JP2857823B2 - Electronic component mounting structure on circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of an electronic component on a circuit board, and more particularly to an electronic component having a plurality of terminals on both opposite sides of a narrow pitch multi-pin type electronic component such as an LSI. In a case where a predetermined circuit is electrically connected via an upper wiring pattern to configure a predetermined circuit, a mounting space including the wiring pattern can be significantly reduced.

[0002]

2. Description of the Related Art For example, a chip network resistor 1 having the circuit of FIG.
Is connected as a pull-up resistor to an LSI 2 such as a microcomputer, the wiring pattern to connect the pins 3 of the LSI 2 and the terminals 4 of the chip network resistor 1 on the substrate 5 is a conventional one. It was common sense to use something like that shown in Figure 4.

[0003] That is, the chip network resistor 1 has an elongated rectangular planar shape, and a plurality of terminals 4 are arranged at equal intervals on both sides of the chip network resistor 1.
In forming a wiring pattern for connecting these terminals 4 to predetermined pins 3 of the LSI 2, respectively, the L in the chip network resistor 1 is formed.
The wiring 6 connecting the terminal 4a on the opposite side to the SI2 and the LSI 2 is formed so as to bypass the planar shape of the chip network resistor 1.

Then, the area of the detour-shaped wiring pattern occupied by the detour-shaped wiring pattern on the circuit board increases because the wirings extending from the terminals 4a are not allowed to cross each other. Problem arises. This tendency becomes stronger as the number of terminals of the chip network resistor 1 increases,
As a result, the mounting density of electronic components on a limited area circuit board is significantly reduced. In other words, when forming a predetermined circuit, the size of a circuit board on which components for that purpose are to be mounted cannot be reduced to a predetermined size or less. In spite of using an LSI or a chip network resistor developed with the aim, the circuit board to be mounted cannot be reduced in size to a predetermined size or less.

The present invention has been conceived in view of the above circumstances. An electronic component having a plurality of terminals on both opposite sides is electrically connected to an electronic component such as an LSI on a circuit board. It is an object of the present invention to substantially reduce a substantial mounting space, including a wiring pattern for the connection, and to remarkably increase a component mounting density.

[0006]

Means for Solving the Problems To solve the above problems, the present invention takes the following technical means.

That is, the present invention provides a first electronic component having a plurality of terminal pins on at least one side at an equal pitch;
A second electronic component having a plurality of terminals on a first side close to the first electronic component and a second side opposite to the first side, a plurality of terminals on one side of the first electronic component; A mounting structure of an electronic component mounted on a circuit board so as to electrically connect pins and respective terminals of a first side and a second side of the second electronic component, wherein wiring on the circuit board is provided. The conductor pattern extends from each pad connected to each terminal on the first side toward a predetermined terminal pin on one side of the first electronic component, and From each pad connected to each terminal on the two sides, a conductor pattern extends under the second electronic component toward a predetermined terminal pin on one side of the first electronic component, and the circuit board In the region between the first electronic component and the second electronic component above, The conductor pattern extending from each pad connected to each terminal of the first side portion and the conductor pattern extending from each pad connected to each terminal of the second side portion are alternately, and It is characterized in that it is formed at a pitch of about half the pitch between terminals of the two electronic components.

[0008]

The invention of the present application is, in short, a terminal on both sides of an electronic component (second electronic component) having a plurality of terminals on both sides, and a multi-pin electronic component such as an LSI (first electronic component). A terminal on the side opposite to the first electronic component (the second side) of the second electronic component and the first electronic component The wiring pattern for connecting to the predetermined terminal pin is not formed so as to bypass the planar shape of the second electronic component as before, but under the second electronic component, that is, by forming extending the conductor in a first electronic component direction from the corresponding pads and the terminals opposite to the first electronic component (second side), one of the first electronic component on the circuit board In the area between the side and the first side of the second electronic component A conductor pattern extending from each pad connected to each terminal on the first electronic component side (first side) of the second electronic component, and the first electronic component of the second electronic component. The component and the conductor pattern extending from each pad connected to each terminal on the opposite side (second side) are formed alternately and at a pitch of about half the terminal pitch of the second electronic component. That's what I did.

[0009] Of the terminals of the second electronic component, each terminal located on the first electronic component side (first side) and the first electronic component.
The wiring pattern for connecting the one side of the terminals of, course, the shortest distance, ie, than it is extended respectively toward the one side of the terminal of the first electronic component from the corresponding pads to each terminal After the conductor pattern extending from each terminal on the opposite side (second side portion) of the first electronic component passes under the second electronic component, the respective terminal pads on the first electronic component side, respectively. , And extends toward the terminals on one side of the first electronic component. The pitch of the wiring pattern between one side of the first electronic component on the circuit board and the first side of the second electronic component is approximately equal to the pitch between terminals on each side of the second electronic component. It is a high density of half.

Furthermore , in the conventional mounting structure of this type of electronic component, a region hidden under the electronic component is not used as a region for the wiring pattern. The space on the substrate was wasted twice, but in the present invention,
Such double waste can be completely eliminated, and the wiring space can be reduced as a whole. This effect is
Electronic components have very narrow terminals like LSI
This is remarkable when formed at intervals.

Therefore, the mounting area of the first electronic component and the second electronic component on the circuit board, including the area occupied by the wiring pattern, is significantly reduced as compared with the prior art, and higher-density component mounting is achieved. Is achieved. In other words, when configuring circuits having the same function on a circuit board, the size of the circuit board for that purpose can be significantly reduced,
This can contribute to further downsizing of an electronic device equipped with such a circuit. In addition, the wiring pattern can be
To minimize wiring resistance.
There is a side effect of being able to do it.

Further, conventionally, it has been necessary to leave a space for a wiring pattern on both sides of the second electronic component, that is, a region opposite to the first electronic component is also provided.
Since it was necessary to keep a space for the wiring pattern, the position where the second electronic component should be arranged was limited accordingly, and the degree of freedom of the circuit configuration on the board was limited. Since there is no need to leave a region of the second electronic component opposite to the first electronic component as a space for a wiring pattern, for example, the second electronic component is arranged at a corner of a circuit board. For example, the degree of freedom for arranging components on a circuit board or forming a wiring pattern is significantly improved as compared with the related art. This also contributes to a higher density of component mounting on the substrate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to FIGS.

In this embodiment, a chip network resistor 11 as a second electronic component is electrically connected to a part of a large number of terminal pins 13 provided in an LSI 12 such as a microcomputer as a first electronic component. This is an example applied to connection.

As the form of the LSI 12, a resin package type surface mount type is adopted, and a large number of terminal pins 13 are provided at equal intervals from the side of a resin package 14 having a rectangular planar shape. ing. The above LSI12
The chip network resistor 11 as a second electronic component is connected as a pull-up resistor to some of the many terminal pins 13.

As shown in FIG. 2, the chip network resistor 11 has a long rectangular shape in plan view, and a plurality of terminals 1 are provided on opposite long sides thereof.
, 15b are formed at equal intervals. As the internal circuit configuration of the chip network resistor 11, there are various types. For example, a configuration having an internal circuit configuration as shown in FIG. 3 can be used.

On the other hand, an LSI as the first electronic component
A predetermined wiring pattern is formed on a circuit board 16 on which the chip network resistor 12 as the second electronic component 12 is mounted. A wiring pattern is formed on the circuit board to configure a circuit having a certain function.
Only the wiring patterns related to the connection between the LSI 12 and the chip network resistor 11 are shown. Naturally, it goes without saying that various other electronic components are mounted on the circuit board to form a predetermined electronic circuit.

In this embodiment, the LSI 12 and the chip network resistor 11 are both configured as a surface mount type. Therefore, the wiring pattern 17 for electrically connecting these components is Pads 17a to which the terminal pins or terminals are connected by soldering.
And conductive patterns 17b connecting the pads. Such a wiring pattern is formed by a known method. That is, a copper foil is formed on a substrate material such as glass epoxy, and a pattern is formed by etching the copper foil, and a resist coat is applied to portions other than the pads 17a.

In the present invention, first, the positional relationship between the two components is set so that the arrangement direction of the terminal pins of the LSI 12 and the direction of the two rows of terminal arrangements on both sides of the chip network resistor 11 are parallel.

The wiring pattern 17 is configured as follows.

First, the chip network resistor 11
Of the two rows of terminals, each terminal 15 which is closer to the LSI 12
a from the respective pads 17a on which the terminal pins of the LSI 12 are mounted.
Is formed.

Then, the above chip network resistor 1
Terminal 1 farthest from LSI 12 of the two rows of terminals 1
5b... Are placed on the respective pads 17a, LS
The conductor patterns 17b are respectively extended toward the pads 17a on the LSI 12 side so as to pass under the chip network resistor 11 toward I12.

Therefore, the conductor patterns 17b extending from the pads 17a remote from the LSI 12
After extending under the chip network resistor 11 toward the LSI, it extends between the conductor patterns extending from the respective pads on the side closer to the LSI. For this purpose, the above conductor pattern is used for the chip network resistor 1.
1 is bent in a crank shape at a portion located below the portion 1.

In the above embodiment, there are five terminals on both opposite sides of the chip network resistor 11, respectively, and therefore, two rows of five pads on which the above terminals are to be mounted are formed on the substrate. The conductor patterns extending from these ten pads all extend toward the LSI 12. As a result, the area on the substrate from the chip network resistor 11 to the LSI 12 is 1
.. Will be formed.
These ten conductor patterns 17b can be formed at equal intervals, and the pitch of these conductor patterns is half the pitch between the terminals of the chip network resistor 11.

In an LSI to which this kind of chip network resistor is to be connected as a pull-up resistor, the number of pins with a narrow pitch is increasing, so that the pattern from the chip network resistor is replaced with a terminal having such a narrow pitch. In the present invention, the pitch interval of the wiring patterns extending to the pads on the chip network resistor side is naturally reduced, so that the pitch of the terminal pins of the LSI can be reduced. It can also respond.

As is apparent from a comparison of FIG. 1 with the conventional example of FIG. 4, the electronic component mounting structure of the present invention does not require a wiring bypassing the chip network resistor 11, which is the second component. As compared with the related art, there is an excellent advantage that the mounting area of the electronic component including the wiring pattern is significantly reduced, and the mounting density of the electronic component on the circuit board is accordingly increased.

The L of the chip network resistor 11 is
Since there is no need to leave a space for providing a wiring pattern in the area opposite to the SI 12, there is no problem even if the chip network resistor 11 is arranged at a corner of the circuit board. Thus, according to the present invention,
The degree of freedom in arranging the electronic components on the circuit board is increased, so that it becomes easier to design the wiring pattern, which also contributes to increasing the component mounting density.

Further, since the distance of the conductor pattern from each pad for the chip network resistor to the connection pad on the LSI side is averaged, not only the line resistance in the conductor pattern is reduced, but also the line resistance is reduced. In addition, there is an additional effect that it is possible to prevent a decrease in the function of the entire circuit or a decrease in the stability due to the irregularity.

Of course, the scope of the present invention is not limited to the above embodiment. The mounting form of the component may be a surface mounting type, or may be a type in which terminal pins are inserted and mounted. In this case, the form of the pad to which the terminal is to be connected is merely replaced by the one with a hole.

The first electronic component or the second electronic component is not limited to an LSI or a chip network resistor. In short, the invention of the present application is applied to all cases where an electronic component having two rows of terminals on both sides is connected to each other while electrically connecting the terminals to a first electronic component having many terminal pins. It is possible.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a plan view of a chip network resistor as an example of a second electronic component.

FIG. 3 is an example of a peripheral circuit diagram of a chip network resistor.

FIG. 4 is a plan view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 11 chip network resistor (second electronic component) 12 LSI (first electronic component) 13 terminal pin (of first electronic component) 15a, 15b terminal (of second electronic component)

Claims (1)

(57) [Claims] 1. A first electronic component having a plurality of terminal pins on at least one side at an equal pitch, and a plurality of terminal pins on a first side close to the first electronic component and a second side opposite thereto. A second electronic component having terminals of the first electronic component, and a plurality of terminal pins on one side of the first electronic component, and electrically connecting each terminal of the first side and the second side of the second electronic component . A mounting structure of an electronic component mounted on a circuit board so as to be connected to the circuit board. While extending toward a predetermined terminal pin on one side of the electronic component, a conductor pattern passes under the second electronic component from each pad connected to each terminal on the second side. extending toward a predetermined terminal pins on one side of the first electronic component In a region between the first electronic component and the second electronic component on the circuit board, the conductor pattern extending from each pad connected to each terminal on the first side portion and the second A conductor pattern extending from each pad connected to each terminal of the side portion, alternately, and is formed at a pitch of about half of the pitch between the terminals of the second electronic component, The mounting structure of electronic components on a circuit board.