JPH0770656B2 - High power transistor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high-power transistor that operates at high power.

[Prior Art] FIG. 6 is a perspective view showing a conventional high-power transistor. In the figure, 1 is a mounting seat for mounting the high-power transistor on a heat sink, and 2 is a mounting chip formed by an insulating material having a high thermal conductivity and not shown in FIG. It is a base attached on top of 1. Reference numeral 3 denotes a connector by a flat lead which is attached to the base 2 and can be connected to, for example, an emitter of a transistor chip mounted on the base 2 by bonding or the like to form a common ground, and 4 is attached to the base 2. A flat lead connector that can be connected to, for example, the collector of the transistor chip to serve as an output terminal, and a flat lead connector that can also be attached to the substrate 2 and connected to, for example, the base of the transistor chip to serve as an input terminal Is. Reference numeral 6 is a protective cap provided on the base 2 to protect the transistor chip and its bonding and the like.

Next, the operation will be described. Here, FIG. 7 is a circuit diagram showing a high-frequency high-output circuit using the high-output transistor having the above configuration. This high output transistor is connected to each connector 3 ~
Attached to the printed wiring board by soldering 5
For example, the power amplification of the input power is performed by the amplification action by the class C operation. In such a high frequency and high output circuit, it is necessary to perform impedance matching between the high output transistor and the circuit to which it is connected. And a coil 7b are connected for output matching, and similarly, a connector 7 for input matching on the printed wiring board and a coil 7d are connected to the connector 5 for input matching. In these impedance matching, matching is performed in consideration of the inductance component of the connector 4 or 5 of the high output transistor.

[Problems to be Solved by the Invention]

Since the conventional high output transistor is configured as described above, when operating with a large amount of power, heat generated in the transistor chip is transmitted from the connectors 3 to 5 to the printed wiring board, and the connectors 3 to 5 are soldered. Not only becomes a factor of deteriorating the reliability over time in the joint part of the connector 4, which becomes an output terminal in which a large amount of current flows, but also the shape of each connector 3-5 is fixed, and The inductance components of the children 4 and 5 affect the configuration of the high frequency and high output circuit, and the matching circuit becomes complicated to obtain the desired characteristics, the number of parts increases, and the adjustment becomes complicated. There was a point.

The present invention has been made to solve the above problems, and to improve the reliability of soldering over time, and to obtain a high output transistor that is easy to obtain the desired characteristics in a high frequency high output circuit. To aim.

[Means for Solving the Problems]

The high-power transistor according to the present invention exposes a part of the surface of the base on which the transistor chip is mounted from the protective cap, and is connected to the transistor chip, and further has a connection terminal to which a connection lead for external connection is connected, It is arranged in close contact with the exposed surface of the base.

[Action]

In the high output transistor according to the present invention, instead of the fixed-shaped connector, the connection terminal to which the connection lead for external connection is connected is arranged in close contact with the surface exposed from the protective cap of the base. , It is possible to efficiently dissipate the heat generated by the transistor chip through the substrate and to use the connection leads having the desired characteristics, and easily obtain the desired characteristics in the high frequency and high output circuit. Realizes a high output transistor that can

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a mounting seat, 2 is a base, 3 and 5 are connectors with flat leads, 6 is a protective cap, which is the same as or equivalent to those of the conventional ones given the same reference numerals in FIG. Detailed description is omitted.

Reference numeral 8 denotes an exposed surface of the substrate 2 which is not covered by the protective cap 6, and 9 is connected to a transistor chip not shown in FIG. The connection terminals are arranged in close contact with the exposed surface 8. One end of 10 is connected to a printed wiring board (not shown) by soldering, and the other end is connected to the connection terminal 9 by, for example, soldering so that the high output transistor is connected to the outside. A connection lead that realizes connection and has a length, width, and thickness according to the required characteristics. Also, by providing a number of interdigital slits, the heat dissipation characteristics are improved. .

Next, the operation will be described. Here, FIG. 2 is a circuit diagram showing a high-frequency high-output circuit using the high-output transistor having the above configuration. This high-power transistor is attached to the printed wiring board by soldering each of the connectors 3 and 5 and the connection lead 10 connected to the connection terminal 9, and for example, the input power is amplified by the amplification action by the class C operation. Power amplification is performed. Therefore, in the connection terminal 9 arranged in close contact with the exposed surface 8 of the base 2, even if a large amount of current flows therethrough and a large amount of heat is generated, the base 2 made of an insulating material having high thermal conductivity is used. The heat is quickly dissipated by.

Output impedance matching in such high-frequency and high-power circuits is arranged on the printed wiring board by connecting leads.
Connected to 10. The output matching capacitor 7a and the coil 7b are used. Similarly, the input impedance matching is performed by the input matching capacitor 7c and the coil 7d which are arranged on the printed wiring board and connected to the connector 5. ing. The impedance matching is performed in consideration of the inductance components of the connection lead 10 and the connector 5, and therefore, the connection lead 10 having a length, width, and thickness suitable for the desired characteristics is used. By selecting the matching circuit, the matching circuit can be made simple with a small number of parts, and the adjustment thereof can be simplified.

FIG. 3 is a perspective view showing another embodiment of the present invention. In this embodiment, a third connector is used instead of the conventional connector 4.
Board 2 connected to a transistor chip that does not appear in the figure
A connection terminal 9 disposed in close contact with the exposed surface 8 of
An electronic component such as an output matching capacitor 7a is provided between the high output transistor and a connector 3 that can be a common ground.
Is a direct connection. When the output matching capacitor 7a is connected in this way, the capacitor is connected between the connection lead 10 and the internal inductance of the high output transistor, and impedance matching can be easily performed while considering the Q of the circuit. Is possible. Further, the heat generated by the output matching capacitor 7a is also dissipated more quickly from the base plate 2 in which the connection terminals 9 are in close contact with the exposed surface 8, and the heat dissipation characteristics can be further improved. Here, the electronic component connected between the connection terminal 9 and the connection lead 10 is not limited to the above-mentioned capacitor, but may be another electronic component such as a resistor or a coil.

Incidentally, in the above embodiment, as the connection lead 10, the case of using a flat flat lead having a large number of interdigital slits, even if the shape of the slit is another shape, a simple flat lead without slit, Alternatively, it may be a bonding wire or a round lead, and further, a curved portion may be provided on them. FIG. 5 shows a connecting lead in which such a curved portion 11 is provided on a flat lead having a comb-like slit.
FIG. 10 is a perspective view showing an example of the connection lead 10 in this manner.
Even if the connecting lead 10 expands and contracts due to heat generation, the bending part 11 naturally has a stress due to expansion and contraction.
It is possible to prevent deterioration of reliability of the soldered portion over time due to absorption in 11.

Further, in the above-described embodiment, the case where only the connector 4 which can be an output terminal is replaced with the connection terminal 9 which is in close contact with the exposed surface 8 of the substrate 2, is described. The connector 5 that can become
The connection terminal may be replaced with a contact terminal that is in close contact with the exposed surface of the board 2. Further, in the above embodiment, the case where the connection lead 10 is connected to the connection terminal 9 when the high-power transistor is mounted has been described. Already, connection lead 10
May be connected to the connection terminal 9.

Further, in the above-described embodiment, the case where the high-output transistor has a rectangular shape has been described. However, the high-output transistor may have a round shape, and the same effect as that of the above-described embodiment can be obtained. The case where the high output transistor is used in the high-frequency amplifier circuit of class C operation has been described, but the high output transistor can be used in other high output circuits such as a switching circuit and a low frequency amplifier circuit.

〔The invention's effect〕

As described above, according to the present invention, instead of the fixed-shaped connector, the connection terminal to which the connection lead for connection with the outside is connected is arranged in close contact with the surface exposed from the protective cap of the base. Since it is configured so that it is possible to efficiently dissipate the heat generated from the transistor chip through the substrate, it is possible to prevent the deterioration of the reliability of the joint portion due to soldering etc. Since the interdigital slit is provided on the connector chip, even if the heat generated from the transistor chip conducts through the connection lead, the interdigital slit can dissipate the heat on the way. It is possible to prevent deterioration of the soldered portion and the like. In addition, it is possible to use the connection lead having a desired characteristic, and it is possible to easily achieve the desired characteristic in a high-frequency high-output circuit, etc. Since it can be easily mounted on the output transistor, errors in transistor manufacturing can be easily corrected from the outside, and a part of the electronic components of the external circuit can be mounted on this high-power transistor to simplify the external circuit. It is also possible to do so.

[Brief description of drawings]

FIG. 1 is a perspective view showing a high output transistor according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a circuit using the same, and FIG. 3 is a perspective view showing another embodiment of the present invention. , FIG. 4 is a circuit diagram showing an example of a circuit using the same,
FIG. 5 is a perspective view showing another embodiment of the connection lead, FIG. 6 is a perspective view showing a conventional high output transistor, and FIG. 7 is a circuit diagram showing an example of a circuit using the same. 2 is a base, 6 is a protective cap, 8 is an exposed surface, 9 is a connection terminal, and 10 is a connection lead. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A base made of an insulating material having a high thermal conductivity for mounting a transistor chip, the transistor chip mounted on the base and the bonding portion thereof are covered, and a part of the surface of the base is exposed. A protective cap disposed on the base, a connection lead connected to the transistor chip and closely attached to the exposed surface of the base, and a comb-like slit having one end connected to an external circuit. And a connection terminal whose other end is connected to the connection lead.