JPH07249843A - Multilayer printed wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the effect of noise on the analog signal system without using a shield member, to achieve high density and cost reduction. [Structure] The analog pattern 4 is formed on the second insulating layer 2B,
At least the power supply pattern or the GND pattern 5 is wired, and the analog pattern 4 is shielded by this power supply or the GND pattern 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board, and more particularly to a wiring design of a multilayer printed wiring board which has an analog pattern and is less susceptible to noise.

[0002]

2. Description of the Related Art Since an analog signal system is very susceptible to noise, when designing the wiring of a printed wiring board,
Usually, wiring is performed as shown in FIG. 4 or FIG. That is, FIG. 4 shows a printed wiring board 1 having a single insulating layer, and an analog pattern 4 is formed on one surface 3 of the insulating layer 2.
And, a power supply system or GND system pattern 5 in which the potential does not change abruptly is wired, and the analog pattern 4 is sandwiched between the power supply system or GND system pattern 5 for shielding. FIG. 5 shows a multilayer printed wiring board 6 having two insulating layers, and an analog pattern 4 and a power supply or GND pattern 5 on a surface 3 of the first insulating layer 2A opposite to the second insulating layer 2B. And the analog pattern 4 is shielded by this power supply system or GND system pattern 5, and the surface of the second insulation layer 2B opposite to the first insulation layer 2A is a solid pattern 8 of power supply system or GND system. By shielding with, it is made less susceptible to noise. In addition, a shield member is provided for noise generated from other printed wiring boards and an external noise source to prevent noise from jumping in.

[0003]

However, the method of shielding an analog pattern by using a shield member requires a large space, and therefore cannot be used for high density. Therefore, recently, high density is required. By reducing the number of shield members as the number of products increases, the mounting space for printed wiring boards is secured. Along with this, there has been a problem that the influence of noise generated from other printed wiring boards and external noise sources on the analog signal system increases.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to reduce the influence of noise on an analog signal system without using a shield member, and It is an object of the present invention to provide a multilayer printed wiring board capable of achieving higher density and lower cost.

[0005]

In order to achieve the above object, the multilayer printed wiring board according to claim 1 is a multilayer printed wiring board having at least two layers, in which an analog pattern is provided in an inner layer and at least a power supply pattern or G.
The ND pattern is wired. A multilayer printed wiring board according to a second aspect of the present invention is the multilayer printed wiring board according to the first aspect, wherein the analog pattern is shielded by the power supply or the GND pattern. The multilayer printed wiring board according to claim 3, wherein in the multilayer printed wiring board having at least three layers, an analog pattern and at least a power supply pattern or a GND pattern are wired in an inner layer, and the analog pattern is the power supply pattern or the GND pattern. A power supply or GND that shields and further shields the analog pattern on upper and lower layers adjacent to the inner layer
It is characterized in that a pattern is formed.

[0006]

In the present invention, since the analog pattern and the power supply pattern or the GND pattern are wired in the inner layer of the multilayer printed wiring board, the analog signal system can be easily sandwiched and shielded by the power supply system or the GND system pattern. it can. Therefore, the influence of external noise on the analog pattern can be reduced, and the shield member can be reduced.
Further, by forming a power supply or GND pattern on the upper and lower layers adjacent to the inner layer and sealing the analog pattern of the inner layer by these patterns, the influence of external noise can be further reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is an exploded perspective view showing an embodiment in which the present invention is applied to a three-layer printed wiring board, and FIG. 2 is a sectional view of the wiring board. In the figure, the same components as those in FIGS. 4 and 5 are designated by the same reference numerals. In these figures, this embodiment shows three insulating layers 2A, 2
In the multilayer printed wiring board 10 having B and 2C, the analog pattern 4 and the analog or digital power supply or G on the wiring surface 11 of the second insulating layer 2B which is the inner layer.
Wire the ND pattern 5 and use this power supply pattern or GN
The analog pattern 4 is sandwiched between the D patterns 5 so as to be shielded. As the power supply or GND pattern 5, a buck-boost power supply pattern or GND
The D pattern is also included. In addition, 12 and 13 are the first and third
Is the wiring surface of the insulating layers 2A and 2C.

Thus, in the multilayer printed wiring board 10 having such a structure, the analog pattern 4 and the power supply pattern or the GND pattern 5 are formed in the inner layer, and the analog pattern 4 is formed by the power supply pattern or the GND pattern 5.
Are shielded, it is less susceptible to noise on the multilayer printed wiring board 10 and noise from other printed wiring boards or external noise sources, and the shield member can be omitted. Therefore, the multilayer printed wiring board 10
Can be closely arranged together with other printed wiring boards, and high density can be achieved. Further, since no shield member is required, cost can be reduced.

FIG. 3 is an exploded perspective view showing another embodiment of the present invention. This embodiment is similar to the above embodiment, in the printed wiring board 10 consisting of three layers, the analog pattern 4 and the analog or digital power supply or the GND pattern 5 are provided on the wiring surface 11 of the second insulating layer 2B which is the inner layer. Wire and shield the analog pattern 4 by sandwiching it with this power supply pattern or GND pattern 5.
A power supply pattern or a GND pattern 5 ′ is wired on the wiring surfaces 14 and 15 of the first and third insulating layers 2A and 2C, and the analog pattern 4 is further shielded by these patterns 5 ′. The wiring surfaces 14 and 15 of the first and third insulating layers 2A and 2C are the same as the second insulating layer 2B.
And the opposite side. In such a configuration,
Compared with the above-mentioned embodiment, there is an advantage that the influence of noise due to another printed wiring board or an external noise source can be further reduced and prevented.

Although the above embodiments have been described for the case of being applied to a printed wiring board having three layers, the present invention is not limited to this and may have two layers. Of course, it may be more than one layer.

[0011]

As described above, in the multilayer printed wiring board according to the present invention, in at least two layers of the multilayer printed wiring board, the analog pattern and at least the power supply pattern or the GND pattern are wired in the inner layer. Alternatively, it is easy to sandwich the analog pattern with the GND pattern, and the influence of noise on the multilayer printed wiring board and noise from other printed wiring boards or external noise sources can be reduced. Therefore, the shield member can be omitted, the cost can be reduced, and the multilayer printed wiring board can be disposed in close contact with other printed wiring boards and the like, and high density can be achieved. The invention also provides at least 3
In a multilayer printed wiring board having more than one layer, an analog pattern and at least a power supply pattern or a GND pattern for shielding the analog pattern are wired in the inner layer, and a power supply or GND for shielding the analog pattern in upper and lower layers adjacent to the inner layer. Since the patterns are wired, it is possible to further reduce the influence of noise on the multilayer printed wiring board and noise from other printed wiring boards or external noise sources.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment in which the present invention is applied to a three-layer printed wiring board.

FIG. 2 is a sectional view of the wiring board.

FIG. 3 is an exploded perspective view showing another embodiment of the present invention.

FIG. 4 is a perspective view showing a conventional example of a printed wiring board.

FIG. 5 is an exploded perspective view showing a conventional example of a multilayer printed wiring board.

[Explanation of symbols]

2 ... Insulating layer, 2A ... 1st insulating layer, 2B ... 2nd insulating layer, 2C ... 3rd insulating layer, 4 ... Analog pattern, 5 ...
Power or DNG pattern.

Claims (3)

[Claims] 1. A multilayer printed wiring board having at least two layers, wherein an analog pattern and at least a power supply pattern or a GND pattern are wired in an inner layer. 2. The multilayer printed wiring board according to claim 1, wherein the analog pattern is shielded by the power supply or the GND pattern. 3. A multilayer printed wiring board having at least three layers, wherein an analog pattern and at least a power supply pattern or a GND pattern are wired in an inner layer, and the analog pattern is shielded by the power supply pattern or the GND pattern,
A multilayer printed wiring board, wherein a power source or a GND pattern for further shielding the analog pattern is formed on upper and lower layers adjacent to the inner layer.