JP2017037981A - Printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board mounted with an additional circuit, capable of improving balancing of a differential line even when high-density mounting is implemented.SOLUTION: A first metal pattern 51 is formed at a position beneath a first connection conductor 21 and a first component 31 of a layer between a layer mounted with a wiring and a component and a ground layer 70. A second metal pattern 52 is formed at a position beneath a second connection conductor 22 and a second component 32 of a layer between a layer mounted with a wiring and a component and the ground layer 70. The first metal pattern 51 and the second metal pattern 52 are electrically connected with the ground layer 70 through a first veer 41 and a second veer 42, respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printed circuit board having a differential line to which components are connected and a ground layer.

  As a printed circuit board, there is one using differential signal transmission in which a signal having the same amplitude and opposite phase is propagated and communicated with a pair of signal wirings. In this differential signal transmission, the amplitude of the voltage per line can be reduced by taking the difference between the paired signals on the signal receiving side, and radiating by pairing the phase signals. The electromagnetic field cancels out and radiation noise can be suppressed. Furthermore, there is an advantage that the influence of external noise can be canceled by taking the difference between the paired signals.

  However, in differential signal transmission, if the symmetry of the line structure breaks, high-speed signals cannot be transmitted, and the common mode noise propagates on the differential line due to the deterioration of the balance of the differential line of the communication circuit. The radiation noise from the differential line increases, and the noise resistance of the differential line decreases. For this reason, in a high-speed differential interface including a high frequency component in a signal, it is necessary to design a line on the substrate so as not to impair the symmetry of the line structure.

  Conventionally, as a printed circuit board having such a differential line, a layer on which a first conductor and a second conductor constituting the differential line are mounted and a ground layer are sandwiched between the first and second layers. In some cases, an island-shaped conductor is provided in advance by patterning along the two conductors, and a capacitive stub is formed by the island-shaped conductor portion (see, for example, Patent Document 1).

JP 2008-153386 A

  In the conventional printed circuit board, the balance of the differential line is improved by changing the shape, position, and interval of the capacitive stub and adjusting the capacitance of both wirings. However, when an additional circuit such as a component is mounted on the wiring, there is a problem that the prepared stub cannot be adjusted due to trial and error after creating the board, and even if it can be adjusted, it is difficult to evaluate. It was.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a printed circuit board capable of improving the balance of differential lines even when an additional circuit is mounted. And

  The printed circuit board according to the present invention is provided on the first conductor side across the differential line, the differential line composed of the first conductor and the second conductor formed in a layer for mounting wiring and components. The first component and the second component provided on the second conductor side, the first connection conductor connecting the first component and the first conductor, the second component and the second conductor The first connection conductor is connected to the first connection conductor and the first component. The first connection conductor is connected to the first connection conductor and the first component. And a second metal pattern provided in a layer between the wiring and component mounting layer and the ground layer, and formed at a position immediately below the second connection conductor and the second component. The first metal pattern and the second metal pattern are electrically connected to the ground layer, respectively. It is obtained by the.

  In the printed circuit board according to the present invention, first and second metal patterns are respectively formed immediately below the first and second connection conductors and the first and second components, and the first and second metal patterns are formed. Since it is electrically connected to the ground layer, the balance of the differential line can be improved even when an additional circuit is mounted.

It is a top view which shows the printed circuit board by Embodiment 1 of this invention. It is the sectional view on the AA line of FIG. It is a top view which shows the printed circuit board by Embodiment 2 of this invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is an enlarged plan view of the printed circuit board by Embodiment 2 of this invention. It is a top view of the printed circuit board by Embodiment 3 of this invention. It is CC sectional view taken on the line of FIG. It is a top view of the printed circuit board by Embodiment 4 of this invention. It is the DD sectional view taken on the line of FIG. It is a top view of the printed circuit board by Embodiment 5 of this invention. It is the EE sectional view taken on the line of FIG.

Embodiment 1 FIG.
1 and 2 are configuration diagrams showing a printed circuit board according to Embodiment 1 of the present invention. FIG. 1 is a plan view schematically showing the printed circuit board. FIG. 2 is a cross-sectional view taken along line AA of FIG. FIG.
1 and 2, the printed circuit board 1 has a layer for mounting wiring and components and a ground layer 70. The first conductor 11 and the second conductor 12 form a differential line formed in a layer for mounting wiring and components. The first component 31 and the second component 32 are placed at positions close to each other across the differential line. The first connection conductor 21 connects the first component 31 and the first conductor 11. The second connection conductor 22 connects the second component 32 and the second conductor 12. The first metal pattern 51 is formed at a position directly below the first connection conductor 21 and the first component 31 in a layer between the layer on which wiring and components are mounted and the ground layer 70. The second metal pattern 52, in a layer between the layers and the ground layer 70 to implement the wiring and components is formed at a position immediately below the second connection conductor 22 and the second part 32. The first via 41 electrically connects the first metal pattern 51 and the ground layer 70. The second via 42 electrically connects the second metal pattern 52 and the ground layer 70.

  Thus, the printed circuit board 1 includes the first conductor 11, the second conductor 12, the first component 31, the second component 32, the first connection conductor 21, and the first conductor 11 as layers for mounting wiring and components. A first layer in which two connection conductors 22 are arranged, a second layer in which the second metal pattern 52 is formed, a third layer in which the first metal pattern 51 is formed, and a ground layer as a ground layer And a first via 41 between the third layer and the fourth layer, and a second via 42 between the second layer and the second layer. The four layers are electrically connected. It is assumed that there is a dielectric 60 between each layer.

  Here, when the first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, the ground layer at the connection point of the first conductor 11 of the first connection conductor 21. The capacitance between the first connection conductor 21 and the first component 31 depends on the area of the first connection conductor 21 and the first component 31 and the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51. To do. Similarly, when the second component 32 is disposed within the area of the second metal pattern 52, the capacitance between the second connection conductor 22 and the ground layer 70 at the connection point of the second conductor 12. Depends on the area of the second connection conductor 22 and the second component 32 and the distance between the second connection conductor 22 and the second component 32 and the second metal pattern 52.

  For example, as shown in FIG. 1, when the first connection conductor 21 is larger than the second connection conductor 22, the balance of the differential line deteriorates, but in the present embodiment, the first connection conductor 21. And the area of the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, the area of the second connection conductor 22 and the second component 32, The distance between the second connection conductor 22 and the second component 32 and the second metal pattern 52 is adjusted, and the first connection conductor 21 and the first component 31 and the first metal pattern 51 are Between the second connection conductor 22 and the second component 32 and the second metal pattern 52 (this is the second capacitance). ) Is within the design target range, the balance of the differential line can be increased.

  Here, setting the difference between the first capacity and the second capacity within the range of the design target is as follows. That is, radiation noise from a printed circuit board based on various conditions such as radiation noise standards required for the printed circuit board, noise radiation efficiency from the printed circuit board, or the structure of the housing in which the printed circuit board is housed. A design target is set to suppress the value within a preset regulation value. Here, when “the difference in capacitance is 0 = the first capacitor and the second capacitor are adjusted equally”, theoretically, radiation noise from the printed circuit board is set to zero, and such adjustment is also performed. It is included within the scope of the design goal. However, in actual design, there is a relationship with cost, work efficiency, and the like, and the radiation noise is allowed within a certain range. This range of values is a value within the range of the design target.

  Hereinafter, each example for adjusting the difference between the first capacity and the second capacity to be within the range of the design target will be described.

First, the area of the first metal pattern 51 is the same or larger than the total area of the first connection conductor 21 and the first component 31, and the area of the second metal pattern 52 is the second connection conductor 22. A case where the same or larger than the combined area of the second part 32 will be described.
As described above, the first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, and the second connection conductor 22 and the second component 32 are formed of the second metal pattern. When arranged in the area, the capacitance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, that is, the first capacitance, the second connection conductor and the second By adjusting the capacitance between the component 32 and the second metal pattern 52, that is, the difference between the second capacitance and the second capacitance to be within the design target range, the balance of the differential line is increased. be able to.

At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the second connection conductor 22 and the second component 32 and the distance between the second connection conductor 22 and the second component 32 and the second metal pattern 52 can be mentioned.
As described above, when the connection conductor and the component are arranged in the area of the metal pattern, only the capacitance generated between the connection conductor and the component and the metal pattern needs to be considered.

  Next, the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, or the area of the second metal pattern 52 is the second connection conductor 22 and the second area. A case where the area is smaller than the total area of the parts 32 or a case where both are small will be described.

  If the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, all or part of at least one of the first connection conductor 21 and the first component 31. Is disposed outside the area of the first metal pattern 51 and the area of the second metal pattern 52 is smaller than the combined area of the second connection conductor 22 and the second component 32, the second connection All or part of at least one of the conductor 22 and the second component 32 may be disposed outside the area of the second metal pattern 52.

  For example, when at least a part of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, the portion between the portion disposed outside the area and the ground layer 70 is disposed. The capacitance generated in the first connection conductor 21 and the first component 31 and the first metal pattern 51 is generated in addition to the capacitance between the first connection conductor 21 and the first component 31. Further, for example, when at least a part of the second connection conductor 22 and the second component 32 is disposed outside the area of the second metal pattern 52, the portion disposed outside the area and the ground layer 70. The capacitance generated between the second connection conductor 22 and the second component 32 and the second metal pattern 52 is generated.

Thus, when the connection conductor and the component are arranged outside the area of the metal pattern, it is not sufficient to consider only the capacitance between the connection conductor and the component and the metal pattern. It is necessary to consider the combined capacitance with the capacitance generated between the ground layer 70 and the ground layer 70.
Therefore, first, the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, and the area of the second metal pattern 52 is the same as that of the second connection conductor 22. A case where the area is smaller than the combined area of the second parts 32 will be described.

  A part of at least one of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, and at least one of the second connection conductor 22 and the second component 32. Is disposed outside the area of the second metal pattern 52, the portion of the first connection conductor 21 and the first component 31 disposed outside the area of the first metal pattern 51 and the ground layer 70. Between the first connection conductor 21 and the first component 31 and the capacitance between the first metal pattern 51, that is, the first capacitance and the second connection. The capacitance generated between the portion of the conductor 22 and the second component 32 arranged outside the area of the second metal pattern 52 and the ground layer 70, the second connection conductor 22 and the second component 32, Second metal Combined capacitance of the capacitance between the turns 52, namely that the difference between the second capacitor is adjusted to be within the design target, it is possible to increase the balance of the differential lines.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the portion of the first connection conductor 21 and the first component 31 arranged outside the area of the first metal pattern 51 and the distance between the portion arranged outside the area and the ground layer 70 The area of the second connection conductor and the second component 32, the distance between the second connection conductor 22 and the second component 32 and the second metal pattern 52, and the second connection conductor 22 The area of the part arrange | positioned outside the area of the 2nd metal pattern 52 in the 2nd component 32, and the distance between the part arrange | positioned outside the said area, and the ground layer 70 are mentioned.

  Next, the area of the first metal pattern 51 is the same as or larger than the total area of the first connection conductor 21 and the first component 31, while the area of the second metal pattern 52 is the second. A case where the area is smaller than the combined area of the connection conductor 22 and the second component 32 will be described.

  The first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, and at least one part of the second connection conductor 22 and the second component 32 is the second. When arranged outside the area of the metal pattern 52, the capacitance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, that is, the first capacitance and the second connection. The capacitance generated between the portion of the conductor 22 and the second component 32 arranged outside the area of the second metal pattern 52 and the ground layer 70, the second connection conductor 22 and the second component 32, The balance between the second metal pattern 52 and the second capacitor is adjusted so that the difference between the capacitance and the second capacitance is within the design target range, thereby increasing the balance of the differential line. Can do.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and , The area of the second component 32, the distance between the second connection conductor 22 and the second component 32 and the second metal pattern 52, and the second connection conductor 22 and the second component 32. The area of the part arrange | positioned outside the area of the 2nd metal pattern 52, and the distance between the part arrange | positioned outside the said area, and the ground layer 70 are mentioned.

  In addition, the 1st conductor 11 demonstrated so far, the 1st component 31 relevant to this, the 1st connection conductor 21, the 1st metal pattern 51, the 2nd conductor 12, and the 2nd relevant to this For the component 32, the second connection conductor 22, and the second metal pattern 52, for example, even if the interpretation of the relationship between the arrangement of the first and second metal patterns 51 and 52 and the size of the area is reversed, the condition contents Similarly, the balance of the differential line can be increased.

  In the first embodiment, with respect to the first conductor 11 and the second conductor 12 forming the differential line, a pair of the first component 31 and the second component 32, the first connection conductor 21 and the second conductor The mounting of the connection conductor 22, the first metal pattern 51, and the second metal pattern 52 has been described. There may be cases where multiple wirings or other parts are mounted on this printed circuit board, or connection conductors or parts may be mounted only on one side of the differential line. The overall balance can be increased by improving the balance.

  In the first embodiment, mounting is described for a printed circuit board having a four-layer structure. However, the printed circuit board is not limited to four layers and includes other layers not directly used in the mounting portion described here. It can also be applied to.

  Furthermore, in the above example, the first metal pattern 51 is provided on the third layer, and the second metal pattern 52 is provided on the second layer. On the contrary, the first metal pattern 51 is provided on the second layer. The second metal pattern 52 may be provided on the third layer, and the first metal pattern 51 and the second metal pattern 52 may be provided on the second layer or the third layer, for example. Alternatively, they may be provided in the same layer.

  As described above, according to the printed circuit board of the first embodiment, the differential line composed of the first conductor and the second conductor formed on the wiring and component mounting layers, and the differential line sandwiched between A first component provided on the first conductor side, a second component provided on the second conductor side, a first connection conductor connecting the first component and the first conductor; A second connection conductor for connecting the second component and the second conductor, and a layer between the layer on which the wiring and the component are mounted and the ground layer, and the first connection conductor and the first component; Provided in the first metal pattern formed immediately below, the layer between the wiring and component mounting layer and the ground layer, and formed at the position directly below the second connection conductor and the second component. A second metal pattern, and the first metal pattern and the second metal pattern are grounded respectively. Since to be electrically connected to the layer, even if the additional circuit is mounted, it is possible to improve the balance of the differential lines.

  Further, according to the printed circuit board of the first embodiment, the first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are When arranged in the area of the second metal pattern, a first capacitance that is a capacitance generated between the first connection conductor and the first component and the first metal pattern, and a second connection Since the difference between the second capacitance, which is the capacitance generated between the conductor and the second component, and the second metal pattern is set to a value within the setting range, the balance of the differential line is improved. Thus, common mode noise on the differential line can be suppressed, radiation noise from the differential line can be suppressed, and noise resistance of the differential line can be improved.

  Further, according to the printed circuit board of the first embodiment, at least a part of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second When at least a part of the connection conductor and the second component is disposed outside the area of the second metal pattern, the first metal pattern of the first connection conductor and the first component And a capacitance generated between the portion arranged outside the area and the ground layer, and a capacitance generated between the first connection conductor and the first component and the first metal pattern. A certain first capacitance, a capacitance generated between a portion of the second connection conductor and the second component arranged outside the area of the second metal pattern and the ground layer, and a second connection Between the conductor and the second component and the second metal pattern Since the difference between the second capacitance, which is the combined capacitance with the capacitance, is set to a value within the setting range, the balance of the differential line is improved, the common mode noise on the differential line is suppressed, While suppressing the radiation noise from a differential line, the noise tolerance of a differential line can be improved.

  Further, according to the printed circuit board of the first embodiment, the first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are Among these, when at least a part of any one of them is arranged outside the area of the second metal pattern, the first capacitance that is generated between the first connection conductor and the first component and the first metal pattern. 1, the second connection conductor and the second component, the capacitance generated between the portion of the second metal pattern disposed outside the area of the second metal pattern and the ground layer, the second connection conductor and Since the difference between the second capacitance, which is the combined capacitance of the capacitance generated between the second component and the second metal pattern, is set to a value within the setting range, the balance of the differential line To suppress common mode noise on the differential line, Suppresses the morphism noise, it is possible to improve the noise resistance of the differential lines.

  According to the printed circuit board of the first embodiment, at least a part of at least one of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second When the connection conductor and the second component are disposed within the area of the second metal pattern, the capacitance generated between the portion disposed outside the area of the first metal pattern and the ground layer, and the first A first capacitance that is a combined capacitance of the connection conductor and the first component and the capacitance generated between the first component and the first metal pattern, and the second connection conductor and second component and the second metal pattern. The difference from the second capacitance, which is the electrostatic capacitance generated between the two, is set to a value within the setting range, so that the balance of the differential line is improved and common mode noise on the differential line is suppressed. In addition to suppressing radiation noise from the differential line, It is possible to improve the noise resistance.

  Further, according to the printed circuit board of the first embodiment, since the first metal pattern and the second metal pattern are formed in the same layer, the balance of the differential line is improved, and the differential It is possible to suppress common mode noise on the line, suppress radiation noise from the differential line, and improve noise resistance of the differential line. In addition, the capacitance between the metal pattern and the ground layer depends only on the area. If the area is within the design target range, the difference in capacitance is within the design target range, and therefore the design is easy. .

  Further, according to the printed circuit board of the first embodiment, since the first metal pattern and the second metal pattern are formed in different layers, the balance of the differential line is improved, and the differential line The upper common mode noise can be suppressed, radiation noise from the differential line can be suppressed, and noise resistance of the differential line can be improved.

Embodiment 2. FIG.
3 and 4 are configuration diagrams showing an example of a printed circuit board according to Embodiment 2 of the present invention. FIG. 3 is a plan view schematically showing the printed circuit board, and FIG. 4 is a cross-sectional view taken along the line BB of FIG.

  3 and 4, the printed circuit board 1 has a layer for mounting wiring and components and a ground layer 70 as in the first embodiment. The first conductor 11 and the second conductor 12 form a differential line formed in a layer for mounting wiring and components. The first component 31 and the second component 32 are placed at positions close to each other across the differential line. The first connection conductor 21 connects the first component 31 and the first conductor 11. The second connection conductor 22 connects the second component 32 and the second conductor 12. The first metal pattern 51 is formed at a position directly below the first connection conductor 21 and the first component 31 in a layer between a layer for mounting wiring and components and a ground layer. The second metal pattern 52 is formed at a position immediately below the second connection conductor 22 and the second component 32 in a layer between the wiring and component mounting layers and the ground layer 70. The first via 41 electrically connects the first metal pattern 51 and the ground layer 70. The second via 42 electrically connects the second conductor 12 and the second metal pattern 52.

  As described above, the printed circuit board 1 according to the second embodiment includes the first conductor 11, the second conductor 12, the first component 31, the second component 32, and the first layer as layers for mounting wiring and components. A first layer in which the connection conductor 21 and the second connection conductor 22 are arranged, a second layer for adjusting the distance between the metal pattern and the ground layer, a first metal pattern 51 and a second metal pattern 52. And a fourth layer in which the ground layer 70 is disposed, and the first via is between the third layer and the fourth layer, and the second layer is formed. A via electrically connects between the first layer and the third layer. It is assumed that the second layer is made of a dielectric 60. That is, the printed circuit board 1 of the second embodiment is different from the printed circuit board 1 of the first embodiment in that the second metal pattern 52 is provided in the third layer together with the first metal pattern 51, and The second via 42 connects the second conductor 12 and the second metal pattern 52.

  Here, when the 1st connection conductor 21 and the 1st component 31 are arrange | positioned in the area of the 1st metal pattern 51, the electrostatic capacitance between the ground layers 70 in the connection point of the 1st connection conductor 21 is carried out. The capacitance depends on the area of the first connection conductor 21 and the first component 31 and the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51. Further, when the second component 32 is disposed within the area of the second metal pattern 52, the capacitance between the second connection conductor 22 and the ground layer 70 at the connection point of the second connection conductor 22 is the second metal pattern. 52 and the distance between the second metal pattern 52 and the ground layer 70.

  For example, as shown in FIG. 3, when the first connection conductor 21 is larger than the second connection conductor 22, the balance of the differential line deteriorates. However, in the second embodiment, the first connection conductor 21 is deteriorated. And the area of the first component 31, the distance between the first connection conductor 21 and the first component 31, and the first metal pattern 51, the area of the second metal pattern 52, and the second metal. The distance between the pattern 52 and the ground layer 70 is adjusted, and the capacitance (first capacitance) between the first connection conductor 21 and the first component 31 and the first metal pattern 51; By making the difference between the capacitance (second capacitance) between the second metal pattern 52 and the ground layer 70 within the design target range, the balance of the differential line is improved. At this time, adjusting the difference between the first capacity and the second capacity to be within the range of the design target includes adjusting the first capacity and the second capacity equally.

Hereinafter, each example for adjusting the difference between the first capacity and the second capacity in the second embodiment to be within the range of the design target will be described.
First, the area of the first metal pattern 51 is the same or larger than the total area of the first connection conductor 21 and the first component 31, and the area of the second metal pattern 52 is the second connection conductor 22. A case where the same or larger than the combined area of the second part 32 will be described.
The first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, and the second connection conductor 22 and the second component 32 are arranged in the area of the second metal pattern The first connection conductor 21 and the capacitance between the first component 31 and the first metal pattern 51 (first capacitance), the second metal pattern 52 and the ground layer 70 The balance of the differential line can be increased by adjusting so that the difference between the capacitance and the second capacitance is within the design target range.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the second metal pattern 52 and the distance between the second metal pattern 52 and the ground layer 70 can be mentioned.

  Next, the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, or the area of the second metal pattern 52 is the second connection conductor 22 and the second area. A case where the area is smaller than the total area of the parts 32 or a case where both are small will be described.

  If the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, all or part of at least one of the first connection conductor 21 and the first component 31. Is disposed outside the area of the first metal pattern 51 and the area of the second metal pattern 52 is smaller than the combined area of the second connection conductor 22 and the second component 32, the second connection All or part of at least one of the conductor 22 and the second component 32 may be disposed outside the area of the second metal pattern 52.

  For example, when at least a part of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, the portion between the portion disposed outside the area and the ground layer 70 is disposed. The capacitance generated in the first connection conductor 21 and the first component 31 and the first metal pattern 51 is generated in addition to the capacitance between the first connection conductor 21 and the first component 31. For example, when at least a part of the second connection conductor 22 and the second component 32 is disposed outside the area of the second metal pattern 52, the portion disposed outside the area, the ground layer 70, and the like. The capacitance generated between the second metal pattern 52 and the ground layer 70 is generated in addition to the capacitance between the second metal pattern 52 and the ground layer 70.

First, the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, and the area of the second metal pattern 52 is the second connection conductor 22 and the second connection pattern. A case where the area is smaller than the combined area of the parts 32 will be described.
A part of at least one of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, and at least one of the second connection conductor 22 and the second component 32. Is disposed outside the area of the second metal pattern 52, the portion of the first connection conductor 21 and the first component 31 disposed outside the area of the first metal pattern 51 and the ground layer 70. Between the first connecting conductor 21 and the first component 31 and the first metal pattern 51 (first capacitance), second capacitance The capacitance generated between the portion of the connecting conductor 22 and the second component 32 arranged outside the area of the second metal pattern 52 and the ground layer 70, and the second metal pattern 52 and the ground layer 70 Electrostatic between The amount of synthetic capacity that the difference between the (second volume) is adjusted to be within the design target, it is possible to increase the balance of the differential lines.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the portion of the first connection conductor 21 and the first component 31 arranged outside the area of the first metal pattern 51, and the distance between the portion arranged outside the area and the ground layer 70 The area of the second metal pattern 52, the distance between the second metal pattern 52 and the ground layer 70, and the area outside the second metal pattern 52 in the second connection conductor 22 and the second component 32. And the distance between the portion disposed outside the area and the ground layer 70.

  Next, the area of the first metal pattern 51 is the same as or larger than the total area of the first connection conductor 21 and the first component 31, while the area of the second metal pattern 52 is the second connection. A case where the area is smaller than the total area of the conductor 22 and the second component 32 will be described.

  The first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, and at least one part of the second connection conductor 22 and the second component 32 is the second. When arranged outside the area of the metal pattern 52, the capacitance between the first connection conductor 21 and the first component 31 and the first metal pattern 51 (first capacitance), and the second connection conductor 22. And a capacitance generated between a portion of the second component 32 arranged outside the area of the second metal pattern 52 and the ground layer 70, and a static electricity between the second metal pattern 52 and the ground layer 70. The balance of the differential line can be increased by adjusting the difference between the capacitance and the combined capacitance (second capacitance) to be within the design target range.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the second metal pattern 52, the distance between the second metal pattern 52 and the ground layer 70, and the area outside the second metal pattern 52 in the second connection conductor 22 and the second component 32. And the distance between the portion disposed outside the area and the ground layer 70.

  Next, the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, while the area of the second metal pattern 52 is the same as that of the second connection conductor 22. A case where the second component 32 is the same or larger than the combined area will be described.

  A part of at least one of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, and the second connection conductor 22 and the second component 32 are the second components. When arranged in the area of the metal pattern, the capacitance generated between the portion of the first connecting conductor 21 and the first component 31 arranged outside the area of the first metal pattern 51 and the ground layer 70. A combined capacitance (first capacitance) of capacitance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, a second metal pattern 52, and the ground layer 70. The balance of the differential line can be increased by adjusting so that the difference from the capacitance (second capacitance) is within the range of the design target.

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the portion of the first connection conductor 21 and the first component 31 arranged outside the area of the first metal pattern 51, and the distance between the portion arranged outside the area and the ground layer 70 The area of the second connection conductor 22 and the second metal pattern 52 and the distance between the second metal pattern 52 and the ground layer 70 can be mentioned.

  In addition, the 1st conductor 11 demonstrated so far, the 1st component 31 relevant to this, the 1st connection conductor 21, the 1st metal pattern 51, the 2nd conductor 12, and the 2nd relevant to this For the component 32, the second connection conductor 22, and the second metal pattern 52, for example, the interpretation of the arrangement of the first and second metal patterns 51 and 52, the connection destination of the metal pattern, the size relationship of the areas, etc. However, the balance of the differential line can be similarly increased by adjusting according to the condition contents.

  FIG. 5 is a partially enlarged view of a schematic plan view of a printed circuit board relating to the connection between the second conductor 12 and the second metal pattern 52 of the second embodiment. The shape of the metal pattern and the arrangement of vias will be described based on the drawings. First, FIG. 5A shows the second conductor 12, the second component 32, the second connection conductor 22, the second metal pattern 52, and the second via in the schematic plan view of the printed circuit board of FIG. 42 is a partially enlarged view of 42. FIG. Here, the second via 42 is arranged on the second conductor 12 so as to connect between the second conductor 12 of the first layer and the second metal pattern 52 of the third layer. . At this time, the second metal pattern 52 only needs to be arranged in a shape extending directly below the second via 42 in order to connect to the second conductor 12.

  Moreover, the modification of the shape of the 2nd metal pattern 52 and arrangement | positioning of the 2nd via | veer 42 is shown to FIG.5 (b) to (d). FIG. 5B is an example in which the shape of the second metal pattern 52 is changed without changing the arrangement of the second vias 42 from FIG. That is, in this example, the shape immediately below the second conductor 12 of the second metal pattern 52 is only the second via 42 portion. FIG. 5C shows an example in which the shape of the second metal pattern 52 is not changed and the arrangement of the second vias 42 is changed on the second connection conductor 22. FIG. 5D shows an example in which the shape of the second metal pattern 52 and the arrangement of the second vias 42 are both changed. In the case of FIG. 5D, the second metal pattern 52 only needs to be arranged in a shape extending directly below the second via 42 in order to connect to the second connection conductor 22. The shape of the second metal pattern 52 is not limited to a rectangle as shown in FIGS. 5A, 5C, and 5D, or a convex shape as shown in FIG. The shape may be cut obliquely or in a curved line, and the first layer of the second conductor 12 or the second connection conductor 22 and the third layer of the second metal pattern 52 are electrically connected via the second via 42. I just need to be able to connect to.

  Further, the relationship between the first conductor 11 and the first metal pattern 51 can also be considered in the same manner as in FIGS. In this case, however, the first via 41 connects the metal pattern 51 and the ground layer 70 instead of the position shown in FIG.

  In the second embodiment, a pair of the first component 31 and the second component 32, the first connection conductor 21 and the second conductor 12 with respect to the first conductor 11 and the second conductor 12 forming the differential line. The mounting of the two connection conductors 22, the first metal pattern 51, and the second metal pattern 52 has been described. There may be cases where multiple wirings or other parts are mounted on this printed circuit board, or connection conductors or parts may be mounted only on one side of the differential line. The overall balance can be increased by improving the balance.

  In the second embodiment, the printed circuit board having a four-layer structure has been described. However, the printed circuit board is not limited to the four layers and includes other layers not directly used in the mounting portion described here. It can also be applied to.

  Furthermore, in the above example, the first metal pattern 51 and the second metal pattern 52 are provided in the third layer, but the difference between the first capacitance and the second capacitance is within the design target range. However, these metal patterns may be provided in the second layer, and the first metal pattern 51 and the second metal pattern 52 may be provided in different layers.

  As described above, according to the printed circuit board of the second embodiment, the differential line composed of the first conductor and the second conductor formed in the layer on which the wiring and components are mounted, and the differential line sandwiched between A first component provided on the first conductor side, a second component provided on the second conductor side, a first connection conductor connecting the first component and the first conductor; A second connection conductor for connecting the second component and the second conductor, and a layer between the layer on which the wiring and the component are mounted and the ground layer, and the first connection conductor and the first component; Provided in the first metal pattern formed immediately below, the layer between the wiring and component mounting layer and the ground layer, and formed at the position directly below the second connection conductor and the second component. A second metal pattern, wherein the first metal pattern and the ground layer are electrically connected, and Since the second conductor or the second connection conductor and the second metal pattern are electrically connected to each other, the differential line is provided even when the additional circuit is mounted and the high-density mounting is performed. The degree of balance can be improved.

  According to the printed circuit board of the second embodiment, the first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are When arranged in the area of the second metal pattern, a first capacitance that is an electrostatic capacitance generated between the first connection conductor and the first component and the first metal pattern, and the second metal Since the difference between the second capacitance, which is the capacitance generated between the pattern and the ground layer, is set to a value within the setting range, the balance of the differential line is improved and the common on the differential line is increased. The mode noise can be suppressed, the radiation noise from the differential line can be suppressed, and the noise resistance of the differential line can be improved.

  Further, according to the printed circuit board of the second embodiment, at least a part of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second When at least a part of the connection conductor and the second component is disposed outside the area of the second metal pattern, the first metal pattern of the first connection conductor and the first component And a capacitance generated between the portion arranged outside the area and the ground layer, and a capacitance generated between the first connection conductor and the first component and the first metal pattern. A first capacitance, a capacitance generated between a portion of the second connection conductor and the second component arranged outside the area of the second metal pattern and the ground layer, and a second metal Synthesis with capacitance generated between pattern and ground layer Since the difference in the second capacitance, which is the quantity, is set to a value within the setting range, the balance of the differential line is improved, the common mode noise on the differential line is suppressed, and the radiation from the differential line is reduced. In addition to suppressing noise, the noise resistance of the differential line can be improved.

  Further, according to the printed circuit board of the second embodiment, the first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are Among these, when at least a part of any one of them is arranged outside the area of the second metal pattern, the first capacitance that is generated between the first connection conductor and the first component and the first metal pattern. 1, a capacitance generated between a portion of the second connection conductor and the second component arranged outside the area of the second metal pattern and the ground layer, and the second metal pattern, The difference between the second capacitance, which is the combined capacitance with the capacitance generated between the ground layer and the ground layer, is set to a value within the setting range. Common mode noise is suppressed, and radiation noise from differential lines is suppressed Rutotomoni, it is possible to improve the noise resistance of the differential lines.

  Further, according to the printed circuit board of the second embodiment, at least a part of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second When the connecting conductor and the second component are arranged in the area of the second metal pattern, the portion of the first connecting conductor and the first component arranged outside the area of the first metal pattern; A first capacitance which is a combined capacitance of the capacitance generated between the ground layer and the capacitance generated between the first connection conductor and first component and the first metal pattern; The difference between the second capacitance, which is the capacitance generated between the metal pattern and the ground layer, is set to a value within the setting range, so that the balance of the differential line is improved, Common mode noise is suppressed, and radiation noise from differential lines is suppressed Rutotomoni, it is possible to improve the noise resistance of the differential lines.

Embodiment 3 FIG.
6 and 7 are configuration diagrams showing an example of a printed circuit board according to Embodiment 3 of the present invention, FIG. 6 is a schematic plan view of the printed circuit board, and FIG. 7 is a cross-sectional view taken along the line CC in FIG. FIG.
In these drawings, the printed circuit board 1 has a layer for mounting wiring and components and a ground layer. The first conductor 11 and the second conductor 12 form a differential line formed in a layer for mounting wiring and components. The first component 31 and the second component 32 are placed at positions close to each other across the differential line. The first connection conductor 21 connects the first component 31 and the first conductor 11. The second connection conductor 22 connects the second component 32 and the second conductor 12. The first metal pattern 51 is a layer between the layer and the ground layer that implements the wiring and parts, and is formed at a position immediately below the first connection conductor 21 and the first part 31. The second metal pattern 52 is formed in a layer different from the layer in which the first metal pattern 51 is formed with the ground layer 70 interposed therebetween. The first via 41 electrically connects the first metal pattern 51 and the ground layer 70. The second via 42 electrically connects the second conductor 12 and the second metal pattern 52.

  Thus, the printed circuit board 1 includes the first conductor 11, the second conductor 12, the first component 31, the second component 32, the first connection conductor 21, and the first conductor 11 as layers for mounting wiring and components. A first layer in which the two connection conductors 22 are disposed, a second layer in which the first metal pattern 51 is formed, a third layer in which the ground layer 70 is disposed, and a second metal pattern 52. The first via 41 is formed between the second layer and the third layer, and the second via 42 is formed between the first layer and the fourth layer. Electrical connection between layers. At this time, the second via 42 is prevented from being in electrical contact with the ground layer 70.

  Here, when the 1st connection conductor 21 and the 1st component 31 are arrange | positioned in the area of the 1st metal pattern 51, the electrostatic capacitance between the ground layers 70 in the connection point of the 1st connection conductor 21 is carried out. The capacitance depends on the areas of the first connection conductor 21 and the first component 31 and the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51.

  The capacitance between the second connection conductor 22 and the ground layer 70 at the connection point is equal to the capacitance between the second connection conductor 22 and the second component 32 and the ground layer 70, and the second capacitance. The resultant capacitance is a capacitance between the metal pattern 52 and the ground layer 70. At this time, the capacitance between the second connection conductor 22 and the second component 32 and the ground layer 70 is the same as the area of the second connection conductor 22 and the second component 32 and the second connection conductor 22. And depending on the distance between the second part 32 and the ground layer 70. Further, the capacitance between the second metal pattern 52 and the ground layer 70 depends on the area of the second metal pattern 52 and the distance between the second metal pattern 52 and the ground layer 70.

  For example, as shown in FIG. 6, when the first connection conductor 21 is larger than the second connection conductor 22, the balance of the differential line deteriorates, but in the third embodiment, the first connection conductor 21 is deteriorated. And the area of the first component, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, the area of the second connection conductor 22 and the second component 32, and The distance between the second connection conductor 22 and the second component 32 and the ground layer 70, the area of the second metal pattern 52, and the distance between the second metal pattern 52 and the ground layer 70 The first connection conductor 21 and the capacitance between the first component 31 and the first metal pattern 51 (first capacitance), and the second connection conductor 22 and the second component 32 are adjusted. Between the first metal pattern 52 and the ground layer 7. Combined capacitance of the capacitance between the in be in the range of the design goals of the difference (second capacitor), thereby improving the balance of the differential lines. At this time, adjusting the difference between the first capacity and the second capacity to be within the range of the design target includes adjusting the first capacity and the second capacity equally. By such adjustment, the balance of the differential line can be increased.

Hereinafter, each example for adjusting the difference between the first capacity and the second capacity in the third embodiment to be within the range of the design target will be described.
First, the case where the area of the first metal pattern 51 is the same or larger than the total area of the first connection conductor 21 and the first component 31 will be described.
When the first connection conductor 21 and the first component 31 are arranged in the area of the first metal pattern 51, the first connection conductor 21 and the first component 31 and the first metal pattern 51 are between them. Between the second connection conductor 22 and the second component 32 and the ground layer 70, the second metal pattern 52, and the ground layer 70. The balance of the differential line can be increased by adjusting the difference between the capacitance generated in the middle and the combined capacitance (second capacitance) to be within the design target range.

  At this time, as the objects of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component and the first metal pattern 51, The area of the second connection conductor 22 and the second component 32, the distance between the second connection conductor 22 and the second component 32 and the ground layer 70, the area of the second metal pattern 52, and the second The distance between the metal pattern 52 and the ground layer 70 is mentioned.

Next, a case where the area of the first metal pattern 51 is smaller than the total area of the first connection conductor 21 and the first component 31 will be described.
If the area of the first metal pattern 51 is smaller than the combined area of the first connection conductor 21 and the first component 31, all or part of at least one of the first connection conductor 21 and the first component 31. May be disposed outside the area of the first metal pattern 51.
For example, when at least a part of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, the portion between the portion disposed outside the area and the ground layer 70 is disposed. Is generated in addition to the capacitance between the first connecting conductor 21 and the first component 31 and the first metal pattern 51.

  When at least one part of the first connection conductor 21 and the first component 31 is disposed outside the area of the first metal pattern 51, the first connection conductor 21 and the first component 31 Capacitance generated between the portion disposed outside the area of the first metal pattern 51 and the ground layer 70, and between the first connection conductor 21 and the first component 31 and the first metal pattern 51. And the capacitance generated between the second connection conductor 22 and the second component 32 and the ground layer 70, the second metal pattern 52, and the ground. The balance of the differential line can be increased by adjusting the difference between the capacitance generated between the layer 70 and the combined capacitance (second capacitance) within the design target range. .

  At this time, as an object of adjustment, the area of the first connection conductor 21 and the first component 31, the distance between the first connection conductor 21 and the first component 31 and the first metal pattern 51, and The area of the portion of the first connection conductor 21 and the first component 31 that is disposed outside the area of the first metal pattern 51, the distance between the portion disposed outside the area and the ground layer 70, The area of the second connection conductor 22 and the second component 32, the distance between the second connection conductor 22 and the second component 32 and the ground layer 70, the area of the second metal pattern 52, The distance between the two metal patterns 52 and the ground layer 70 is mentioned.

  In addition, the 1st conductor 11 demonstrated so far, the 1st component 31 relevant to this, the 1st connection conductor 21, the 1st metal pattern 51, the 2nd conductor 12, and the 2nd relevant to this For the component 32, the second connection conductor 22, and the second metal pattern 52, for example, even if the interpretation of the relationship between the arrangement of the first and second metal patterns 51 and 52 and the size of the area is reversed, the condition contents Similarly, the balance of the differential line can be increased.

  The shape of the first metal pattern 51 in the third embodiment can also be described in the same manner as the shape of the metal pattern in the second embodiment shown in FIG. In this case, however, the first via 41 connects the metal pattern 51 and the ground layer 70 instead of the position shown in FIG.

  In the third embodiment, with respect to the first conductor 11 and the second conductor 12 forming the differential line, a pair of the first component 31 and the second component 32, the first connection conductor 21 and the second conductor The mounting of the connection conductor 22, the first metal pattern 51, and the second metal pattern 52 has been described. There may be cases where multiple wirings or other parts are mounted on this printed circuit board, or connection conductors or parts may be mounted only on one side of the differential line. The overall balance can be increased by improving the balance.

  In the third embodiment, the mounting is described for a printed circuit board having a four-layer structure. However, the printed circuit board is not limited to four layers, and includes other layers not directly used in the mounting portion described here. It can also be applied to.

  As described above, according to the printed circuit board of the third embodiment, the differential line composed of the first conductor and the second conductor formed on the layer on which the wiring and components are mounted, and the differential line sandwiched between them. A first component provided on the first conductor side, a second component provided on the second conductor side, a first connection conductor connecting the first component and the first conductor; A second connection conductor for connecting the second component and the second conductor, and a layer between the layer on which the wiring and the component are mounted and the ground layer, and the first connection conductor and the first component; The first metal pattern formed immediately below and the first metal pattern sandwiched between the first metal pattern and the ground metal layer are formed at a position immediately below the second connection conductor and the second component. A second metal pattern, wherein the first metal pattern and the ground layer are electrically connected, and Since the second conductor or the second connection conductor and the second metal pattern are electrically connected, even if the additional circuit is mounted and the high-density mounting is performed, the difference The balance of the flow line can be improved.

Embodiment 4 FIG.
8 and 9 is a configuration diagram showing an example of a printed circuit board according to the fourth embodiment of the present invention, FIG 8 is a schematic plan view of a printed circuit board, D-D line in FIG. 9 8 It is sectional drawing.
In these drawings, the printed circuit board 1 has a layer for mounting wiring and components and a ground layer. The first conductor 11 and the second conductor 12 form a differential line formed in a layer for mounting wiring and components. The first component 31 and the second component 32 are placed at positions close to each other across the differential line. The first connection conductor 21 connects the first component 31 and the first conductor 11. The second connection conductor 22 connects the second component 32 and the second conductor 12. The first dielectric 61 of the dielectric constant ε1 between the first connection conductor 21 and the first component 31 and the ground layer 70, between the second connection conductor 22 and the second part 32 and the ground layer 70 Includes a second dielectric 62 having a dielectric constant ε2.

  Here, the capacitance between the first connection conductor 21 and the ground layer 70 depends on the area of the first connection conductor 21 and the first component 31 and the dielectric constant ε1 of the first dielectric 61. To do. Similarly, the capacitance between the second connection conductor 22 and the ground layer 70 depends on the area of the second connection conductor 22 and the second component 32 and the dielectric constant ε2 of the second dielectric 62. To do.

  For example, as shown in FIG. 8, when the first connection conductor 21 is larger than the second connection conductor 22, the balance of the differential line deteriorates. However, in the fourth embodiment, the first dielectric 61 is used. The dielectric constant ε1 of the second dielectric 62 and the dielectric constant ε2 of the second dielectric 62 are adjusted so that the capacitance between the first connection conductor 21 and the first component 31 and the ground layer 70 (first capacitance) By making the difference in capacitance (second capacitance) between the second connection conductor 22 and the second component and the ground layer 70 within the design target range, the balance of the differential line is improved. ing.

  In addition, the 1st conductor 11 demonstrated so far, the 1st component 31 relevant to this, the 1st connection conductor 21, the 1st metal pattern 51, the 2nd conductor 12, and the 2nd relevant to this For the part 32, the second connection conductor 22, and the second metal pattern 52, for example, even if the interpretation of the size relationship of the areas of the first and second connection conductors 21 and 22 is reversed, it corresponds to the condition contents Thus, the balance of the differential line can be increased similarly.

  In the fourth embodiment, with respect to the first conductor 11 and the second conductor 12 forming the differential line, a pair of the first component 31 and the second component 32, the first connection conductor 21 and the second conductor The mounting of the connection conductor 22 has been described. There may be cases where multiple wirings or other parts are mounted on this printed circuit board, or connection conductors or parts may be mounted only on one side of the differential line. The overall balance can be increased by improving the balance.

  In the fourth embodiment, the mounting is described for the printed circuit board having a two-layer structure having a smaller number of layers than in the first to third embodiments. However, the mounting is not limited to the two layers, and the mounting portion described here directly The present invention can also be applied to a printed circuit board having a multilayer structure including other layers not used.

  As described above, according to the printed circuit board of the fourth embodiment, the differential line composed of the first conductor and the second conductor formed on the wiring and component mounting layers, and the differential line sandwiched between them. A first component provided on the first conductor side, a second component provided on the second conductor side, a first connection conductor connecting the first component and the first conductor; A second connecting conductor connecting the second component and the second conductor; a first dielectric provided between the first connecting conductor and the first component and the ground layer; A connection conductor and a second dielectric provided between the second component and the ground layer; a capacitance generated between the first component and the ground layer; and the first connection conductor and the ground. A first capacitance which is a combined capacitance with a capacitance generated between the second layer and a capacitance generated between the second component and the ground layer And the difference between the second capacitance, which is the combined capacitance of the capacitance generated between the second connection conductor and the ground layer, is set to a value within the set range, so that the balance of the differential line Thus, common mode noise on the differential line can be suppressed, radiation noise from the differential line can be suppressed, and noise resistance of the differential line can be improved.

Embodiment 5 FIG.
10 and 11 are configuration diagrams showing an example of a printed circuit board according to Embodiment 5 of the present invention. FIG. 10 is a schematic plan view of the printed circuit board. FIG. 11 is a line EE in FIG. It is sectional drawing.
In these drawings, the printed circuit board 1 has a layer for mounting wiring and components and a ground layer. The first conductor 11 and the second conductor 12 form a differential line formed in a layer for mounting wiring and components. The first component 31 and the second component 32 are placed at positions close to each other across the differential line. The first connection conductor 21 connects the first component 31 and the first conductor 11. The second connection conductor 22 connects the second component 32 and the second conductor 12. The third conductor 80 is connected to the second conductor 12. It is assumed that there is a dielectric 60 between the wiring and component mounting layers and the ground layer.

  Here, the capacitance between the first connection conductor 21 and the ground layer 70 depends on the areas of the first connection conductor 21 and the first component 31. The capacitance between the second connection conductor 22 and the third conductor 80 and the ground layer 70 is equal to the capacitance between the second connection conductor 22 and the second component 32 and the ground layer 70. And the combined capacitance of the capacitance between the third conductor 80 and the ground layer 70. At this time, the capacitances of the second connection conductor 22 and the third conductor 80 and the ground layer 70 depend on the areas of the second connection conductor 22 and the second component 32 and the area of the third conductor 80. .

  For example, as shown in FIG. 10, when the first connection conductor 21 is larger than the second connection conductor 22, the balance of the differential line deteriorates. However, in the fifth embodiment, the first connection conductor 21 is deteriorated. And the area of the 1st component 31, the area of the 2nd connection conductor 22 and the 2nd component 32, and the area of the 3rd conductor 80 are adjusted, and the 1st connection conductor 21 and the 1st component 31 are adjusted. Between the second connection conductor 22 and the second part 32 and the ground layer 70, and a third conductor 80. By making the difference of the combined capacitance (second capacitance) of the capacitance with the ground layer 70 within the range of the design target, the balance of the differential line is improved.

  In addition, the 1st conductor 11 demonstrated so far, the 1st component 31 and the 1st connection conductor 21 relevant to this, the 2nd conductor 12, the 2nd component 32 related to this, and the 2nd For the connection conductor 22, for example, even if the interpretation of the size relationship of the areas of the first and second connection conductors 21, 22 and the connection destination of the third conductor 80 is reversed, the connection conductor 22 should be adjusted according to the condition contents. Similarly, the balance of the differential line can be increased.

  In the fifth embodiment, with respect to the first conductor 11 and the second conductor 12 forming the differential line, the pair of the first component 31 and the second component 32, the first connection conductor 21 and the second conductor The mounting of the connection conductor 22 has been described. There may be cases where multiple wirings or other parts are mounted on this printed circuit board, or connection conductors or parts may be mounted only on one side of the differential line. The overall balance can be increased by improving the balance.

  In the fifth embodiment, the mounting is described for the printed circuit board having a two-layer structure having a smaller number of layers than in the first to third embodiments. However, the mounting is not limited to the two layers, and the mounting portion described here is directly used. The present invention can also be applied to a printed circuit board having a multilayer structure including other layers not used.

  As described above, according to the printed circuit board of the fifth embodiment, the differential line composed of the first conductor and the second conductor formed on the wiring and component mounting layers, and the differential line sandwiched between them. A first component provided on the first conductor side, a second component provided on the second conductor side, a first connection conductor connecting the first component and the first conductor; A capacitance generated between the first component and the ground layer, the second connection conductor connecting the second component and the second conductor, and a third conductor connected to the second conductor A first capacitance that is a combined capacitance of the first connection conductor and the capacitance generated between the first connection conductor and the ground layer, a capacitance generated between the second component and the ground layer, and a second capacitance The combined capacitance of the capacitance generated between the connection conductor and the ground layer and the capacitance generated between the third conductor and the ground layer Since the difference from the second capacitance is set to a value within the setting range, the balance of the differential line is improved, the common mode noise on the differential line is suppressed, and the radiation noise from the differential line is reduced. And the noise resistance of the differential line can be improved.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  11 1st conductor, 12 2nd conductor, 21 1st connection conductor, 22 2nd connection conductor, 31 1st component, 32 2nd component, 41 1st via, 42 2nd via, 51 1st metal pattern, 52 2nd metal pattern, 60 dielectric, 61 1st dielectric, 62 2nd dielectric, 70 ground layer, 80 3rd conductor.

Claims (13)

A differential line composed of a first conductor and a second conductor formed in a layer for mounting wiring and components;
A first component provided on the first conductor side and a second component provided on the second conductor side across the differential line;
A first connection conductor connecting the first component and the first conductor;
A second connection conductor connecting the second component and the second conductor;
A first metal pattern provided in a layer between a layer on which the wiring and the component are mounted and a ground layer, and formed at a position immediately below the first connection conductor and the first component;
A second metal pattern provided in a layer between the wiring and component mounting layer and the ground layer, and formed at a position immediately below the second connection conductor and the second component;
The printed circuit board, wherein the first metal pattern and the second metal pattern are electrically connected to the ground layer, respectively. The first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are in the area of the second metal pattern. If placed in
A first capacitance which is a capacitance generated between the first connection conductor and the first component and the first metal pattern; the second connection conductor and the second component; The printed circuit board according to claim 1, wherein a difference from a second capacitance, which is a capacitance generated between the two metal patterns, is set to a value within a set range. At least a part of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second connection conductor and the second component Among them, when at least a part of any one is disposed outside the area of the second metal pattern,
Of the first connection conductor and the first component, a capacitance generated between a portion of the first metal pattern disposed outside the area of the first metal pattern and the ground layer, and the first connection conductor and Of the first capacitance, which is a combined capacitance of the capacitance generated between the first component and the first metal pattern, the second connection conductor and the second component, the second capacitance Capacitance generated between the portion of the metal pattern outside the area and the ground layer, and static electricity generated between the second connection conductor and the second component, and the second metal pattern. The printed circuit board according to claim 1, wherein a difference between the second capacity, which is a combined capacity with the electric capacity, is set to a value within a set range. The first connection conductor and the first component are arranged in an area of the first metal pattern, and at least a part of the second connection conductor and the second component is When disposed outside the area of the second metal pattern,
Among the first connection conductor and the first component that is an electrostatic capacitance generated between the first component and the first metal pattern, the second connection conductor and the second component, Capacitance generated between the portion disposed outside the area of the second metal pattern and the ground layer, and between the second connection conductor and the second component and the second metal pattern. The printed circuit board according to claim 1, wherein a difference between the second capacitance, which is a combined capacitance with the capacitance generated in the step, is set to a value within a set range. A differential line composed of a first conductor and a second conductor formed in a layer for mounting wiring and components;
A first component provided on the first conductor side and a second component provided on the second conductor side across the differential line;
A first connection conductor connecting the first component and the first conductor;
A second connection conductor connecting the second component and the second conductor;
A first metal pattern provided in a layer between a layer on which the wiring and the component are mounted and a ground layer, and formed at a position immediately below the first connection conductor and the first component;
A second metal pattern provided in a layer between the wiring and component mounting layer and the ground layer, and formed at a position immediately below the second connection conductor and the second component;
The first metal pattern and the ground layer are electrically connected, and the second conductor or the second connection conductor and the second metal pattern are electrically connected. Printed circuit board. The first connection conductor and the first component are arranged in the area of the first metal pattern, and the second connection conductor and the second component are in the area of the second metal pattern. If placed in
A first capacitance, which is a capacitance generated between the first connection conductor and the first component, and the first metal pattern, and generated between the second metal pattern and the ground layer. 6. The printed circuit board according to claim 5, wherein a difference from the second capacitance which is an electrostatic capacitance is set to a value within a setting range. At least a part of the first connection conductor and the first component is disposed outside the area of the first metal pattern, and the second connection conductor and the second component Among them, when at least a part of any one is disposed outside the area of the second metal pattern,
Of the first connection conductor and the first component, a capacitance generated between a portion of the first metal pattern disposed outside the area of the first metal pattern and the ground layer, and the first connection conductor and Of the first capacitance, which is a combined capacitance of the capacitance generated between the first component and the first metal pattern, the second connection conductor and the second component, the second capacitance A capacitance generated between the portion disposed outside the area of the metal pattern and the ground layer and a capacitance generated between the second metal pattern and the ground layer. 6. The printed circuit board according to claim 5, wherein a difference between the two capacitances is set to a value within a set range. The first connection conductor and the first component are arranged in an area of the first metal pattern, and at least a part of the second connection conductor and the second component is When disposed outside the area of the second metal pattern,
Among the first connection conductor and the first component that is an electrostatic capacitance generated between the first component and the first metal pattern, the second connection conductor and the second component, A combined capacitance of a capacitance generated between a portion disposed outside the area of the second metal pattern and the ground layer and a capacitance generated between the second metal pattern and the ground layer. 6. The printed circuit board according to claim 5, wherein a difference from the second capacitance is a value within a setting range.   The said 1st metal pattern and the said 2nd metal pattern are formed in the same layer, Any one of the Claims 1-4 and Claims 5-8 characterized by the above-mentioned. Printed circuit board.   9. The method according to claim 1, wherein the first metal pattern and the second metal pattern are formed in different layers. 10. Printed circuit board. A differential line composed of a first conductor and a second conductor formed in a layer for mounting wiring and components;
A first component provided on the first conductor side and a second component provided on the second conductor side across the differential line;
A first connection conductor connecting the first component and the first conductor;
A second connection conductor connecting the second component and the second conductor;
A first metal pattern provided in a layer between a layer on which the wiring and the component are mounted and a ground layer, and formed at a position immediately below the first connection conductor and the first component;
A second metal pattern provided in a layer different from the first metal pattern across the ground layer, and formed at a position immediately below the second connection conductor and the second component;
The first metal pattern and the ground layer are electrically connected, and the second conductor or the second connection conductor and the second metal pattern are electrically connected. Printed circuit board. A differential line composed of a first conductor and a second conductor formed in a layer for mounting wiring and components;
A first component provided on the first conductor side and a second component provided on the second conductor side across the differential line;
A first connection conductor connecting the first component and the first conductor;
A second connection conductor connecting the second component and the second conductor;
A first dielectric provided between the first connecting conductor and the first component and a ground layer;
A second dielectric provided between the second connection conductor and the second component and a ground layer;
A first capacitance that is a combined capacitance of a capacitance generated between the first component and the ground layer and a capacitance generated between the first connection conductor and the ground layer; A difference between a second capacitance that is a combined capacitance of a capacitance generated between the second component and the ground layer and a capacitance generated between the second connection conductor and the ground layer is calculated. A printed circuit board having a value within a set range. A differential line composed of a first conductor and a second conductor formed in a layer for mounting wiring and components;
A first component provided on the first conductor side and a second component provided on the second conductor side across the differential line;
A first connection conductor connecting the first component and the first conductor;
A second connection conductor connecting the second component and the second conductor;
A third conductor connected to the second conductor;
A first capacitance that is a combined capacitance of a capacitance generated between the first component and the ground layer and a capacitance generated between the first connection conductor and the ground layer; Capacitance between the second component and the ground layer, capacitance between the second connection conductor and the ground layer, and between the third conductor and the ground layer. A printed circuit board characterized in that a difference between a generated capacitance and a second capacitance, which is a combined capacitance, is a value within a set range.

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