JP5846866B2 - High frequency switch - Google Patents

Description

  The present invention mainly relates to a high frequency switch used in a VHF band, a UHF band, a microwave band, and a millimeter wave band.

  In the conventional high-frequency switch, when the field effect transistor constituting the high-frequency switch is in an on state, the drain electrode and the source electrode are connected via a resistance (Ron: hereinafter referred to as on-resistance) inside the semiconductor. Pass through, and in the off state, the drain-source capacitance (Coff: hereinafter referred to as off-capacitance) can be seen, so that the input signal is cut off. This is because the impedance of the off-capacitance Coff is represented by 1 / jωCoff (ω is an angular frequency), and the impedance increases as the off-capacitance Coff is small. Here, the cutoff amount of the input signal is referred to as isolation of the high frequency switch (see Non-Patent Document 1 below).

Monolithic microwave integrated circuit, 6.1.2 switching function, pp. 167, Masayoshi Aikawa, Takashi Ohira, Tsuneo Tokuman, Tetsuo Hirota, Masahiro Muraguchi, The Institute of Electronics, Information and Communication Engineers, May 20, 1998.

Since the conventional high-frequency switch is configured as described above, the on-resistance Ron and the off-capacitance Coff are set to reduce switch loss in the on-state and to ensure switch isolation in the off-state. It is required to be as small as possible.
However, in general, the on-resistance Ron is inversely proportional to the gate width of the field effect transistor, and the off-capacitance Coff is proportional to the gate width.
Therefore, the two are in a trade-off relationship, and there is a problem that when the on-resistance Ron is reduced in order to reduce the loss of the switch, the off-capacitance Coff increases and the isolation of the switch is deteriorated.

  The present invention has been made to solve the above-described problems, and obtains a high-frequency switch that ensures a sufficient amount of isolation even if the resistance in the ON state is reduced in order to reduce the passage loss. For the purpose.

The high-frequency switch according to the present invention converts the input signal into a differential signal and outputs it from the first and second distribution terminals, the first signal conversion circuit having the isolation terminal grounded via a resistor, A first switching element having a first electrode connected to the distribution terminal of the first switching element and turning on or off between the first electrode and the second electrode according to a control signal applied to the control electrode; A second switching element having a first electrode connected to the second distribution terminal and turning on or off between the first electrode and the second electrode in accordance with a control signal applied to the control electrode Are connected between the first electrode of the first switching element and the second electrode of the second switching element, and the first electrode and the second electrode when the first and second switching elements are off A first capacitor having a capacitance between the first electrode and The first electrode and the second electrode connected between the second electrode of the first switching element and the first electrode of the second switching element, and when the first and second switching elements are in the OFF state And a second composite terminal connected to the second electrode of the second switching element and a second composite terminal connected to the second electrode of the first switching element And a second signal conversion circuit in which a differential signal input from the first and second combined terminals is combined and output, and an isolation terminal is grounded via a resistor. The switching element and the second switching element are integrally formed on the same wafer, and the first capacitor is arranged below the first electrode of the first switching element and below the second electrode of the second switching element. Ion implantation, they A first parallel plate capacitor formed by isolation implantation performed between the first electrode and the second electrode, and the second capacitor is a second electrode of the first switching element. A second electrode formed by ion implantation performed below and under the first electrode of the second switching element, and isolation implantation performed between the second electrode and the first electrode. It is constituted by a parallel plate capacitor . In the high-frequency switch of the present invention, the electrodes of the first switching element and the second switching element are arranged in a direction perpendicular to the finger direction, and alternately between the first switching element and the second switching element. It is characterized by the arrangement.

  According to the present invention, the first and second capacitors can cancel the capacitance between the first electrode and the second electrode when the first and second switching elements are in the OFF state. It can be greatly improved. Therefore, there is an effect that a sufficient amount of isolation can be ensured even if the resistance when the first and second switching elements are turned on is reduced in order to reduce the passage loss.

It is a circuit diagram which shows the high frequency switch by Embodiment 1 of this invention. It is an equivalent circuit diagram which shows the operating principle of a high frequency switch. It is an equivalent circuit diagram which shows the operating principle of the OFF state of a high frequency switch. It is an equivalent circuit diagram which shows the operation principle at the time of setting Cc = Coff of a high frequency switch. It is an equivalent circuit diagram which shows the operating principle of the ON state of a high frequency switch. It is a characteristic view which shows the passage loss of the ON state of a high frequency switch. It is a characteristic view which shows the isolation of the OFF state of a high frequency switch. It is a circuit diagram which shows the high frequency switch by Embodiment 2 of this invention. It is a circuit diagram which shows the other high frequency switch by Embodiment 2 of this invention. It is a circuit diagram which shows the high frequency switch by Embodiment 3 of this invention. It is sectional drawing which shows the arrow view detail of a high frequency switch. It is a circuit diagram which shows the high frequency switch by Embodiment 4 of this invention. It is sectional drawing which shows the arrow view detail of a high frequency switch. It is a circuit diagram which shows the high frequency switch by Embodiment 5 of this invention. It is a circuit diagram which shows the high frequency switch by Embodiment 6 of this invention.

Embodiment 1 FIG.
1 is a circuit diagram showing a high-frequency switch according to Embodiment 1 of the present invention.
In the figure, a 180 ° hybrid (first signal conversion circuit) 2 converts an input signal from the input terminal 1 into a differential signal and outputs it from the distribution terminals 3a and 3b. The isolation terminal 3 c of the 180 ° hybrid 2 is grounded through the resistor 4.

  A field effect transistor (FET: Field Effect Transistor, first switching element, hereinafter simply referred to as a transistor) 5a has a drain electrode (first electrode) D connected to a distribution terminal 3a and a resistance from a control signal input terminal 6a. The drain electrode D and the source electrode (second electrode) S are turned on or off according to a control signal applied to the gate electrode (control electrode) G through 7a.

  Similarly, in the transistor (second switching element) 5b, the drain electrode D is connected to the distribution terminal 3b, and the drain electrode D according to the control signal applied to the gate electrode G from the control signal input terminal 6b through the resistor 7b. And the source electrode S are turned on or off.

  The cross-coupled capacitor (first capacitor) 8a is connected between the drain electrode D of the transistor 5a and the source electrode S of the transistor 5b, and the capacitance Cc is the drain-source capacitance Coff when the transistors 5a and 5b are in the off state. Have

  The cross-coupled capacitor (second capacitor) 8b is connected between the source electrode S of the transistor 5a and the drain electrode D of the transistor 5b, and the capacitance Cc is the drain-source capacitance Coff when the transistors 5a and 5b are in the off state. Have

  The 180 ° hybrid (second signal conversion circuit) 9 has a synthesis terminal 10a connected to the source electrode S of the transistor 5a and a synthesis terminal 10b connected to the source electrode S of the transistor 5b, and inputs from the synthesis terminals 10a and 10b. The combined differential signals are combined and output from the output terminal 12. The isolation terminal 10 c of the 180 ° hybrid 9 is grounded through the resistor 11.

Next, the operation will be described.
FIG. 2 is an equivalent circuit diagram showing the operating principle of the high-frequency switch according to Embodiment 1 of the present invention. As shown in FIG. 1, input signals are differentially input to the transistors, and the capacitors connected between the transistors are so-called cross-coupled. With this configuration, the off-capacitance Coff that substantially determines the isolation of the switch can be canceled, and the isolation of the switch can be greatly improved.

The principle will be described below.
The isolation is expressed by the following formula (1) and is a parameter that greatly depends on Y ₁₂ .

Here, S ₁₂ is 12 components of S parameter (scattering matrix) (insertion loss from terminal 1 to terminal 2), Y ₁₁ is 11 components of Y parameter (admittance matrix), Y ₁₂ is 12 components of Y parameter, Y ₂₁ is the 21 component of the Y parameter, and Y ₂₂ is the 22 component of the Y parameter.
As can be seen from Equation (1), the smaller the absolute value of Y ₁₂ , the higher the isolation. When the input current I ₁ from the terminal 1 is obtained in order to obtain Y ₁₂ , the following equation (2) is obtained.

Here, v ₁₊ is the input voltage (normal phase), v ₂₊ is the output voltage (normal phase), v ₂₋ is the output voltage (reverse phase), and v ₁₊ = v _1, v ₂₊ = v ₂ = −v ₂₋ .
Y ₁₂ is determined by the ratio of the current on terminal 1 (corresponding to I ₁ ) and the input voltage (corresponding to v ₂₊ ) when terminal 1 is grounded, and is expressed by the following equation (3). The

As can be seen from this equation (3), if Cc = Coff, Y ₁₂ = 0, and the isolation of the switch can be made infinite in principle from equation (3).
FIG. 3 shows an equivalent circuit in the OFF state of the switch, and FIG. 4 shows an equivalent circuit when Cc = Coff. By loading the capacitor Cc, the off-capacitance Coff of the transistor can be canceled. Thereby, the isolation of the switch can be improved.

  On the other hand, FIG. 5 shows an equivalent circuit in the ON state of the switch. Therefore, when Ron << 1 / jωCoff holds, there is almost no influence of the capacitance Cc, so only the on-resistance Ron of the switch can be seen, and the passing loss is almost the same as when there is no capacitance Cc.

  FIG. 6 shows the calculation result of the passage loss in the on state of the switch, and FIG. 7 shows the calculation result of the isolation in the off state of the switch. The dotted line is the calculation result of the switch having the conventional configuration, and the solid line is the calculation result of the first embodiment. According to the configuration of the first embodiment, it can be seen that the on-state loss is not increased and the isolation can be greatly improved from −20 dB to −50 dB. In the calculation, values of Ron = 5 [Ω · mm] and Coff = 0.2 [pF / mm] were used.

Next, the operation of the high frequency switch shown in FIG. 1 will be described.
An input signal from the input terminal 1 is converted into a differential signal having a phase difference of 180 ° between the distribution terminals 3a and 3b by the 180 ° hybrid 2 and input to the transistors 5a and 5b.
The transistors 5a and 5b are turned on when a control signal equal to or higher than the pinch-off voltage is applied to the control signal input terminals 6a and 6b. Even when the transistors 5a and 5b are in the on state, the on-resistance Ron is generated. However, since this on-resistance Ron is small, the differential signal passes between the drain electrode D and the source electrode S of the transistors 5a and 5b. .
In the 180 ° hybrid 9, differential signals having a phase difference of 180 ° input from the combined terminals 10 a and 10 b are in phase, combined, and output from the output terminal 12.

On the other hand, the transistors 5a and 5b are turned off when a control signal equal to or lower than the pinch-off voltage is applied to the control signal input terminals 6a and 6b. When the transistors 5a and 5b are off, an off capacitance Coff is generated.
However, since the off-capacitance Coff of the transistors 5a and 5b is canceled by the capacitance Cc of the cross-couple capacitors 8a and 8b, the transistors 5a and 5b totally reflect the differential signal and do not pass through the 180 ° hybrid 9 side. The totally reflected reflected power is absorbed by the resistor 4 via the isolation terminal 3 c of the 180 ° hybrid 2.

  As described above, according to the first embodiment, the cross-coupled capacitors 8a and 8b having the same capacitance Cc as the off-capacitance Coff of the transistors 5a and 5b are provided. Since the off-capacitance of 5b can be canceled, the isolation can be greatly improved. Therefore, even if the on-resistance Ron of the transistors 5a and 5b is reduced in order to reduce the passage loss, a sufficient amount of isolation can be ensured.

  In the first embodiment, an FET is applied as the switching element. However, a bipolar transistor (HBT: Heterojunction Bipolar Transistor) may be applied. Further, a PIN diode, a varactor diode, or a MEMS (micro Electro Mechanical Systems) switch may be applied.

In the first embodiment, the 180 ° hybrids 2 and 9 are applied as the signal conversion circuit. However, a balun (Balance: balanced-unbalanced converter) may be applied.
When the balun is applied, the distribution terminals 3a and 3b or the combination terminals 10a and 10b are provided on the balanced terminal side of the balun, and the input terminal 1, the isolation terminal 3c or the output terminal 12, and the isolation terminal 10c are provided on the unbalanced terminal side. Just do it.

Embodiment 2. FIG.
FIG. 8 is a circuit diagram showing a high frequency switch according to Embodiment 2 of the present invention.
In the figure, transistors 5a and 5b are formed on the same wafer.
In the transistor 5a, the drain electrode 5a-1, the gate electrode 5a-2, and the source electrode 5a-3 are formed. Similarly, in the transistor 5b, the drain electrode 5b-1, the gate electrode 5b-2, and the source electrode 5b- 3 is formed.

The gate electrode 5a-2 of the transistor 5a and the gate electrode 5b-2 of the transistor 5b are connected by a wiring 21.
The cross-coupled capacitor 22a is provided between the drain electrode 5a-1 of the transistor 5a and the source electrode 5b-3 of the transistor 5b, which are opposed to each other, and is formed by a MIM (Metal Insulator Metal) capacitor.
Similarly, the cross-coupled capacitor 22b is provided between the source electrode 5a-3 of the transistor 5a and the drain electrode 5b-1 of the transistor 5b that are arranged to face each other, and is formed by an MIM capacitor.
About another structure, it is the same as Embodiment 1, the same code | symbol is attached | subjected to the same structure and the overlapping description is abbreviate | omitted.

  As described above, according to the second embodiment, the transistors 5a and 5b are formed on the same wafer, and the cross-coupled capacitor 22a is disposed between the drain electrode 5a-1 and the source electrode 5b-3 disposed so as to face each other. The cross-coupled capacitor 22b is formed by the MIM capacitor provided between the source electrode 5a-3 and the drain electrode 5b-1 that are arranged to face each other, so that the cross-coupled capacitors 22a and 22b are formed. Can be shortened, parasitic inductance generated in the wiring can be reduced, and the high-frequency switch can be increased in frequency and size.

  Further, since the gate electrode 5a-2 and the gate electrode 5b-2 are connected by the wiring 21, it is only necessary to provide the resistor 7a and the control terminal input terminal 6a in one gate electrode 5a-2. Wiring can be reduced.

In addition, you may comprise as shown in FIG. In the figure, the difference from FIG. 8 is that the wiring 21 is deleted and the gate electrode 5b-2 is provided with a resistor 7b and a control signal input terminal 6b.
With this configuration, it is possible to maintain circuit symmetry regarding the transistors 5a and 5b and the cross-coupled capacitors 22a and 22b, and to prevent characteristic deterioration due to circuit asymmetry.

Embodiment 3 FIG.
10 is a circuit diagram showing a high frequency switch according to Embodiment 3 of the present invention.
In the figure, the transistor 5 is integrally formed on the same wafer.
The gate electrode 5-2 is formed in common in the transistors 5.
The cross-coupled capacitor 31a is provided between the drain electrode 5a-1 and the source electrode 5b-3 arranged to face each other, and is formed by a parallel plate capacitor.
Similarly, the cross-coupled capacitor 31b is provided between the source electrode 5a-3 and the drain electrode 5b-1 disposed to face each other, and is formed by a parallel plate capacitor.
About another structure, it is the same as that of Embodiment 2, the same code | symbol is attached | subjected to the same structure, and the overlapping description is abbreviate | omitted.

11 is a cross-sectional view showing details of the inside of the semiconductor as seen from the direction of the arrow in FIG.
In the figure, ion implantation is performed below the drain electrode 5b-1 and the source electrode 5a-3 of the transistor 5, and isolation implantation is performed in order to insulate them.
Similarly, ion implantation is performed under the drain electrode 5a-1 and the source electrode 5b-3 of the transistor 5, and isolation implantation is performed in order to insulate them.
Where ion implantation is performed, Si (silicon) or the like is doped to increase the electron concentration, so that it can be regarded approximately as a metal. Therefore, a parallel plate capacitor is formed between the drain electrode and the source electrode. This parallel plate capacitor is used as the cross-coupled capacitors 31a and 31b.

  As described above, according to the third embodiment, since the transistor 5 is integrally formed on the same wafer and the cross-coupled capacitors 31a and 31b are formed of parallel plate capacitors, the transistor 5 is integrally formed. A part can be reduced in size. Further, the parasitic inductance generated in the MIM capacitor and the wiring connecting the capacitors can be reduced, and the high frequency switch can be increased in frequency and size.

Embodiment 4 FIG.
FIG. 12 is a circuit diagram showing a high frequency switch according to Embodiment 4 of the present invention.
In the figure, transistors 5a and 5b are integrally formed on the same wafer.
In the transistors 5a and 5b, the electrodes are arranged in a direction perpendicular to the finger direction, and the transistors 5a and 5b are alternately arranged.
The cross-coupled capacitor 41a is provided between the drain electrode 5a-1 of the adjacent transistor 5a and the source electrode 5b-3 of the transistor 5b, and is formed by a parallel plate capacitor.
Similarly, the cross-coupled capacitor 41b is provided between the source electrode 5a-3 of the adjacent transistor 5a and the drain electrode 5b-1 of the transistor 5b, and is formed by a parallel plate capacitor.
About another structure, it is the same as Embodiment 3, the same code | symbol is attached | subjected to the same structure, and the overlapping description is abbreviate | omitted.

FIG. 13 is a cross-sectional view showing details of the inside of the semiconductor viewed from the direction of the arrow in FIG.
In the figure, ion implantation is performed under the drain electrode 5a-1 of the transistor 5a and under the source electrode 5b-3 of the transistor 5b, and isolation implantation is performed to insulate them.
Similarly, ion implantation is performed under the drain electrode 5b-1 of the transistor 5b and under the source electrode 5a-3 of the transistor 5a, and isolation implantation is performed in order to insulate them.
Accordingly, as in the third embodiment, a parallel plate capacitor is formed between the drain electrode and the source electrode. This parallel plate capacitor is used as the cross-coupled capacitors 41a and 41b.

  As described above, according to the fourth embodiment, the transistors 5a and 5b are integrally formed on the same wafer, the electrodes of the transistors 5a and 5b are arranged in a direction perpendicular to the finger direction, and the transistors 5a and 5b are arranged. Since the transistors 5a and 5b are integrally formed, the transistor portion can be reduced in size. Further, the degree of freedom in layout of the transistors 5a and 5b can be improved.

  In the fourth embodiment, the cross couple capacitors 41a and 41b are formed of parallel plate capacitors as shown in the third embodiment. However, as shown in the second embodiment, the cross couple capacitors 41a and 41b are formed of MIM capacitors. May be.

Embodiment 5 FIG.
FIG. 14 is a circuit diagram showing a high frequency switch according to Embodiment 5 of the present invention.
In the figure, a balun (first signal conversion circuit) 51 converts an input signal from the input terminal 1 into a differential signal and outputs it from the distribution terminals 3a and 3b.
In the balun 51, one end of the coupled line 51 a-1 is connected to the input terminal 1. One end of the coupled line 51b-1 is connected to the other end of the coupled line 51a-1. The coupled line 51a-2 is arranged in parallel to the coupled line 51a-1, and has one end connected to the ground and the other end connected to the distribution terminal 3a. The coupled line 51b-2 is arranged in parallel to the coupled line 51b-1, and has one end connected to the distribution terminal 3b and the other end grounded to the ground. The line lengths of the coupled lines 51a-1, 51b-1, 51a-2, and 51b-2 have approximately a quarter wavelength of the used frequency.

The balun (second signal conversion circuit) 52 synthesizes the differential signals input from the combining terminals 10 a and 10 b and outputs the combined signals from the output terminal 12.
In the balun 52, one end of the coupled line 52a-1 is grounded to the ground, and the other end is connected to the composite terminal 10a. The coupling line 52b-1 has one end connected to the composite terminal 10b and the other end grounded to the ground. The coupled line 52 a-2 is arranged in parallel to the coupled line 52 a-1 and one end is connected to the output terminal 12. The coupled line 52b-2 is arranged in parallel to the coupled line 52b-1, and one end is connected to the other end of the coupled line 52a-2. The line lengths of the coupled lines 52a-1, 52b-1, 52a-2, and 52b-2 have approximately a quarter wavelength of the used frequency.
About another structure, it is the same as Embodiment 1, the same code | symbol is attached | subjected to the same structure and the overlapping description is abbreviate | omitted.

  As described above, according to the fifth embodiment, since the baluns 51 and 52 are configured by so-called merchant baluns that use electromagnetic coupling between coupled lines, the entire high-frequency switch can be configured by a planar circuit. , MMIC (Monolithic Microwave Integrated Circuits) can be easily realized, and miniaturization and uniform production are possible by using MMIC.

Embodiment 6 FIG.
FIG. 15 is a circuit diagram showing a high-frequency switch according to Embodiment 6 of the present invention.
In the figure, a balun (first signal conversion circuit) 61 converts an input signal from the input terminal 1 into a differential signal and outputs it from the distribution terminals 3a and 3b.
In the balun 61, the grounded transistor 61a has a drain electrode D connected to the input terminal 1 and a source electrode S connected to the distribution terminal 3a. In the common source transistor 61b, the gate electrode G is connected to the input terminal 1, and the drain electrode D is connected to the distribution terminal 3b.

The balun (second signal conversion circuit) 62 combines the differential signals input from the combining terminals 10a and 10b and outputs the combined signal from the output terminal 12.
In the balun 62, the grounded gate transistor 62 a has a drain electrode D connected to the composite terminal 10 a and a source electrode S connected to the output terminal 12. In the source terminal grounded transistor 62b, the drain electrode D is connected to the composite terminal 10b, and the gate electrode G is connected to the output terminal 12.
About another structure, it is the same as Embodiment 1, the same code | symbol is attached | subjected to the same structure and the overlapping description is abbreviate | omitted.

  In the sixth embodiment, the baluns 61 and 62 are configured by a combination of a grounded gate transistor and a grounded source terminal transistor, the grounded gate transistor is a positive phase amplifier, and the grounded source transistor is a negative phase amplifier. Using the characteristics, create a differential signal.

  As described above, according to the sixth embodiment, since the baluns 61 and 62 are configured by the combination of the gate grounded transistor and the source terminal grounded transistor, the entire high frequency switch can basically be configured by the transistor. Further, the line and the like are not necessary, and the size can be further reduced.

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

  1 input terminal, 2 180 ° hybrid (first signal conversion circuit), 3a, 3b distribution terminal, 3c, 10c isolation terminal, 4, 7a, 7b, 11 resistance, 5, 5a transistor (first switching element) 5, 5b transistor (second switching element), 5a-1, 5b-1 drain electrode, 5-2, 5a-2, 5b-2 gate electrode, 5a-3, 5b-3 source electrode, 6a, 6b Control signal input terminal, 8a, 22a, 31a, 41a Cross-coupled capacitor (first capacitor), 8b, 22b, 31b, 41b Cross-coupled capacitor (second capacitor), 9 180 ° hybrid (second signal conversion circuit) ) 10a, 10b composite terminal, 12 output terminal, 21 wiring, 51, 61 balun (first signal conversion circuit), 51a-1, 51a-2, 51b-1, 51b-2, 52a-1, 52a-2, 52b-1, 52b-2 coupling line, 52, 62 balun (second signal conversion circuit), 61a, 62a Common gate transistor, 61b, 62b Common source transistor.

Claims (2)

A first signal conversion circuit in which an input signal is converted into a differential signal and output from the first and second distribution terminals, and an isolation terminal is grounded via a resistor;
A first switching terminal configured to connect a first electrode to the first distribution terminal and to turn on or off between the first electrode and the second electrode according to a control signal applied to the control electrode; Elements,
A first switching is connected to the second distribution terminal, and the second switching is performed between the first electrode and the second electrode according to a control signal applied to the control electrode. Elements,
A first electrode connected to a first electrode of the first switching element and a second electrode of the second switching element; the first electrode when the first and second switching elements are off; A first capacitor having a capacitance between the second electrode;
A first electrode connected between a second electrode of the first switching element and a first electrode of the second switching element; and when the first and second switching elements are in an off state; A second capacitor having a capacitance between the second electrode;
A first composite terminal is connected to the second electrode of the first switching element, and a second composite terminal is connected to the second electrode of the second switching element. A differential signal input from the terminal is combined and output, and the isolation terminal includes a second signal conversion circuit grounded via a resistor,
The aforementioned first switching element and the second switching element is integrally formed on the same wafer,
Said first capacitor,
Ion implantation performed under the first electrode of the first switching element and under the second electrode of the second switching element, and between the first electrode and the second electrode. Constituted by a first parallel plate capacitor formed by isolated isolation injection,
Said second capacitor,
Ion implantation performed under the second electrode of the first switching element and under the first electrode of the second switching element, and between the second electrode and the first electrode. high frequency switch you wherein second that is constituted by parallel plate capacitor formed by the Broken isolation implantation. A first signal conversion circuit in which an input signal is converted into a differential signal and output from the first and second distribution terminals, and an isolation terminal is grounded via a resistor;
A first switching terminal configured to connect a first electrode to the first distribution terminal and to turn on or off between the first electrode and the second electrode according to a control signal applied to the control electrode; Elements,
A first switching is connected to the second distribution terminal, and the second switching is performed between the first electrode and the second electrode according to a control signal applied to the control electrode. Elements,
A first electrode connected to a first electrode of the first switching element and a second electrode of the second switching element; the first electrode when the first and second switching elements are off; A first capacitor having a capacitance between the second electrode;
A first electrode connected between a second electrode of the first switching element and a first electrode of the second switching element; and when the first and second switching elements are in an off state; A second capacitor having a capacitance between the second electrode;
A first composite terminal is connected to the second electrode of the first switching element, and a second composite terminal is connected to the second electrode of the second switching element. A differential signal input from the terminal is combined and output, and the isolation terminal includes a second signal conversion circuit grounded via a resistor,
The first switching element and the second switching element are formed on the same wafer,
The first capacitor is
A first Metal-Insulator-Metal capacitor connected between the first electrode of the first switching element and the second electrode of the second transistor;
The second capacitor is
A second Metal-Insulator-Metal capacitor connected between the second electrode of the first switching element and the first electrode of the second switching element;
With each electrode are arranged in a direction perpendicular to the finger direction of the first switching element and the second switching element, that in the first switching element and the second switching elements are arranged alternately high-frequency switch it said.

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