JP2646710B2 - SOP type SMD double-sided printed board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a printed circuit board on which both sides of an SOP type SMD are mounted, and aims to provide a double sided mounted board of an SOP type SMD which improves a signal wiring density and increases a degree of freedom of a through hole position. In order to mount SOP type SMD on both sides of the printed board, SO
P-type SMD footprints are provided at overlapping positions on the front and back, through holes are provided at corresponding predetermined positions on both sides near the row of footprints, and terminal rows including power supply terminals overlap on the front and back. It is configured to mount SOP type SMD in the direction.

[Industrial applications]

The present invention relates to a printed board on which both sides of an SOP type SMD are mounted.

For electronic components used in electronic devices, semiconductor components and other components are also becoming smaller and more sophisticated, and mounting on printed circuit boards has been replaced by insertion-type components that use conventional terminal leads. Surface-mount components (hereinafter referred to as SMDs), in which leads are eliminated and the outer surface is configured as a terminal surface, are becoming mainstream.

The printed circuit board that constitutes the circuit is a multilayer wiring that connects layers between layers with through holes and thinning of the wiring to support high-density mounting, while the appearance of SMD adopts a double-sided mounting method that mounts components on both front and back sides It has come to be.

[Conventional technology]

 FIG. 2 shows a mounting diagram of a conventional double-sided mounting.

As an example of the related art, four SOP type SMDs 2 of the same shape, in which terminals are arranged in two rows of five terminals, each having the power supply terminal 5 and the ground terminal 7 at the same diagonal position, two on each of the front and back surfaces The state in which the components are closely mounted will be described as shown in FIG.

In the figure, the state on the front side is indicated by a solid line, and the state on the back side seen through from the front side is indicated by a dotted line.

That is, it is difficult to provide the through hole 4 at the position of the footprint 3 for connection of the SOP type SMD 2, and therefore, the through hole 4 must be provided at a position off the footprint 3.

In addition, the printed board 15 with the multilayer wiring, to shield between the wiring on the front side and the back side, and to arrange the connection parts and through holes of the components on the front and back without any restrictions, The power supply wiring and the ground wiring are provided in the intermediate layer. For connection to the SOP type SMD 2, through holes 4 are provided near the power supply terminals 5 and the ground terminal 7, respectively, and connected to the intermediate layer.

Further, through-holes 4 are provided at necessary places for connection of other circuits, and are used for connection between wiring layers.

[Problems to be solved by the invention]

However, the general through hole 4 must be provided at a position avoiding both or one of the surface mount SMD2 footprint 3 and the rear surface mount SMD2 footprint 3.
Be restricted.

For power supply connection and ground connection, at least two through holes 4 are required for each SMD 2.

Alternatively, providing a lead line at random from the footprint 3 and commonly using the through hole 4 may affect the signal circuit between the SMDs 2 and may hinder the high density of the signal circuit wiring. is there.

And so on.

The present invention has been made in view of the above problems, and has been made in view of the above problems.
The purpose is to provide double-sided mounting.

[Means for solving the problem]

As shown in FIG. 1, when mounting the SOP type SMD 2 on both the front and back surfaces of the printed board 1, as shown in FIG. Footprint 3
The terminal rows 6 including the power supply terminals 5 are provided at corresponding predetermined positions on both sides near the row of
The problem is solved by the double-sided mounting board of the SOP type SMD of the present invention in which the P type SMD 2 is mounted.

(Operation)

That is, since the footprint positions of the SMDs are overlapped on the front and back surfaces, the degree of freedom of the through-holes is increased, and the power supply terminals are arranged in the same terminal row, so that the through-holes can be shared.

In the SOP type SMD 2 having the same shape and having the power supply terminal 5 and the ground terminal 7 at diagonal positions, the positions of the footprints 3 in the front surface mounting and the rear surface mounting are overlapped. In comparison with the case where there is, the area in which the through hole 4 which must be provided avoiding the footprint 3 increases, and the degree of freedom in arrangement increases.

Further, since the SOP type SMDs 2 are mounted so that the terminal rows 6 of the power supply terminals 5 are overlapped on the front side and the back side, the power supply terminals 5 and the ground terminals 7 at the end of the row are provided on the intermediate layer. Each of the through holes 4 connected to the power supply wiring and the ground wiring can be shared by the shortest wiring between the front and back surfaces adjacent to the SOP type SMD 2 arranged in a line.

The reduction in the number of through holes 4 due to common use can improve the signal wiring density.

Thus, it is possible to provide a double-sided mounting of the SOP type SMD which improves the signal wiring density and increases the degree of freedom in the position of the through hole.

〔Example〕

Hereinafter, the gist of the present invention will be specifically described with reference to the embodiments shown in the drawings. Throughout the drawings, the same reference numerals indicate the same object,
FIG. 1 shows an embodiment of the present invention.

An example in which two SOP type SMDs 2 arranged adjacent to each other in one row are mounted on both sides will be described with reference to FIG. 1 as an embodiment.

In FIG. 1, the state on the front side is shown by a solid line, and the state on the back side seen through from the front side is shown by a dotted line. Overlaps of the same dimensions are indicated by double writing with the solid line inside and the dotted line outside. .

A footprint 3 is provided at each terminal position of the SOP type SMD 2 arranged in two rows of five terminals, and is a position overlapping on the front and back, and a terminal row 6 including the power supply terminal 5 also overlaps on the front and back. .

The position when the through hole 4 is provided is determined corresponding to each of the footprints 3, and the corresponding predetermined positions on both sides near the row of the footprint 3 of the terminal row 6 and the other terminal row 61, In the embodiment, the upper and lower positions and the end portions are provided at the left and right positions in the figure, the lower position is used on the front side, and the upper position is used on the back side.

The through-hole 4 is not a lead wire that penetrates or is a conventional large-sized one that performs soldering, and does not require soldering by the method of Via hole. The use of the small through-hole 4 having been performed in the above manner can sufficiently be applied to the SOP type SMD 2 having a narrow terminal interval.

〔The invention's effect〕

As described above, according to the present invention, since the footprints are overlapped on the front and back surfaces, the area for forming through holes is greatly increased, the degree of freedom is increased, the signal wiring cannot be connected, and the wiring rate is reduced. By improving the mounting direction on the front and back surfaces, the through holes for connection to the power supply wiring and the ground wiring on the intermediate layer can be shared on the adjacent front and back surfaces. Can reduce the number of through-holes corresponding to, the area for creating signal wiring increases by that amount, it is possible to improve the signal wiring density,
The effect is great.

[Brief description of the drawings]

 FIG. 1 is an embodiment of the present invention, and FIG. 2 is a mounting diagram of a conventional example of double-sided mounting. In the figure, 1, 15 is a printed circuit board, 2 is an SOP type SMD, 3 is a footprint, 4 is a through hole, 5 is a power supply terminal, 6 and 61 are terminal rows, and 7 is a ground terminal.

Claims (1)

(57) [Claims] 1. SOP type SMD on both sides of printed board (1)
For mounting (2), the footprint (3) of the SOP type SMD (2) is provided at a position overlapping on the front and back surfaces, and the through holes (4) are provided on both sides near the row of the footprint (3). A power supply terminal (5) provided at a predetermined position corresponding to the side.
SOP type SMD so that the terminal row (6) including
(2) A double-sided mounted SOP type SMD printed board characterized by mounting.