JP5611110B2 - High frequency amplifier - Google Patents

Description

  The present invention relates to a high frequency amplifier.

  A configuration of a conventional high-frequency amplifier will be described with reference to FIG. As shown in FIG. 1, the conventional high-frequency amplifier includes a plurality of transistor cells 1 and drain / source fingers 22 inside each transistor cell 1. The transistor cells 1 are arranged on a straight line (on the line indicated by the dotted line 3 in FIG. 1) at a constant interval l. In the conventional high-frequency amplifier, the heat radiation performance is improved by increasing the interval l between the transistor cells 1 which are heat generating portions (see, for example, Non-Patent Document 1).

S. Masuda et al., “Over 10W C-Ku Band GaN MMIC Non-uniform Distributed Power Amplifier with Broadband Couplers,” 2010 IEEE MTT Symposium, pp.1388-1391, May, 2010.

  However, in the conventional high frequency amplifier, since the center of the transistor cell 1 is arranged on the same line, the diffusion of heat from the high frequency amplifier to the lower portion of the high frequency amplifier is changed from the transistor cell 1 of the high frequency amplifier in FIG. In the positive direction of the z-axis, the heat flow between adjacent transistor cells 1 collides at a distance of half of the interval l, and there is a problem that the heat flow interference range is wide and the thermal resistance increases and the heat dissipation performance of the entire high-frequency amplifier deteriorates. there were.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-frequency amplifier in which the thermal resistance is lowered and the heat radiation performance of the entire high-frequency amplifier is improved.

In the high-frequency amplifier according to the present invention, the center of the transistor is arranged such that the heat flow passage areas that specify the heat flow passage areas of the two adjacent transistors among the plurality of transistors arranged on a plane overlap each other. from the x-axis direction which is the arrangement direction of the plurality of transistors Rashi not the y-axis direction orthogonal to the x-axis direction and it is characterized in that a respective transistor.

  According to this invention, since the center of the x-axis direction is shifted in the y-axis direction, the transistor can provide a high-frequency amplifier in which the thermal resistance is lowered and the heat dissipation performance of the entire high-frequency amplifier is improved.

It is a circuit diagram of the conventional high frequency amplifier. 1 is a circuit diagram of a high frequency amplifier according to Embodiment 1 of the present invention. FIG. It is a figure for demonstrating the effect of the high frequency amplifier of FIG. It is a figure for demonstrating the effect of the high frequency amplifier of FIG. It is a circuit diagram of the high frequency amplifier which concerns on Embodiment 2 of this invention. It is a circuit diagram of the conventional two-stage high frequency amplifier. It is a figure for demonstrating the effect of the high frequency amplifier of FIG. It is a circuit diagram of the high frequency amplifier which concerns on Embodiment 3 of this invention. It is a figure for demonstrating the effect of the high frequency amplifier of FIG.

Embodiment 1 FIG.
FIG. 2 is a circuit diagram of the high frequency amplifier according to Embodiment 1 of the present invention. In FIG. 2, 1a to 1g are transistor cells (transistors), 2 is a peripheral circuit, and 10 is a high-frequency amplifier.

For all the transistor cells 1a-1g, the centers in the x-axis direction of the two adjacent transistor cells (eg, transistor cells 1a and 1b, transistor cells 1b and 1c, etc.) are shifted in the y-axis direction alternately. ing.
Here, staggering means that transistor cells (for example, 1a) shifted downward and transistor cells (for example, 1b) shifted upward are alternately arranged.

  Specifically, if the transistor cells 1a-1g are 1a, 1b,..., 1g from the left in FIG. 2, the centers of 1a, 1c, 1e, 1g are positioned on the line indicated by the dotted line D in FIG. The centers of 1b, 1d, and 1f are located on the line indicated by the dotted line E that is above the line indicated by the dotted line D in FIG.

  In the description of this embodiment, a transistor cell is used for description, but the transistor cells 1a to 1g may be formed of one transistor. The same applies to the following description.

  The description is given using an example in which there is a line indicated by a dotted line E above the line indicated by a dotted line D in FIG. 2, but there is a line indicated by a dotted line D above the line indicated by a dotted line E in FIG. May be.

  In the description of the first embodiment, the case where the number of transistor cells 1a-1g is seven is described as an example, but it is not necessary to be seven.

式（１）において、χは熱が伝達する媒質（半導体内部あるいは放熱器など）の熱伝導率、ｈ１は計算する範囲のｚ軸方向における上辺、ｈ２は計算する範囲のｚ軸方向における下辺、Ｓ（ｚ）は、あるｚ（ｈ１＜ｚ＜ｈ２）についてのｘ−ｙ平面上において熱流の通過する面積である。式（１）より、熱抵抗は面積が大きいほど小さくなる、言い換えると放熱面積が大きいほど放熱性能が高いと言える。 Next, the heat dissipation performance of the high frequency amplifier 10 according to the first embodiment will be described.
The magnitude of thermal resistance can be used as an index of heat dissipation performance. The thermal resistance Rth can be calculated using equation (1).

In Equation (1), χ is the thermal conductivity of a medium (such as the inside of a semiconductor or a radiator) through which heat is transferred, h1 is the upper side in the z-axis direction of the calculation range, h2 is the lower side in the z-axis direction of the calculation range, S (z) is an area through which the heat flow passes on the xy plane for a certain z (h1 <z <h2). From the equation (1), it can be said that the heat resistance is smaller as the area is larger, in other words, the heat radiation performance is higher as the heat radiation area is larger.

Several models have been proposed for S (z). A model used in the following description will be described with reference to FIG.
The heat flow diffuses for the distance transmitted. When a rectangle having a side length of (l × m) (hatched portion in FIG. 3) is a heat radiating surface and a heat flow transfer distance in the z-axis direction is h, S (z) is {(l + 2h ) × (m + 2h)} rectangle (the rectangle with the larger area in FIG. 3) minus the rectangle (l × m) (the hatched portion in FIG. 3). In the following discussion, S (z) is calculated using this model.

  The conventional high-frequency amplifier shown in FIG. 1 and the high-frequency amplifier 10 according to the first embodiment will be compared based on the heat flow passage area. 1 and 2, each transistor cell 1 is a heating element (heating surface).

  FIG. 4A is a diagram showing a heat flow passage area in a cut surface parallel to the xy plane at a distance of 0.2 mm in the z-axis direction from the heat generation surface in the conventional high-frequency amplifier shown in FIG. It is.

  FIG. 4B shows the heat flow passage area on the cut plane parallel to the xy plane at a distance of 0.2 mm in the z-axis direction from the heat generation surface for the high-frequency amplifier 10 according to the first embodiment. FIG.

Parameters for calculating S (0.2) in FIGS. 4A and 4B are shown in FIG. As a result of calculating S (0.2) based on the parameters of FIG. 4C, S (0.2) of the high-frequency amplifier 10 according to the first embodiment is 1.865 mm ² , which is shown in FIG. S (0.2) in the conventional high-frequency amplifier was 1.625 mm ² . The S (0.2) of the high-frequency amplifier 10 according to the first embodiment is about 15% larger than S (0.2) in the conventional high-frequency amplifier. For this reason, it can be said that the high frequency amplifier 10 has improved heat dissipation performance.

For the high-frequency amplifier 10 according to the first embodiment and the conventional high-frequency amplifier shown in FIG. 1, a material and its thickness are defined in the z-axis direction, and a more practical amount of improvement in heat dissipation performance is calculated. FIG. 4D shows the calculation conditions for the material. The size of each material in the x-axis and y-axis directions is infinite.
When the heat dissipation performance, that is, the thermal resistance Rth is calculated under these conditions, the thermal resistance in the high-frequency amplifier 10 according to the first embodiment is 2.6 [K / W], and the thermal resistance value 2 of the conventional high-frequency amplifier is 2 As a result, the thermal resistance was about 10% smaller than that of .88 [K / W].

  Assuming the performance of the semiconductor device and the high frequency amplifier in FIG. 4 (e) and comparing them at room temperature, the high frequency amplifier 10 according to the first embodiment has a temperature of the semiconductor device of 16 degrees as compared with the conventional high frequency amplifier. Low and 0.64 dB gain is high.

From the above, the heat radiation performance can be improved by the high-frequency amplifier 10 according to the first embodiment.
At the same time, since the heat dissipation performance is good, the temperature of the device can be lowered, which is advantageous from the viewpoint of the reliability of the semiconductor device. Further, the gain of the high-frequency amplifier 10 can be improved due to the low temperature. Moreover, the efficiency of the high frequency amplifier 10 can be improved by improving the gain of the high frequency amplifier 10. At the same time, by improving the gain of the high-frequency amplifier 10, the output power required for the high-frequency amplifier 10 in the driver stage connected to the front stage of the high-frequency amplifier 10 can be reduced, which is advantageous for downsizing and cost reduction of the system. . In general, the output power of a transistor is reduced under high thermal conditions as well as the gain, so that the output power can be improved.

  In the first embodiment, the distributed amplifier has been described as an example, but the same effect can be obtained even with a distribution-synthesis amplifier.

  In FIG. 2, as an example of the high-frequency amplifier according to the first embodiment, for all the transistor cells 1a-1g, two adjacent transistor cells (1a and 1b, 1b and 1c, 1c and 1d, 1d and 1e are used. 1e and 1f and 1f and 1g) have been described as examples in which the centers in the x-axis direction are staggered in the y-axis direction. However, the present invention is not limited thereto, and at least two adjacent transistor cells (1a and 1f) 1b or 1b and 1c, etc.) can be obtained if the respective centers in the x-axis direction are shifted in the y-axis direction.

  As described above, the high-frequency amplifier 10 according to the first embodiment includes a plurality of transistor cells 1a-1g, and two adjacent transistor cells among the plurality of transistor cells 1a-1g arranged on the plane. The respective centers in the x-axis direction are configured to be shifted in the y-axis direction. Therefore, it is possible to provide the high frequency amplifier 10 in which the thermal resistance is lowered and the heat radiation performance of the entire high frequency amplifier 10 is improved.

  Further, according to the first embodiment, all the transistor cells 1a to 1g are configured such that the centers in the x-axis direction of the two adjacent transistor cells are staggered in the y-axis direction. Thus, it is possible to provide the high frequency amplifier 10 in which the thermal resistance is further reduced and the heat radiation performance of the entire high frequency amplifier 10 is further improved.

Embodiment 2. FIG.
Next, a high frequency amplifier 20 according to Embodiment 2 of the present invention will be described. FIG. 5 is a diagram showing a circuit configuration of the high-frequency amplifier 20 according to the second embodiment. In FIG. 5, 1a to 1f are transistor cells (transistors), 2 is a peripheral circuit, and 20 is a high-frequency amplifier.

  The high-frequency amplifier 20 has a two-stage configuration that is cascade-connected to each other, and includes transistor cells 1a, 1b, 1c, and 1d included in the upper stage of the two stages, and transistor cells 1e and 1f included in the lower stage of the two stages. Prepare.

Regarding the transistor cells 1a, 1b, 1c, and 1d included in the upper stage of the two stages, the respective centers in the x-axis direction of the two adjacent transistor cells (1a and 1b, 1b and 1c, and 1c and 1d) are y They are staggered in the axial direction.
More specifically, the positional relationship is such that transistor cells shifted upward and transistor cells shifted downward are alternately arranged.

In the example of FIG. 5, among the transistor cells 1a, 1b, 1c, and 1d included in the upper stage, the transistor cells 1a and 1c are located above and the transistor cells 1b and 1d are located below.
The transistor cells 1e and 1f included in the lower stage are positioned below the transistor cells (transistor cells 1a and 1c) arranged above the transistor cells 1a, 1b, 1c, and 1d included in the upper stage.

  Similar to the first embodiment, the high-frequency amplifier 20 according to the second embodiment is compared with the conventional high-frequency amplifier in terms of heat dissipation performance. Since the heat dissipation performance is better when the passage area S (z) of the heat flow is larger, this is also used as an index here.

  A conventional two-stage high-frequency amplifier for comparison is shown in FIG. 5 and 6, each transistor cell is a heating element (heating surface).

  FIG. 7A shows a heat flow passage area in a cut plane parallel to the xy plane at a distance of 0.2 mm in the z-axis direction from the heat generation surface for the high-frequency amplifier 20 according to the second embodiment. FIG.

  FIG. 7B is a diagram showing a heat flow passage area on a cut surface parallel to the xy plane at a distance of 0.2 mm in the z-axis direction from the heat generation surface for the conventional high-frequency amplifier shown in FIG. It is.

FIG. 7C shows parameters of the transistor cell 1 for calculating S (0.2) in FIGS. 7A and 7B. As a result of calculating S (0.2) based on the parameters of FIG. 7C, S (0.2) of the high-frequency amplifier 20 according to the second embodiment is 1.59 mm ² , which is shown in FIG. S (0.2) in the conventional high-frequency amplifier was 1.35 mm ² . The S (0.2) of the high frequency amplifier 20 according to the second embodiment is about 15% larger than S (0.2) in the conventional high frequency amplifier. For this reason, it can be said that the high-frequency amplifier 20 has improved heat dissipation performance.

  From the above, the heat radiation performance is improved by the high-frequency amplifier 20 according to the second embodiment. At the same time, as described in the first embodiment, gain, efficiency, output power, and the like can be improved.

In the second embodiment, the high-frequency amplifier 20 having a two-stage configuration has been described, but it may be configured by n stages (n is a natural number) connected in cascade.
In this case, with respect to the transistor cells included in at least one of the n stages, the centers in the x-axis direction of the two adjacent transistor cells may be alternately shifted in the y-axis direction.

  In the second embodiment, the distribution / synthesis type amplifier has been described as an example, but the same effect can be obtained even with a distributed type amplifier.

  As described above, the high-frequency amplifier 20 according to the second embodiment includes n (n is a natural number) stages connected in cascade, and is included in at least one of the n stages among the plurality of transistor cells 1a-1f. The transistor cells 1a to 1d are configured such that the centers in the x-axis direction of the two adjacent transistor cells are staggered in the y-axis direction. Therefore, it is possible to provide the high frequency amplifier 20 in which the thermal resistance is lowered and the heat radiation performance of the entire high frequency amplifier 20 is improved.

Embodiment 3 FIG.
Next, a high frequency amplifier 30 according to Embodiment 3 of the present invention will be described. FIG. 8 is a diagram showing a circuit configuration of the high-frequency amplifier 30 according to the third embodiment. In FIG. 8, 1 is a plurality of transistor cells, 2 is a plurality of peripheral circuits, and 30 is a high-frequency amplifier.

The high frequency amplifier 30 has a one-stage configuration.
The transistor cell 1 is arranged on a straight line. The angle formed by the direction of the straight line (the straight line indicated by the dotted line F in FIG. 8) in which the transistor cell 1 is arranged and the longitudinal direction of each transistor cell 1 is 90 degrees.

  The high frequency amplifier 30 can be obtained by rotating each transistor cell 1 clockwise by 90 degrees with respect to the high frequency amplifier shown in FIG.

  As in the first embodiment, the high-frequency amplifier 30 according to the third embodiment is compared with the conventional high-frequency amplifier in terms of heat dissipation performance. Since the heat dissipation performance is better when the passage area S (z) of the heat flow is larger, this is also used as an index here.

The calculation of the conventional high-frequency amplifier for comparison is the same as that in the first embodiment.
In FIG. 8, each transistor cell 1 is a heating element (heating surface).

  FIG. 9 is a diagram showing a heat flow passage area on a cut surface parallel to the xy plane at a position of a distance of 0.2 mm in the z-axis direction from the heat generation surface for the high-frequency amplifier 30 according to the third embodiment. .

FIG. 4C shows parameters of the transistor cell 1 for calculating S (0.2) in FIG. As a result of calculating S (0.2) based on the parameters of FIG. 4C, S (0.2) of the high-frequency amplifier 30 according to the third embodiment is 1.76 mm ² , which is shown in FIG. S (0.2) in the conventional high-frequency amplifier was 1.625 mm ² (described above). The S (0.2) of the high frequency amplifier 30 according to the third embodiment is about 8% larger than S (0.2) in the conventional high frequency amplifier. For this reason, it can be said that the high-frequency amplifier 30 has improved heat dissipation performance.

  From the above, the heat radiation performance is improved by the high-frequency amplifier 30 according to the third embodiment. At the same time, as described in the first embodiment, gain, efficiency, output power, and the like can be improved.

  The description of the high-frequency amplifier 30 according to the third embodiment has been made using an example in which the angle formed by the straight line direction in which the plurality of transistor cells 1 are arranged and the longitudinal direction of each transistor cell 1 is 90. However, the angle may be any of greater than 0 degrees and up to 90 degrees. Thereby, it is possible to obtain a similar effect.

  In the third embodiment, the distributed amplifier has been described as an example, but the same effect can be obtained even with a distribution-synthesis amplifier.

  As described above, the high-frequency amplifier 30 according to the third embodiment includes the plurality of transistor cells 1 arranged on a straight line, and the direction of the straight line in which the plurality of transistor cells 1 are arranged, and each of the plurality of transistor cells 1. The angle formed with the longitudinal direction of the transistor cell was configured to be any of over 0 degree and up to 90 degrees. Therefore, it is possible to provide the high frequency amplifier 30 in which the thermal resistance is reduced and the heat radiation performance of the entire high frequency amplifier 30 is improved.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1, 1a, 1b, 1c, 1d, 1e, 1f, 1g Transistor cell (transistor), 2 peripheral circuit, 10, 20, 30 high frequency amplifier, 22 drain source finger.

Claims (4)

In a high-frequency amplifier composed of a plurality of transistors,
The arrangement direction of the plurality of transistors is such that the centers of the transistors overlap so that the heat flow passage regions that specify the respective heat flow passage areas of the two adjacent transistors among the plurality of transistors arranged on a plane overlap each other. in it are the x-axis direction Rashi not the y-axis direction orthogonal to the x-axis direction, the high-frequency amplifier, characterized in that a respective said transistor. For all of the transistors, the centers of the x-axis direction in each of two transistors that are adjacent in that claim 1, wherein the wherein are offset alternately in the y-axis direction high-frequency amplifier. It is composed of n stages (n is a natural number) cascaded together,
Among the plurality of transistors, the transistors included in at least one stage of the n stages, that the center of the x-axis direction in each of two transistors that are adjacent are offset alternately in the y-axis direction The high-frequency amplifier according to claim 1. The direction of the straight line in which the plurality of transistors are arranged so that the heat flow passage regions that specify the heat flow passage areas of the adjacent transistors among the plurality of transistors arranged on a straight line overlap each other, high-frequency amplifier angle between the longitudinal direction of the respective transistors of the plurality of transistors, characterized in that a said transistor to be either up and 90 degrees greater than 0 degrees.

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