JPH04329692A - Both side mounting type memory package - Google Patents

Abstract

PURPOSE:To improve the pin arrangement of a memory IC on the both sides mounting type package and wiring characteristics of the package. CONSTITUTION:By using a backside memory IC2 whose pin arrangement is totally symmetrical with respect to the front side memory IC1, the front side memory IC1 is mounted on one side and the rear side memory IC2 whose pin arrangement is symmetrical with respect to this is mounted on the other side so that the pin arrangement of the common control signals for the memory IC is made the same as for the front and rear sides. It is possible to connect a pin having the same function as that of the front side memory IC1 and the rear side memory IC2 to one wiring pattern, thereby improving the wiring characteristics of the common control signal pattern.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided memory package, and more particularly to a double-sided memory package that improves the wiring of a memory IC.

0002

2. Description of the Related Art Conventionally, for example, as shown in FIGS. 6 and 7, a double-sided mounting type memory package has a printed circuit board
A pair of memory ICs 1 each having connection pins having the same function on the front and back sides of the memory IC 1 are wired facing each other.

[0003] A more specific explanation will be provided. FIG. 6 is a front view of the double-sided mount type memory package, and FIG. 7 is a perspective view of the back side thereof viewed from the front side. As is clear from the figure, since the pins of the memory IC 1 are symmetrical to each other on the front and back surfaces, as if mirrored, for example, the memory IC control signal pattern 5 is drawn separately on the front and back surfaces. In other words, there are two patterns for pins with exactly the same function.

Furthermore, when attempting to draw a pattern on either the front or back surface, two through holes 6 are required from the front surface to the back surface, resulting in poor wiring performance. Note that 4 is a lead line connecting the memory IC 1 and the memory IC control signal 5.

[0005]

[Problems to be Solved by the Invention] However, in the conventional double-sided memory package described above, the input/output pins of the memory ICs mounted on the front and back sides are the same, so if they are wired facing each other, However, there was a problem that the input/output pins no longer correspond to each other and are separated from each other, resulting in poor wiring of the common pins of the memory IC.

That is, in the conventional technology described above, the common control signals (address, etc.) of the memory IC in the double-sided memory package are
Misalignment occurred in the pin positions of the memory ICs mounted on the front and back surfaces, resulting in poor wiring performance.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a double-sided mounting type memory package with improved wiring performance.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the double-sided mounting type memory package of the present invention includes a front side memory IC and a back side memory IC each having connection pins having the same function on the front and back sides of a printed circuit board. In a double-sided memory package with wires facing each other, the connection pins of the front side memory IC and the connection pins of the back side memory IC are arranged in a symmetrical relationship such that pins having the same function correspond to each other in the facing state. be.

[0009]

[Operation] According to the double-sided mounting type memory package having the above configuration, when the front side memory IC and the back side memory IC are mounted, pins having the same function correspond to each other, so these pins can be connected together through a through hole or the like. Can be connected to the wiring pattern of the book.

0010

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are plan views showing a front side memory IC1 and a back side memory IC2 according to an embodiment of the present invention, and FIGS. 3 to 5 are plan views and cross-sectional views showing a double-sided mounting type memory package according to an embodiment of the present invention. They are a top view and a longitudinal cross-sectional view.

In FIGS. 1 and 2, the front side memory IC
1 and the back side memory IC 2 are formed with ten connection pins protruding left and right. And the front side memory IC
The connection pins 01 to 10 of the memory IC 1 and the connection pins 01 to 10 of the back side memory IC 2 are arranged in a symmetrical relationship such that pins having the same function correspond to each other while facing each other.

That is, in this embodiment, assuming that the memory IC1 is a conventional product, a pin-symmetrical type memory IC2 is used. 1 and 2, pins with the same numbers have the same function (meaning the same control signal).

In FIG. 2, the double-sided mounting type memory package has a memory IC control signal pattern 5 attached to a printed circuit board 3, and a through hole 6 for connecting the patterns on the front and back sides.

[0014] Then, the front side memory IC1 is mounted on the front surface of the printed circuit board 3 of the double-sided mounting type memory package, and the pin-symmetric type back side memory IC2 is mounted on the other side. code 4
is a lead line for efficiently wiring control signals of the memory IC.

That is, in this embodiment, the front side memory IC
1 is a conventional product, the conventional memory IC 1 is mounted on the front surface, and the pin symmetrical memory IC 2 is mounted on the back surface.

Therefore, as described above, when the memory ICs are mounted on the front and back sides, the pins with the same function of the memory ICs 1 and 2 are arranged at exactly the same position across the printed circuit board 3, and only one through hole 6 is provided. It is possible to connect with.

Furthermore, in the wiring of the memory IC control signal pattern 5, the lead wires 4 of the memory ICs mounted on the front and back surfaces are connected through a through hole 6.
is connected to memory IC control signal pattern 5.

Memory IC control signal pattern 5 includes memory IC common control signals (address, RAS, CAS, WE
etc.), and unlike the conventional technology in which patterns were wired on each of the front and back surfaces, the wiring efficiency is simply doubled compared to the conventional technology.

Furthermore, when attempting to wire the memory IC control signal pattern 5 on either the front or back side, the through hole 6
However, by using the method of the present invention, the number of through holes 6 can also be reduced by half.

[0020]

[Effects of the Invention] As explained above, according to the double-sided memory package of the present invention, a memory IC having a pin arrangement completely symmetrical to that of a conventional memory IC can be mounted on either the front or back side of the double-sided memory package. Therefore, it is possible to connect pins having the same function of the front and back memory ICs to one wiring pattern, and there is an effect that the wiring performance of the common control signal pattern of the memory ICs can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a front side memory IC used in a double-sided mount type memory package according to an embodiment of the present invention.

FIG. 2 is a plan view showing a back side memory IC used in a double-sided mount type memory package according to an embodiment of the present invention.

FIG. 3 is a plan view showing a double-sided mounting type memory package according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a double-sided mounting type memory package according to an embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a double-sided mounting type memory package according to an embodiment of the present invention.

FIG. 6 is a plan view showing a conventional double-sided mounting type memory package.

FIG. 7 is a perspective plan view showing the back side of a conventional double-sided memory package.

[Explanation of symbols]

1 Front side memory IC 2　Back side memory IC 3 Printed circuit board 4 Lead line 5 Memory IC control signal pattern 6 Through hole

Claims (1)

[Claims] 1. In a double-sided memory package in which a front side memory IC and a back side memory IC each having connection pins having the same function are wired facing each other on the front and back sides of a printed circuit board, the connection pins of the front side memory IC and the back side memory IC are wired facing each other. A double-sided mounting type memory package characterized in that connection pins of an IC are arranged in a symmetrical relationship such that pins having the same function correspond to each other when facing each other.