JPH0731557Y2 - Printed board - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a printed circuit board on which an IC (integrated circuit) is mounted.

(B) Conventional technology Normally, the terminals of an IC are active terminals having some function except for the power supply terminal and the ground terminal. When the function is not operated, the terminal is grounded. Therefore, IC
It is necessary to separately prepare a printed circuit board on which ICs having different conductor patterns are arranged depending on whether the specific function of (3) is activated or not. For this reason, material costs and management costs associated with the increase in the types of printed circuit boards increase.

As an example, an IC for VIF (video intermediate frequency) of a television receiver will be described with reference to FIG. (1) is VI
IC for F, (2) TV tuner, (3) SAW
It is a (surface acoustic wave) filter.

Here, when the television tuner (2) is of the voltage synthesizer type, the AFT (automatic frequency adjustment) voltage is fed back to the tuner (2) as shown in FIG. 2 to control the frequency. In this case, the AFT coil (6) and the tuning capacitor (7) are connected in parallel between the terminals (4) and (5) of the IC (1) to form an AFT tank circuit.

On the other hand, when the tuner (2) is of the frequency synthesizer channel selection system, the local oscillation frequency is controlled by the microcomputer so as to be locked at a predetermined frequency, and therefore it is not necessary to feed back the AFT voltage. For this reason, the AFT circuit is not required, so the terminals (4) and (5) for the AFT tank of the IC (1) are free.
Therefore, in order to operate other functions of IC (1) stably, AF
T tank terminals (4) and (5) must be grounded.

In such a case, VIF I
It is necessary to prepare printed circuit boards with different conductor patterns to which C (1) is attached. However, since the cost increases, it is preferable that only one type of printed circuit board can be used.

Therefore, as shown in FIG. 3, it is conceivable to form a conductor pattern such that the active terminals not used by the IC (1) can be grounded by the chip jumpers (8) and (9). FIG. 3 is an enlarged view of a main part of a conductor pattern forming surface on the back surface side of the surface of the printed board to which the IC (1) (not shown) is attached.

In the figure, (10) to (13) are terminals (4) of the IC (1).
The through holes (5), (14) and (15) are inserted. (16) ~
Reference numeral (19) is a land for solder connection of the terminals (4), (5), (14) and (15), which is formed on the periphery of the through holes (10) to (13). (20) is a conductor pattern for grounding. (21) ~ (2
Reference numeral 4) is a conductor pattern that is connected to the lands (16) to (19) and is used to connect circuit parts (not shown) to the terminals (4) (5) (14) (15) of the IC (1).

The chip jumpers (8) and (9) are respectively connected to the land (17) (1) when the terminals (4) and (5) of the IC (1) are not used.
8) and the grounding conductor pattern (20). The chip jumpers (8) and (9) are attached by gluing them in predetermined positions, fixing them by thermosetting, and dipping by soldering.

In this way, the chip jumper (8) (9) depends on whether the function of the active terminal is always activated or not activated.
At, a conductor pattern is formed so that a predetermined terminal can be grounded.

Now, the chip jumpers (8) and (9) are land (1
7) Soldered over the (18) and the grounding conductor pattern (20). At this time, chip jumper (8)
There is a problem that solder bridges occur between the electrodes (25) and (26) of (9), which are close to the lands (16) and (19) that are close to the adjacent lands (16) and (19).

To prevent such solder bridging, the land (17) (18) or conductor pattern (22) for the terminal to be grounded
The conductor pattern is extended from the middle of (23) to a position where it is separated to the extent that the chip jumper (8) (9) is bridged over the grounding conductor pattern (20). A possible method is to separate the soldering position from the lands (16) (19). However, this method is impossible if there is no space on the printed circuit board due to the miniaturization of the device. Further, in a high-frequency circuit, an extra conductor pattern is required to be grounded immediately because stray capacitance and a pattern inductor are generated, and therefore it is uncomfortable to ground it away from the terminal.

(C) Problems to be Solved by the Invention The present invention solves the above-mentioned problems in a printed circuit board on which a conductor pattern capable of selectively grounding a plurality of adjacent terminals of an arranged IC with a chip jumper is formed. In addition, it is intended to reduce the manufacturing cost.

(D) Means for Solving the Problems The present invention provides a printed circuit board in which an IC having a plurality of terminals is arranged, and a conductor pattern for electrically connecting the terminals of the IC is formed on an insulating substrate. A plurality of lands that are connected to the conductor pattern and whose terminals of the IC are connected by soldering, a grounding conductor pattern formed at a predetermined distance from the lands, and an electric component among the lands At least two adjacent lands for connection, each of which has an end portion formed to extend toward the grounding conductor pattern, one end of the plurality of adjacent lands straddling the other end, and The electrical component connection land is grounded by a chip jumper that is bridged over the grounding conductor pattern.

(E) Operation With the above configuration, one end of the chip jumper is electrically connected to the plurality of terminals of the IC to be grounded, and the other end is connected to the grounding conductor pattern to ground the terminal of the IC.

(F) Embodiment One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged view of an essential part showing a printed circuit board according to the present invention. The same or similar parts as those of the conventional example shown in FIG.

3 is different from that shown in FIG. 3 in that the land (17 ') (18') has an end (17 ") extending toward the grounding conductor pattern (20).
(18 ″) is formed, and when the terminals (4) and (5) of the IC are grounded, one chip jumper (27) has one end with land (17 ′) (18 ′) end (17 ″) (18) ″), And is laid across the grounding conductor pattern (20). And the ends (1) of the lands (17 ′) and (18 ′)
7 ″) and 18 ″ are formed at intervals such that the electrodes (28) at one end of the chip jumper (27) straddle each other and are surely electrically connected.

The chip jumper (27) is glued and fixed at the position shown in FIG. 1 and soldered. At this time, a solder bridge is generated between the electrode (28) of the chip jumper (27) and the terminals (4) and (5) of the IC to make an electrical connection. Since the electrodes (28) of the chip jumper (27) and the terminals (14) (15) of the IC are separated from each other, a solder bridge does not occur between them.

Further, as described above, since the plurality of adjacent terminals (4) and (5) are grounded by the single chip jumper (27), the number of parts can be reduced and the cost can be reduced. In this embodiment, the grounded IC has two terminals, but the present invention can be applied to three or more adjacent terminals. That is, in this case, the land ends are formed so that the ends of the electrodes of the chip jumper bridge the terminal lands located at both ends of the plurality of terminals, and the chip jumpers are arranged.

(G) Effect of the Invention As described above, according to the present invention, two types of circuits using the same IC can be configured with one type of printed circuit board, and one chip jumper grounds the IC terminal. Because it can be done, it is possible to reduce the cost. Moreover, since the electrode of the chip jumper provided is separated from the non-grounded terminal adjacent to the grounded terminal, a solder bridge does not occur between the electrode of the chip jumper and the electrode. Furthermore, since it is grounded by the chip jumper in the immediate vicinity of the IC terminal, performance in a high frequency circuit is guaranteed and it contributes to downsizing of the device.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of a printed circuit board of the present invention, and FIGS. 2 and 3 are views for explaining a conventional example. (4) (5) (14) (15) ... IC terminals, (16) (17 ')
(18 ') (19) ... land, (17 ") (18") ... end,
(20)… Ground conductor pattern, (27)… Chip jumper.

Claims (1)

[Scope of utility model registration request] 1. An IC having a plurality of terminals is provided, and the IC is provided.
A printed circuit board on which a conductor pattern to which each terminal is electrically connected is formed on an insulating substrate, a plurality of lands connected to the conductor pattern, the terminals of the IC being connected by soldering, A grounding conductor pattern formed at a predetermined distance from the land, and an end formed by extending to the grounding conductor pattern side on at least two adjacent lands for connecting electrical parts in the land. One end of the plurality of adjacent lands is straddled, and the electrical component connecting land is grounded by a chip jumper bridged between the land and the grounding conductor pattern. Printed board.