JP3471903B2 - Chip type variable temperature attenuator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the use of semiconductors to control the power following changes in the ambient temperature of power amplifiers widely used in electronic communication equipment and measurement equipment. The present invention relates to a chip-type variable temperature attenuator mounted on a surface of a device which is used for making it possible to always adjust the size and which is being reduced in size and resource saving. 2. Description of the Related Art Generally, in addition to forming a T-type or a 減 衰 -type attenuator by combining three single resistors, a temperature detecting element is used, and an output is made using more than ten electronic parts. An electronic circuit for adjustment is loaded on the power amplifier, and adjustment for high frequency, temperature characteristic adjustment, and the like are performed, and a certain place and human time are required to achieve the purpose. [0003] However, a conventional circuit for adjusting a change in ambient temperature to obtain a constant output has a large number of parts, and a special technique is required especially for use in a high frequency region. Equipment, which requires a lot of time for adjustment, and for devices that require short, thin and light,
The size occupied by the circuit was also a very troublesome problem. [0004] The present invention is a chip type which can be easily mounted without solving the above-mentioned drawbacks and does not cause anxiety in the characteristics of the device, and has a very small size conforming to the standards of surface mount parts. Not only is it effective for miniaturization of equipment, but also based on a chip-type fixed attenuator developed in-house (Japanese Utility Model Application No. 4-46701). Is provided. [0005] The gist of the present invention will be described with reference to the accompanying drawings. A metal thin-film resistor 2 is formed substantially at the center of the upper surface of a rectangular substrate 1, and one side end of the metal thin-film resistor 2 is formed on one side of the rectangular substrate 1 so as to have a U-shaped cross section extending over the upper surface and the lower surface. A first electrode 3 is formed in contact with the metal thin film resistor. The second electrode 4 and the third electrode 5 are formed so as to be in contact with the other corners of the first electrode 1 respectively, and the metal thin film resistor 1 is covered with a protective coat 6 for shutting off outside air. The present invention relates to a chip-type variable temperature attenuator in which a block-shaped chip-type temperature variable resistor 7 whose resistance value changes according to a change in ambient temperature is externally provided. For example, as shown in FIG. 6, an adhesive material 10 provided in the mounting recess 9 of the base 8 and a solder 10 'provided in the periphery of the mounting recess 8 are melted by heat, and as shown in FIG. Mount on the surface of The first electrode 3, the second electrode 4, and the third electrode 5 are all formed in a U-shaped cross-section extending over the upper surface, the side surface, and the lower surface of the rectangular base 1, so that the surface mounting can be performed reliably. Become. Which side is used as an input terminal or an output terminal can be changed as appropriate (input and output expressions are distinctions for explanation, and it can be said that there is no functional difference). Assuming that the first electrode 3 is an input terminal and the third electrode 5 and the first electrode 3 are output terminals, the present device equivalently becomes a Π-type temperature compensation circuit as shown in FIG. The input / output impedance depends on the resistance of the thin-film resistor 2, and the resistance between the input and output depends on the resistance of the resistor 2 and the temperature variable resistor 7. For example, the temperature variable resistor 7 Assuming that it has temperature negative characteristics,
The negative gain (-At) as the attenuator decreases as the temperature rises as shown in FIG.
(The gain (At) of the amplifier rises as the temperature rises. In FIG. 8, since the vertical axis indicates −db, the graph falls as a negative gain.) Conversely, if the temperature characteristic of the temperature variable resistor 7 is set to the positive characteristic, the temperature characteristic of the gain (At) is reversed as shown by the dotted line in FIG. The negative gain (-At) increases. Therefore, when a chip-type variable temperature fixed attenuator (this device) having a negative gain temperature characteristic as shown by a solid line in FIG. 8 is connected to the amplifier 11 as shown in FIG. Works. As described above, the amplifier 11 is, for example, a high-performance C
Assuming that an aAs-based semiconductor element is used, the gain G ′ thereof decreases as the temperature rises, as shown in FIG. On the other hand, the gain At of the device increases as the temperature rises as described with reference to FIG.
B, but in Figure 9 it is + dB, so
The graph of At rises. ). Accordingly, the total gain G is compensated by the negative temperature characteristic of the gain At of the present apparatus and does not vary with temperature change (total gain), as shown in FIG.
G can be obtained. Similarly, if the temperature characteristic of the amplifier is a positive characteristic, it can be compensated by connecting a main unit having a negative temperature characteristic so that the total gain G does not fluctuate in response to a temperature change. Can be stabilized. In such a 減 衰 -type attenuation circuit, the attenuation of the amount of power transmitted from the input to the output is represented as the attenuation of the attenuator. The measured resistance value is the impedance with the attenuator connected, but the impedance seen from the input is ideally the same as the output impedance regardless of whether the attenuator is connected or not. If it changes, reflection will occur in the circuit, degrading the characteristics. Therefore, the attenuator is designed so that the impedance of the output is equal to the impedance seen from the input (for example, if the output is 50Ω, the attenuator is connected so as to be 50Ω when seen from the input). . EXAMPLE This example is manufactured by the following procedure. (1) A multilayer metal film is deposited as a metal thin film resistor 2 on at least the upper surface of a ceramic rectangular substrate 1 having excellent thermal conductivity and mechanical strength. (2) Further, copper for forming an electrode is overlaid and vapor-deposited on the entire surface. (3) Unnecessary portions are removed by etching in order to use the copper for the electrodes. (4) After the metal thin film resistor 2 exposed by the etching of (3) is formed into a pattern shape having a predetermined attenuation and characteristic impedance by etching, special trimming further corrects it, and The second electrode 4 is formed so as to be an element equivalent to a type or Π type resistor.
In addition, the resistance is corrected to a desired resistance value synthesized by the characteristics, resistance value, and the like of the temperature variable resistor 7 attached between the third electrodes 5. (5) The exposed surface of the metal thin film resistor 2 is coated with a protective coat 6 which is rich in moisture resistance, high in temperature and excellent in insulation. (6) The rectangular substrate 1 formed as described above is cut to a size of a standard value of a square chip resistor so that it can be mounted on an automatic mounting machine. (7) Copper is vapor-deposited at a predetermined position on the cutting end surface to form the first electrode 3, the second electrode 4, and the third electrode 5. (8) A variable temperature resistor mounted on the surfaces of the first electrode 3, the second electrode 4 and the third electrode 5 to ensure surface mounting and to be mounted on the second electrode 4 and the third electrode 5. Solder coating is applied to ensure that the body 7 is soldered. (9) The present invention, which is a chip-shaped rectangular substrate, is securely surface-mounted on a substrate by an automatic mounting machine or the like utilizing the surface mounting technology of a chip resistor. The present invention is constructed as described above.
It is a chip-type attenuator that is extremely compact, easy to manufacture and suitable for mass production, and can be surface-mounted very easily using the surface-mounting technology of chip resistors. Since the electrodes are formed in a U-shape extending over the upper surface, the side surface, and the lower surface, contact reliability is high. Further, the present invention can be easily manufactured in accordance with the output characteristics of the semiconductor used, and a highly practical chip capable of obtaining a constant output by compensating for an increase or decrease due to the ambient temperature of the output element. Type temperature variable attenuator. Further, as a means for increasing the amount of attenuation in accordance with a change in the ambient temperature, it is only necessary to externally attach a chip-type variable resistor to a predetermined chip-type attenuator. In addition, a chip-type variable temperature attenuator which can be designed to be small in size and can be easily mounted on a surface becomes extremely practical.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the present embodiment as viewed from the front side. FIG. 2 is a perspective view of the embodiment as viewed from the rear side. FIG. 3 is a plan view of the present embodiment. FIG. 4 is a bottom view of the present embodiment. FIG. 5 is an equivalent circuit diagram of the present embodiment. FIG. 6 is an explanatory diagram before surface mounting on a substrate of the present embodiment. FIG. 7 is an explanatory diagram after mounting, which is surface-mounted on a substrate according to the present embodiment. FIG. 8 is a characteristic graph showing a negative gain according to the present embodiment. FIG. 9 is an operation explanatory diagram and a characteristic graph showing the temperature compensation of the gain of the present embodiment. [Description of Signs] 1 Rectangular substrate 2 Metal thin film resistor 3 First electrode 4 Second electrode 5 Third electrode 6 Protective coat 7 Chip type temperature variable resistor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Inoue 537 Suzawa, Aomi-cho, Nishikubiki-gun, Niigata Pref. JP-A-5-258924 (JP, A) JP-A-4-117013 (JP, A) JP-A-3-115405 (JP, U) JP-A-4-29227 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H01C 7/04 H01C 1/02 H01C 7/00 H01C 13/02 H03H 7/24

Claims (1)

(57) [Claim 1] A metal thin film resistor is formed substantially at the center of the upper surface of a rectangular substrate, and the metal thin film is formed on one side of the rectangular substrate so as to have a U-shaped cross section extending over the upper and lower surfaces. Forming a first electrode in contact with one end of the resistor body, the cross-sectional U-shaped cross over the upper surface, the side surface, and the lower surface in the same manner on both side corners opposite to the first electrode of this rectangular substrate, and Forming a second electrode and a third electrode that are in contact with the other corners of the metal thin-film resistor, respectively, and covering the metal thin-film resistor with a protective coat for blocking outside air;
A chip-type variable temperature attenuator, wherein a block-shaped chip-type variable temperature resistor whose external resistance changes according to a change in ambient temperature is externally provided between the second electrode and the third electrode.