pad electrode PDG is positioned at a structurally and electrically equidistant location with respect to the filter circuit electrode group of the fifth T-type filter circuit 23T1 and the filter circuit electrode group of the sixth T-type filter circuit 23T2.

[0128] Furthermore, the ground pad electrode PDG is positioned in the center of the arrangement pattern of the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4 in a plan view. As a result, the ground pad electrode PDG is positioned at an equidistant location, both structurally and electrically, with respect to the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4.

[0129] (Implementation structure of common-mode noise filter 10) Figures 4(A) and 4(B) show an example of the implementation structure of a common-mode noise filter on a circuit board according to an embodiment of the present invention. Figure 4(A) is a plan view, and Figure 4(B) is a side cross-sectional view. In Figure 4(B), the common-mode noise filter 10 is shown in a simplified manner by cutting it into multiple cross-sections in order to clearly show the implementation structure of the multiple pad electrodes.

[0130] The common-mode noise filter 10 is constructed from a substrate 90 made of a semiconductor substrate, as described above. The common-mode noise filter 10 has a rectangular parallelepiped shape with a surface F901. The first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG are exposed on surface F901.

[0131] The circuit board 50 comprises an insulating layer 51 and an insulating layer 52. The insulating layer 51 and the insulating layer 52 are laminated together. The insulating layer 51 is the surface layer of the circuit board 50. The surface of the insulating layer 51 is the surface F50 of the circuit board 50.

[0132] Multiple signal terminal land electrodes PAD1, PAD2, PAD3, PAD4 and a reference potential land electrode PADG are arranged on the surface F50 of the circuit board 50.

[0133] Multiple signal terminal land electrodes PAD1, PAD2, PAD3, and PAD4 are positioned to form a rectangle in a plan view. Signal terminal land electrodes PAD1 and PAD2 are positioned at the same interval as the first pad electrode PDP1 and the second pad electrode PDP2. Signal terminal land electrodes PAD3 and PAD4 are positioned at the same interval as the third pad electrode PDP3 and the fourth pad electrode PDP4.

[0134] The reference potential land electrode PADG is positioned to include the center of the rectangle formed by the arrangement pattern of the multiple signal terminal land electrodes PAD1, PAD2, PAD3, and PAD4.

[0135] Strip-shaped wiring electrodes PT1, PT2, PT3, and PT4 are arranged on the surface F50 of the circuit board 50. Wiring electrode PT1 is connected to the first pad electrode PDP1. Wiring electrode PT2 is connected to the second pad electrode PDP2. Wiring electrode PT3 is connected to the third pad electrode PDP3. Wiring electrode PT4 is connected to the fourth pad electrode PDP4.

[0136] Inside the circuit board 50, more specifically at the interface between the insulating layer 51 and the insulating layer 52, a ground electrode PT50G for the circuit board is placed. The ground electrode PT50G for the circuit board is placed over substantially the entire interface between the insulating layer 51 and the insulating layer 52.

[0137] A ground via conductor VIA 50G is placed inside the circuit board 50, more specifically in the insulating layer 51. The ground via conductor VIA 50G is columnar in shape and penetrates the insulating layer 51 in the thickness direction. In a plan view, the ground via conductor VIA 50G overlaps the ground pad electrode PDG. The ground via conductor VIA 50G connects the ground pad electrode PDG and the circuit board ground electrode PT 50G.

[0138] The common-mode noise filter 10 is mounted on the circuit board 50. In this case, the first pad electrode PDP1 is mounted facing the signal terminal land electrode PAD1 using an external connection conductor SB1. The second pad electrode PDP2 is mounted facing the signal terminal land electrode PAD2 using an external connection conductor SB2. The third pad electrode PDP3 is mounted facing the signal terminal land electrode PAD3 using an external connection conductor. The fourth pad electrode PDP4 is mounted facing the signal terminal land electrode PAD4 using an external connection conductor. The ground pad electrode PDG is mounted facing the reference potential land electrode PADG using an external connection conductor SBG.

[0139] External connection conductors SB1, SB2, SBG, and other external connection conductors are formed, for example, by solder bumps.

[0140] In this configuration, the ground electrode PT50G for the circuit board 50 becomes the electrode that determines the reference potential of the common-mode noise filter 10. Therefore, the ground via conductor VIA50G functions as the inductor 300 of the common-mode noise filter 10.

[0141] With the above configuration, the ground via conductor VIA50G overlaps with the ground pad electrode PDG in a plan view. Therefore, the ground via conductor VIA50G is positioned at a structurally and electrically equidistant location with respect to the multiple first filter circuit electrode groups and the multiple second filter circuit electrode groups of the common-mode noise filter 10. Furthermore, the ground via conductor VIA50G is positioned at a structurally and electrically equidistant location with respect to the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, and the fourth pad electrode PDP4.

[0142] As a result, the electrical characteristics of the common-mode noise filter 10 are the same in the region on the side of the first pad electrode PDP1 and the third pad electrode PDP3 as in the region on the side of the second pad electrode PDP2 and the fourth pad electrode PDP4. Therefore, the common-mode noise filter 10 can achieve excellent filtering characteristics.

[0143] In circuit terms, the inductor 300 of the common-mode noise filter 10 is positioned at an electrical equidistant location with respect to the electrodes of the multiple first filter circuits and the multiple second filter circuits. Furthermore, the inductor 300 of the common-mode noise filter 10 is positioned at an electrical equidistant location with respect to the first terminal P1, the second terminal P2, the third terminal P3, and the fourth terminal P4.

[0144] As a result, the electrical characteristics of the common-mode noise filter 10 are the same in the region on the side of the first terminal P1 and the third terminal P3 as they are in the region on the side of the second terminal P2 and the fourth terminal P4. Therefore, the common-mode noise filter 10 can achieve excellent filtering characteristics.

[0145] Furthermore, in the above configuration, the inductor 300 is made up of the circuit board 50 on which the common-mode noise filter 10 is mounted. This makes it easier to set the inductance (impedance) of the inductor element to a desired value without changing the shape of the circuit board 90 that constitutes the common-mode noise filter 10. Therefore, it becomes easier to achieve more desired filter characteristics.

[0146] Furthermore, the external connection conductor SBG, which connects the ground pad electrode PDG and the reference potential land electrode PADG, can also function as an inductor 300 in the common-mode noise filter 10. In this case, the common-mode noise filter 10 can achieve excellent filter characteristics without using a circuit board 50.

[0147] Furthermore, the common-mode noise filter 10 has a configuration in which the electrodes for the shunt capacitor of multiple first filter circuit electrode groups and multiple second filter circuit electrode groups are sandwiched between reference potential connection electrodes PtCG1 and PtCG2. As a result, the common-mode noise filter 10 can increase the capacitance of the shunt capacitor without unnecessarily increasing the planar area of ​​the substrate 90.

[0148] Furthermore, the electrodes for the shunt capacitors of the multiple first filter circuit electrode groups and the multiple second filter circuit electrode groups, as well as the reference potential connection electrodes PtCG1 and PtCG2, are symmetrical with respect to the Y-axis reference line AxeY and the X-axis reference line AxeX, respectively. In addition, multiple sets of via conductors VIA1, wiring electrodes Ptcnt, and via conductors VIA2 connecting the reference potential connection electrode PtCG1 and the reference potential connection electrode PtCG2 are arranged on the Y-axis reference line AxeY and are arranged symmetrically with respect to the X-axis reference line AxeX. As a result, the common-mode noise filter 10 can maintain the electrical symmetry described above.

[0149] Therefore, the common-mode noise filter 10 can achieve excellent filtering characteristics in a compact form factor.

[0150] In the above description of the embodiment, a three-stage common-mode noise filter was used as an example, but the number of stages is not limited to three.

[0151] Figure 5 is a schematic diagram showing the configuration of an n-stage common-mode noise filter. As shown in Figure 5, the n-stage common-mode noise filter 10A is constructed from a substrate 90A made of a semiconductor substrate. The common-mode noise filter 10A includes a first pad electrode PDP1, a second pad electrode PDP2, a third pad electrode PDP3, a fourth pad electrode PDP4, and a ground pad electrode PDG. The arrangement pattern of the first pad electrode PDP1, the second pad electrode PDP2, the third pad electrode PDP3, the fourth pad electrode PDP4, and the ground pad electrode PDG of the common-mode noise filter 10A is the same as that of the common-mode noise filter 10 described above.

[0152] In the region RELs1Cm1 between the first pad electrode PDP1 and the second pad electrode PDP2, a series inductor in the n-stage first filter circuit electrode group and a capacitor connected in parallel to the series inductor are arranged.

[0153] In the region RELs2Cm2 between the third pad electrode PDP3 and the fourth pad electrode PDP4, a series inductor in the n-stage second filter circuit electrode group and a capacitor connected in parallel to the series inductor are arranged.

[0154] In region RECs1Cs2, between region RELs1Cm1 and region RELs2Cm2, the shunt capacitors of the n-stage first filter circuit electrode group and the n-stage second filter circuit electrode group, as well as the reference potential connection electrodes PtCG1 and PtCG2, are arranged. The ground pad electrode PDG is positioned to overlap with the reference potential connection electrodes PtCG1 and PtCG2.

[0155] With this configuration, the n-stage common-mode noise filter 10A can achieve excellent filtering characteristics, similar to the common-mode noise filter 10 described above.

[0156] <1> A common-mode noise filter mounting structure comprising: a substrate on which a common-mode noise filter using a first differential signal and a second differential signal is formed; and a circuit board on which the substrate is mounted, wherein the common-mode noise filter comprises: a first pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the first differential signal; a second pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the first differential signal; a third pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the second differential signal; a fourth pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the second differential signal; a first filter circuit electrode group formed on the substrate and connected to the first pad electrode and the second pad electrode, constituting the first filter of the common-mode noise filter; a second filter circuit electrode group formed on the substrate and connected to the third pad electrode and the fourth pad electrode, constituting the second filter of the common-mode noise filter; and a ground pad electrode connecting the first filter circuit electrode group and the second filter circuit electrode group to a reference potential. The circuit board comprises an inductor element connected in series with the ground pad electrode, the substrate having a first direction and a second direction parallel to the main surface and mutually orthogonal, the first pad electrode and the second pad electrode are arranged side by side in the first direction, the first filter circuit electrode group is arranged between the first pad electrode and the second pad electrode in the first direction, the third pad electrode and the fourth pad electrode are arranged side by side in the first direction, the second filter circuit electrode group is arranged between the third pad electrode and the fourth pad electrode in the first direction, the first pad electrode and the third pad electrode are arranged side by side in the second direction, the second pad electrode and the fourth pad electrode are arranged side by side in the second direction, the ground pad electrode is arranged between the first filter circuit electrode group and the second filter circuit electrode group in the second direction, the circuit board comprises a reference potential land electrode formed on the surface of the circuit board on which the ground pad electrode is mounted, and a circuit board ground electrode formed within the circuit board.A common-mode noise filter mounting structure comprising a columnar ground via conductor extending in the thickness direction of the circuit board, which connects the reference potential land electrode and the ground electrode for the circuit board, wherein the inductor element is configured using the ground via conductor.

[0157] <2> The common-mode noise filter implementation structure according to <1>, wherein the ground pad electrode is positioned equidistant from the first pad electrode, the second pad electrode, the third pad electrode, and the fourth pad electrode.

[0158] <3> The common-mode noise filter mounting structure according to <1> or <2>, comprising a connecting conductor for connecting the ground pad electrode and the reference potential land electrode, wherein the inductor element is configured using the ground via conductor and the connecting conductor.

[0159] <4> The mounting structure for the common mode noise filter according to <3>, wherein the first filter circuit electrode group and the second filter circuit electrode group are provided in the same number in multiples, the multiple first filter circuit electrode groups are connected in series between the first pad electrode and the second pad electrode along the first direction, the multiple second filter circuit electrode groups are connected in series between the third pad electrode and the fourth pad electrode along the first direction, and when the common mode noise filter is mounted on the circuit board, the ground via conductor of the circuit board is positioned between the central first filter circuit electrode group of the multiple first filter circuit electrode groups and the central second filter circuit electrode group of the multiple second filter circuit electrode groups in the common mode noise filter, with the mounting surface viewed from above.

[0160] <5> A first pad electrode formed to be exposed on the surface of a substrate and constituting one terminal of a first differential signal; a second pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the first differential signal; a third pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of a second differential signal; a fourth pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the second differential signal; a first filter circuit electrode group formed on the substrate and connected to the first pad electrode and the second pad electrode, constituting the first filter of a common mode noise filter; a second filter circuit electrode group formed on the substrate and connected to the third pad electrode and the fourth pad electrode, constituting the second filter of a common mode noise filter; a ground pad electrode connecting the first filter circuit electrode group and the second filter circuit electrode group to a reference potential; and an inductor element connected in series with the ground pad electrode, wherein the substrate has a first direction and a second direction parallel to the main surface and orthogonal to each other, and the first pad electrode and the second pad electrode are arranged side by side in the first direction. A common-mode noise filter wherein the first filter circuit electrode group is positioned between the first pad electrode and the second pad electrode in the first direction, the third pad electrode and the fourth pad electrode are positioned side by side in the first direction, the second filter circuit electrode group is positioned between the third pad electrode and the fourth pad electrode in the first direction, the first pad electrode and the third pad electrode are positioned side by side in the second direction, the second pad electrode and the fourth pad electrode are positioned side by side in the second direction, and the ground pad electrode and the inductor element are positioned at an intermediate position between the first filter circuit electrode group and the second filter circuit electrode group in the second direction.

[0161] <6> The common-mode noise filter according to <5>, wherein the ground pad electrode and the inductor element are positioned equidistant from the first pad electrode, the second pad electrode, the third pad electrode, and the fourth pad electrode in a plan view.

[0162] <7> The common-mode noise filter according to <5> or <6>, comprising an external connection conductor formed on the ground pad electrode, wherein the inductor element is composed of the external connection conductor.

[0163] <8> The common-mode noise filter described in <7>, wherein the external connection conductor is a solder bump.

[0164] <9> The common-mode noise filter according to any one of <5> to <8>, wherein the first filter circuit electrode group and the second filter circuit electrode group are provided in the same number in multiples, the multiple first filter circuit electrode groups are connected in series between the first pad electrode and the second pad electrode along the first direction, the multiple second filter circuit electrode groups are connected in series between the third pad electrode and the fourth pad electrode along the first direction, and the inductor element is positioned between the central first filter circuit electrode group of the multiple first filter circuit electrode groups and the central second filter circuit electrode group of the multiple second filter circuit electrode groups.

[0165] 10, 10A: Common-mode noise filter 21: First common-mode noise filter 21T1: First T-type filter circuit 21T2: Second T-type filter circuit 22: Second common-mode noise filter 22T1: Third T-type filter circuit 22T2: Fourth T-type filter circuit 23: Third common-mode noise filter 23T1: Fifth T-type filter circuit 23T2: Sixth T-type filter circuit 50: Circuit board 51, 52: Insulator layer 90, 90A: Substrate 91, 92, 93, 94: Insulator layer 300, 311, 312, 314, 315, 321, 322, 324, 325, 331, 332, 334, 335: Inductor 313, 316, 323, 326, 333, 336: Capacitor 317, 318, 327, 328, 337, 338: Shunt capacitor 900: Substrate AxeX: X-axis reference line AxeY: Y-axis reference line CLY1: First conductor layer CLY2: Second conductor layer CLY3: Third conductor layer F50: Surface F901: Surface LINECS1: Section line LINECS2: Section line OPG: Aperture P1: First terminal P2: Second terminal P3: Third terminal P4: Fourth terminal PAD1, PAD2, PAD3, PAD4: Land electrodes for signal terminals PADG: Land electrode for reference potential PDG: Ground pad electrode PDP1: First pad electrode PDP2: Second pad electrode PDP3: Third pad electrode PDP4: Fourth pad electrode PT1, PT2, PT3, PT4: Wiring electrodes PT50G: Ground electrode for circuit board Pt311, Pt312, Pt314, Pt315, Pt321, Pt322, Pt324, Pt325, Pt331, Pt332, Pt334, Pt335: Inductor electrode Pt313, Pt316, Pt323, Pt326, Pt333, Pt336: Capacitor electrode Pt317, Pt318, Pt327, Pt328, Pt337, Pt338: Filter side electrode PtCG1, PtCG2: Reference potential connection electrode Ptcnt: Wiring electrode RELs1Cm1, RELs2Cm2, RECs1Cs2: Region SB1, SB2, SBG: Conductor for external connection VIA1, VIA2: Via conductors; VIA50G: Ground via conductor

Claims

1. A common-mode noise filter mounting structure comprising: a substrate on which a common-mode noise filter using a first differential signal and a second differential signal is formed; and a circuit board on which the substrate is mounted, wherein the common-mode noise filter comprises: a first pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the first differential signal; a second pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the first differential signal; a third pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the second differential signal; a fourth pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the second differential signal; a first filter circuit electrode group formed on the substrate and connected to the first pad electrode and the second pad electrode, constituting the first filter of the common-mode noise filter; a second filter circuit electrode group formed on the substrate and connected to the third pad electrode and the fourth pad electrode, constituting the second filter of the common-mode noise filter; and a ground pad electrode connecting the first filter circuit electrode group and the second filter circuit electrode group to a reference potential. The circuit board comprises an inductor element connected in series with the ground pad electrode, the substrate having a first direction and a second direction parallel to the main surface and mutually orthogonal, the first pad electrode and the second pad electrode are arranged side by side in the first direction, the first filter circuit electrode group is arranged between the first pad electrode and the second pad electrode in the first direction, the third pad electrode and the fourth pad electrode are arranged side by side in the first direction, the second filter circuit electrode group is arranged between the third pad electrode and the fourth pad electrode in the first direction, the first pad electrode and the third pad electrode are arranged side by side in the second direction, the second pad electrode and the fourth pad electrode are arranged side by side in the second direction, the ground pad electrode is arranged between the first filter circuit electrode group and the second filter circuit electrode group in the second direction, the circuit board comprises a reference potential land electrode formed on the surface of the circuit board on which the ground pad electrode is mounted, and a circuit board ground electrode formed within the circuit board.A common-mode noise filter mounting structure comprising: a columnar ground via conductor extending in the thickness direction of the circuit board, which connects the reference potential land electrode and the ground electrode for the circuit board, wherein the inductor element is constructed using the ground via conductor.

2. The common-mode noise filter mounting structure according to claim 1, wherein the ground pad electrode is positioned equidistant from the first pad electrode, the second pad electrode, the third pad electrode, and the fourth pad electrode.

3. The common-mode noise filter mounting structure according to claim 1 or claim 2, comprising a connecting conductor for connecting the ground pad electrode and the reference potential land electrode, wherein the inductor element is configured using the ground via conductor and the connecting conductor.

4. The mounting structure for a common mode noise filter according to claim 3, wherein the first filter circuit electrode group and the second filter circuit electrode group are provided in the same number in multiples, the multiple first filter circuit electrode groups are connected in series between the first pad electrode and the second pad electrode along the first direction, the multiple second filter circuit electrode groups are connected in series between the third pad electrode and the fourth pad electrode along the first direction, and when the common mode noise filter is mounted on the circuit board, the ground via conductor of the circuit board is positioned between the central first filter circuit electrode group of the multiple first filter circuit electrode groups and the central second filter circuit electrode group of the multiple second filter circuit electrode groups in the common mode noise filter.

5. The substrate comprises: a first pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the first differential signal; a second pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the first differential signal; a third pad electrode formed to be exposed on the surface of the substrate and constituting one terminal of the second differential signal; a fourth pad electrode formed to be exposed on the surface of the substrate and constituting the other terminal of the second differential signal; a first filter circuit electrode group formed on the substrate and connected to the first pad electrode and the second pad electrode, constituting the first filter of the common mode noise filter; a second filter circuit electrode group formed on the substrate and connected to the third pad electrode and the fourth pad electrode, constituting the second filter of the common mode noise filter; a ground pad electrode connecting the first filter circuit electrode group and the second filter circuit electrode group to a reference potential; and an inductor element connected in series with the ground pad electrode, wherein the substrate has a first direction and a second direction parallel to the main surface and mutually orthogonal to each other, and the first pad electrode and the second pad electrode are arranged side by side in the first direction. A common-mode noise filter wherein the first filter circuit electrode group is positioned between the first pad electrode and the second pad electrode in the first direction, the third pad electrode and the fourth pad electrode are positioned side by side in the first direction, the second filter circuit electrode group is positioned between the third pad electrode and the fourth pad electrode in the first direction, the first pad electrode and the third pad electrode are positioned side by side in the second direction, the second pad electrode and the fourth pad electrode are positioned side by side in the second direction, and the ground pad electrode and the inductor element are positioned at an intermediate position between the first filter circuit electrode group and the second filter circuit electrode group in the second direction.

6. The common-mode noise filter according to claim 5, wherein the ground pad electrode and the inductor element are positioned equidistant from the first pad electrode, the second pad electrode, the third pad electrode, and the fourth pad electrode in a plan view.

7. The common-mode noise filter according to claim 5 or claim 6, comprising an external connection conductor formed on the ground pad electrode, wherein the inductor element is composed of the external connection conductor.

8. The common-mode noise filter according to claim 7, wherein the external connection conductor is a solder bump.

9. The common-mode noise filter according to any one of claims 5 to 8, wherein the first filter circuit electrode group and the second filter circuit electrode group are provided in the same number in multiples, the multiple first filter circuit electrode groups are connected in series between the first pad electrode and the second pad electrode along the first direction, the multiple second filter circuit electrode groups are connected in series between the third pad electrode and the fourth pad electrode along the first direction, and the inductor element is positioned between the central first filter circuit electrode group of the multiple first filter circuit electrode groups and the central second filter circuit electrode group of the multiple second filter circuit electrode groups.

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