JPS60167395A - Printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a printed circuit board with a resistive layer, and particularly to an improvement in the wiring of the resistor.

[Background of the invention]

In a conventional printed circuit board with a resistive layer, components such as a semiconductor integrated circuit (IC) mounted on the board and a resistor formed in advance using the resistive layer of the board are connected to the signal layer of the board. Wiring connections were made using the provided wiring patterns to construct a desired logic circuit.

In this way, since the wiring pattern of the signal layer is also used for wiring with the resistor, problems such as the wiring pattern becoming crowded as the number of mounted components increases and the number of signal layers having to be increased arise.

In order to solve this problem, it is conceivable to use a land pattern for mounting components, etc., instead of using the wiring pattern of the signal layer for wiring with the resistor. However, since the terminals of the components to which the resistors are wired differ depending on the type of board, a mask for the top layer, which usually only requires one type, must be prepared for each type of board. For this reason, it is conceivable to prepare a wiring pattern on the top layer that connects all the terminals of components that may be connected to the resistor for each product type, but unnecessary wiring patterns for each product type may be prepared. must be cut, resulting in decreased reliability and increased man-hours.

[Purpose of the invention]

In view of the above, an object of the present invention is to eliminate the problems of the conventional technology and its improved technology as described above, and to eliminate the problem of increasing the number of types of masks, decreasing reliability, and increasing man-hours. It is an object of the present invention to provide a printed circuit board with a resistive layer that can substantially eliminate a wiring pattern with a resistor.

[-Summary of the invention]

In order to achieve such an object, the present invention uses a resistive layer to form resistors in advance at all terminal positions where there is a possibility of connecting to a resistor at the terminals of the 181-type component, and the resistors are formed in advance at all terminal positions that may be connected to a resistor. It is characterized in that selective holes are drilled only at the terminal positions for actual connection.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1(a) and 1(b) are a top view and a sectional view of a printed circuit board with a resistive layer, which is an embodiment of the present invention.

Components, for example IC2, are mounted on the surface of the board.

The substrate includes an insulating base material 20, conductor layers 13 to J8, and a resistance layer 19. A necessary pattern is formed on the conductor layer by etching technology or the like, and it is divided into a signal wiring layer 15.16, a power supply layer 14.1.7, and a cap layer 13.18 depending on its purpose.

A necessary resistance pattern is formed on the resistance layer by etching technology or the like. A detailed diagram of the resistance pattern is shown in Figure 2 (
Shown in a) and (b). This figure shows the resistor 10 enlarged to 11 in Figure 1, Figure 2 (ε'') is its plan view, and Figure 2 (b) is X, -X' in Figure 2 (,). FIG. A resistor 10 having a predetermined resistance value is formed at a desired location on the conductor 17. The cap layer 13 is provided with a land pattern 4 for fixing the IC terminal 3, a resistance connection pad 5, and a signal wiring connection pad 6. Note that terminals that have no possibility of being connected to a resistor are of course not required to be connected to the resistor connection terminal 1. Resistors 10 and 11 are provided directly below the resistance connection pad. The wiring connection bat 6 is connected to the signal wiring pattern 12 of the signal layer through a through hole 8, and necessary wiring connections are made. Terminals that need to be connected to the resistor are connected to the resistor 10 by forming through holes 7 in the resistor connection pads. Similarly, through holes are not formed for terminals that should not be connected to resistors, and pad 9 and resistor J] are not connected.

FIGS. 3(a) and 3(b) are a top view and a front view showing another embodiment of the present invention, and the same reference numerals indicate the same parts as in the previous embodiment. If the second problem arises in the configuration of the above embodiment, the resistor connection pad and the wiring connection pad can be used in common.
One pad 30 is used, and a plurality of resistive layers (36, 36,
37), and a plurality of resistors (38,
39). The pad 32 is connected only to the signal layer through the through hole 35, and the pad 34 is connected to the signal layer and one resistor through the through hole 34.
Pad 33 is connected to a signal layer and two resistors. In this way, it is possible to connect a resistor only to the necessary terminals and change the resistance value.

〔Effect of the invention〕

With the configuration as described above, the present invention can obtain the following effects. That is, (1) Since the wiring pattern with the resistor can be substantially eliminated, the mounting density of components can be increased.

■ The conductor pattern on the top layer of the board can be standardized.
The mask for that purpose is a big hood; it is intimidating.

■ When selecting the resistor connection, it is not necessary to cut any wiring pattern of the resistor, so it is possible to improve the simplicity and reduce the number of man-hours.

■ There are many cases where it is necessary to disconnect the terminals of a component and the signal wiring pattern due to changes in logic, etc., but leave the connections between the terminals and the resistor as they are, especially in the example shown in Figure 1. This can be easily realized by cutting the conductor pattern between the pads 5 and 6.

[Brief explanation of drawings]

FIGS. 1(5) and 1(b) illustrate the configuration of an embodiment of the present invention. FIGS. 2(,) and (b) are partially enlarged views, and FIGS. 3(a) and (b) are views of other embodiments of the present invention.
FIG. Vil Figure (α) Figure 2 (α) 3I21 (α)

Claims (1)

[Claims] A printed circuit board consisting of multiple layers, in which a resistor is formed in advance in a predetermined layer below a terminal of a component mounted on the board, and the resistor and a predetermined terminal are connected by a hole. Features printed circuit board.