JPS6286841A - High frequency hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To stably operate a high frequency hybrid integrated circuit by covering a high frequency circuit with a metal film coated on a cap and metal conductors to become an earth surface to simplify working steps, thereby readily shielding the circuit. CONSTITUTION:A circuit board 2 composed of a high frequency circuit is entirely enclosed with metal conductors 1 to become an earth surface, a metal film 4 covered on a plastic cap 3 and a conductive adhesive 5 for connecting therebetween to be electrically shielded from the exterior. As a result, even when a metal plate is covered to be, for example, hermetically sealed from the exterior by the hybrid integrated circuit, the circuit is not affected by any influence but stably operated. Particularly, large effect is obtained in a high frequency high output hybrid integrated circuit and a filter circuit for handling large power in high frequency.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a high frequency hybrid integrated circuit.

[Conventional technology]

In circuits that operate at high frequencies, high frequency components are emitted from the line pattern or various used components, often having an adverse effect on other circuits around them.

In order to prevent such interference and stabilize the entire circuit as a system, it is common practice to cover the high frequency portion with a specially prepared metal plate.

Furthermore, the above-mentioned adverse effects become more pronounced as the frequency and power become higher, and such areas are shielded with metal plates in close contact with the components.

On the other hand, in recent years, the miniaturization of devices has progressed rapidly, and as a result, high-frequency hybrid integrated circuits have been forced to become smaller in terms of area and volume, and internal circuits have become increasingly dense.

In such highly integrated high frequency circuits, a potential difference occurs between the ground potential on the hybrid integrated circuit and the ground potential of the shield metal plate due to the way the metal plate for shielding is grounded. There was a problem in that it interacted with the line pattern impedance on the hybrid integrated circuit or the constants of the coils, etc., causing changes in the matching conditions of the circuit, and causing oscillations and the like.

A conventional technique for solving the above problem is shown in FIG. With this technology, the entire surface of the circuit board (2) fixed to the metal conductor (1) that serves as the ground is coated with a resin (6) that is insulating and has low loss at high frequencies, and then the metal conductor (1) The purpose is to shield the circuit by coating or molding conductive example U1 (71) so that an electrical connection can be established.

[Problem that the invention seeks to solve]

As described above, with conventional technology, the entire surface of the circuit board must be coated with a resin that has good insulation and high-frequency characteristics, and then it is necessary to coat or mold a conductive resin on top of that. The sealing process is complicated, often requires manual labor, and is expensive.

The present invention has been made to eliminate the above-mentioned drawbacks, and provides a high-frequency hybrid integrated circuit that can simplify the working process, easily shield the high-frequency circuit, and operates stably.

[Means for solving problems]

In the device according to the present invention, a plastic cap used in a hybrid integrated circuit is coated with a metal, and the metal film coated on the cap is fixed to a metal conductor serving as a ground plane with a conductive adhesive.

[For production]

In this way, the high frequency circuit will be covered by the metal film coated on the cap and the metal conductor serving as the ground plane, and the high frequency circuit will be electrically shielded from other circuits.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention. In the figure, (1) is a metal conductor that serves as a ground plane (sometimes serving as a heat sink), (2) is a high-frequency circuit board fixed on the metal conductor (1), and (3) is a high-frequency circuit board (2). ), (4) is a metal coating that is not covered on the inner surface of this plastic cap (3), and (5) is a plastic cap that protects the metal coating (4) and a metal conductor (1) that serves as a ground plane. A conductive adhesive that provides electrical and mechanical connections.

In the above configuration, the circuit board (2) on which the high frequency circuit is configured includes a metal conductor (1) serving as a ground plane, a metal coating (4) that is not covered by the plastic cap (3), and a space between them. It is completely surrounded by a conductive adhesive (5) for connection and is electrically shielded from the outside.

As a result, even if, for example, a metal plate is placed in close contact with the hybrid integrated circuit from the outside, the circuit is not affected in any way and can operate stably.

Particularly, according to the present invention, great effects can be obtained in high-frequency, high-output hybrid integrated circuits and filter circuits that handle large amounts of power at high frequencies.

〔Effect of the invention〕

As described above, according to the present invention, there is no need to go through a complicated process such as coating a high frequency circuit with two types of resin, and a high frequency hybrid integrated circuit can be constructed at low cost.
It also has the effect of accurately shielding the circuit.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention. FIG. 2 is a sectional view showing a conventional technique. (1) is a metal conductor serving as a ground plane, (4) is a metal coating fixed to the cap, and (5) is a conductive adhesive. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In a hybrid integrated circuit that is covered with a metal conductor that serves as a ground plane and a plastic cap that protects the circuit, a metal coating is applied to the inner surface or the entire surface of the plastic cap, and the metal coating is insulated from the main part of the circuit. A high frequency hybrid integrated circuit characterized in that the metal conductor serving as the ground plane is fixed with a conductive adhesive.