JP2009164482A - Balun resonator, semiconductor device, and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balun resonator which singly copes with input signals of a wide band. <P>SOLUTION: A first coil is formed by forming a small coil in a large coil formed in a plane shape so as to be the same plane as the large coil, and second and third coils are formed similarly and laminated. One side terminals of the respective coils are connected to a balanced terminal and an unbalanced terminal, the other side terminals are grounded, and thus the balun resonator is configured. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a balun resonator used for converting an electric signal in a balanced and unbalanced state, a semiconductor device using the balun resonator, and a receiving device.

  Conventionally, for example, a low noise amplifier circuit, a so-called LNA (Low Noise Amplifier) circuit for receiving a wideband radio signal from a VHF band (30 to 300 MHz) to a UHF band (300 to 3000 MHz) as used in television broadcasting. Is used. As an example of the LNA circuit, a circuit as shown in FIG. 18 is used. The LNA circuit shown in FIG. 18 is realized using a so-called balun resonator. The balun resonator is a balun that converts a balanced-unbalanced state of an electric signal and has a function of selecting a frequency in a desired band. The balun is called a balanced-unbalanced converter.

  In the LNA circuit shown in FIG. 18, the frequency band is divided into three in order to cope with a wideband frequency, and the circuit is configured independently for each frequency band. The frequency band of the first circuit is 550 to 900 MHz, the frequency band of the second circuit is 180 to 550 MHz, and the frequency band of the third circuit is 46 to 180 MHz. These first to third circuits are connected in parallel to the antenna 201. In FIG. 18, a portion surrounded by a wavy line, that is, a balun resonator and an inductor are external components, and the rest are mounted inside the IC.

  First, the configuration of the first circuit will be described. As shown in FIG. 18, the source (common terminal) of a transistor 202a made of, for example, a field-effect transistor (FET) is connected to the antenna 201. The transistor 202a functions as a switch. When an electric signal from the antenna 201 is input to the circuit, an appropriate voltage is applied to the gate (input terminal) to turn it on. The unbalanced terminal of the balun resonator 203a is connected to the drain (output terminal) of the transistor 202a. Similarly, the second circuit and the third circuit are provided with transistors 202b and 202c, respectively.

  An inductor 204a1, a variable capacitance element 205a, and a resistance element 206a are connected in parallel to the two balanced terminals of the balun resonator 203a. Further, an inductor 204a2 is connected in series between one end of the inductor 204a1 and one end of the variable capacitance element 205a, and an inductor 204a3 is connected in series between the other end of the inductor 204a1 and the other end of the variable capacitance element 205a. ing. Note that the inductors 204a2 and 204a3 are connected in series to the output of the balun resonator 203a, thereby matching the output of the balun resonator 203a with the RF (Radio Frequency) input from the antenna 201.

  These inductors 204a1 to 204a3, variable capacitance element 205a, and resistance element 206a constitute a filter 221a that passes an electric signal in a desired frequency band. A differential amplifier 207a is further connected to the output side of the filter 221a. On the output side of the differential amplifier 207a, a variable capacitance element 208a and an inductor 209a are connected in parallel to constitute a filter 222a.

  The reason why the filters 221a and 222a are connected to the input side and the output side of the differential amplifier 207a is to remove unnecessary electrical signals that cannot be sufficiently removed by one filter by using two filters. .

  In this first circuit, an LNA circuit corresponding to a desired frequency band (550 to 900 MHz) can be configured by adjusting the values of the inductors 204a1 to 204a3 and 209a and the variable capacitance elements 205a and 208a.

  The second circuit has the same configuration as the first circuit, and a filter that passes an electrical signal in a desired frequency band to the output side of the balun resonator 203b by the inductors 204b1 to 204b3, the variable capacitance element 205b, and the resistance element 206b. 221b is configured. A differential amplifier 207b is further connected to the output side of the filter 221b. On the output side of the differential amplifier 207b, a variable capacitance element 208b and an inductor 209b are connected in parallel to constitute a filter 222b.

  In the second circuit, an LNA circuit in a desired frequency band (180 to 550 MHz) can be configured by adjusting the values of the inductors 204b1 to 204b3 and 209b and the variable capacitance elements 205b and 208b.

  The third circuit has substantially the same configuration as the first circuit and the second circuit. In the third circuit, on the output side of the balun resonator 203c, a filter 221c that passes an electric signal in a desired frequency band is configured by the inductors 204c1 to 204c3, the variable capacitance element 205c, and the resistance element 206c. A differential amplifier 207c is further connected to the output side of the filter 221c. On the output side of the differential amplifier 207c, a variable capacitance element 208c and an inductor 209c are connected in parallel to constitute a filter 222c.

  Further, for the third circuit, in addition to the configuration of the first circuit or the second circuit, a filter 223c including variable capacitance elements 210c1, 210c2, 210c3 and an inductor 211 is connected to the output side of the filter 222c. Yes. By providing a large number of filters in this manner, it is possible to extract an electrical signal having a very narrow bandwidth with respect to the frequency band (46 to 180 MHz) of the LNA circuit, for example, with a bandwidth of 8 MHz.

  In the third circuit, by adjusting the values of the inductors 204c1 to 204c3, 209c, and 211c and the variable capacitance elements 205c, 208c, and 210c1 to 210c3, an LNA circuit of a desired frequency band (46 to 180 MHz) is configured. can do.

  FIG. 19 is a diagram showing a configuration of a module in which the conventional LNA circuit shown in FIG. 18 is mounted.

  In the conventional LNA circuit, as shown in FIG. 18, external components are used for the balun resonators 203a to 203c and inductors 204a1 to 204a3, 204b1 to 204b3, 204c1 to 204c3, 209a to 209c, and 211c surrounded by a broken line. Is done. Therefore, as shown in FIG. 19, one IC (Integrated Circuit) 301 for mounting, for example, an LNA circuit is installed on one mother substrate 300, and three balun resonators 203a to 203c and its balun resonance are arranged around the IC. Inductors 204a1 to 204a3, 204b1 to 204b3, 204c1 to 204c3, 209a to 209c, and 211c are installed corresponding to the installation positions of the devices 203a to 203c.

Further, there has been disclosed a microwave coupling line in which signal characteristics are not greatly deteriorated even when a positional deviation or the like occurs in two lines (see, for example, Patent Document 1).
JP 2004-32199 A

  In the configuration of the conventional LNA circuit, as described with reference to FIGS. 18 and 19, it is necessary to install a balun resonator and an inductor for each required frequency band. Therefore, a large substrate for installing a plurality of balun resonators is required, and there is a problem that a mounting area becomes large. Therefore, when a mother board, a module using the mother board, and the like are installed in a casing of a tuner device, for example, a television receiver, there is a problem that the layout is restricted and it is difficult to reduce the size.

  The present invention has been made in view of such a situation, and an object of the present invention is to enable a single balun resonator to cope with a broadband input signal.

  In order to solve the above-mentioned problems, the balun device of the present invention has one end connected to the balanced terminal, the other end grounded, a first large coil formed in a planar and spiral shape, and one end connected to the balanced terminal. And the other end is grounded, the first layer having a spiral first small coil formed in the same plane as the first large coil and on the inner peripheral side of the first large coil, and one end grounded The other end is connected to the balanced terminal, and the second large coil is formed in a planar and spiral shape, and one end is grounded and the other end is connected to the balanced terminal in the same plane as the second large coil. And a second layer having a spiral second small coil formed on the inner peripheral side of the second large coil, and one end connected to the unbalanced terminal and the other end grounded to form a flat and spiral shape. The third large coil formed and one end connected to the unbalanced terminal And a third layer having the other end grounded and having a third small coil formed in the same plane as the third large coil and on the inner peripheral side of the third large coil. It is characterized by becoming.

  The large coil and the small coil in each layer have different resonance frequencies, and the large coil resonates at a lower frequency than the small coil. Even if the frequency of the received signal is a wide band, balanced-unbalanced conversion can be performed as long as the frequency band includes the resonance frequencies of the large coil and the small coil.

  According to the present invention, it is possible to configure a resonator that can handle a wide-band signal with one resonator, and to achieve downsizing of a low-noise amplifier circuit that can handle a wide-band signal using the resonator. As a result, it is possible to reduce the size and cost of semiconductor devices, modules, and the like, which conventionally have a large number of components, increase costs, and are difficult to reduce in size.

  Hereinafter, examples of embodiments of the present invention will be described with reference to the accompanying drawings.

  The embodiment described below is a specific example of a preferred embodiment for carrying out the present invention, and therefore various technically preferable limitations are given. However, the present invention is not limited to these embodiments unless otherwise specified in the following description of the embodiments. Therefore, for example, the materials used in the following description, the amount used, the processing time, the processing order, the numerical conditions of each parameter, etc. are only suitable examples, and the dimensions, shapes, arrangement relationships, etc. in each drawing used for the description Is a schematic diagram showing an example.

[First Embodiment]
Below, the 1st Embodiment of this invention is described with reference to FIGS. The first embodiment will be described on the assumption that the balun resonator of the present invention is applied to a receiving device (tuner circuit) such as a television receiver.

  FIG. 1 is a block diagram showing a configuration example of a highly integrated tuner circuit such as a television receiver.

  The tuner circuit shown in FIG. 1 includes an antenna 1 that receives a broadcast wave, an RFIC 2 that selects a desired broadcast wave, a demodulation IC that extracts an original signal from the selected broadcast wave, and the like.

  The RFIC 2 includes an LNA circuit (low noise amplifier circuit) 3, a band pass filter (hereinafter simply referred to as “filter”) 4, a mixer 5, a transmitter 6 such as a VCO (voltage controlled oscillator), and an amplifier circuit 7. In the RFIC 2, the unbalanced reception signal received by the antenna 1 is converted into a balanced reception signal by the LNA circuit 3, amplified, and output to the filter 4. The filter 4 selectively passes a reception signal in a predetermined band and outputs it to the mixer 5. The mixer 5 mixes the input reception signal and the local transmission signal from the transmitter 6, converts the mixed signal into a predetermined intermediate frequency signal (IF signal), and outputs the signal to the amplifier circuit 7. The amplifier circuit 7 amplifies the IF signal and outputs it to the demodulation IC. The demodulating IC demodulates the received signal input from the RFIC 2 to generate a baseband signal, and obtains video data, audio data, and the like from the baseband signal.

  In the LNA circuit 3, a balun resonator is used to convert an unbalanced reception signal received by the antenna 1 into a balanced state. A balun resonator used in the LNA circuit 3 will be described.

  FIG. 2 is a block diagram illustrating an example of the internal configuration of the LNA circuit 3.

  As illustrated in FIG. 2, the LNA circuit 3 includes a balun resonator 12, a filter 14, and an amplifier circuit 15. In the balun resonator 12, one end on the input side is connected to the unbalanced terminal 11 and the other end is grounded, and one end on the output side is connected to the balanced terminal 13a and the other end is connected to the balanced terminal 13b. The antenna 1 is connected to the unbalanced terminal 11 of the balun resonator 12, and the input side of the filter 14 is connected to the balanced terminals 13 a and 13 b of the balun resonator 12. The filter 14 passes a predetermined band of the balanced signal input from the balun resonator 12. The amplifier circuit 15 amplifies the balanced signal in a predetermined band and outputs it to the filter 4.

  When a broadcast wave is received, a reception signal is input from the antenna 1 to the unbalanced terminal 11 of the balun resonator 12, and a reception signal is output from the balanced terminals 13a and 13b. The balun resonator 12 of this embodiment is used for reception processing. On the other hand, when transmission processing is performed by applying the balun resonator 12 to a mobile phone or the like, a transmission signal is transmitted to the balun resonator 12. The signals are input to the balanced terminals 13 a and 13 b and output from the unbalanced terminal 11 to the antenna 1. Thus, the balun resonator 12 is a device in which input-output is reversible. Therefore, which of the balanced terminal and the unbalanced terminal is set as the input side or the output side can be arbitrarily determined according to the direction in which the signal is transmitted.

  Thus, the balun resonator 12 is an element that converts an unbalanced signal and a balanced signal. Here, the balanced signal and the unbalanced signal will be described.

  A balanced signal is a signal in which, of two signal transmission lines, an original signal is flowing through one line, and a signal having an inverted phase is flowing through the other line. When the transmission line is affected by noise, the balanced signal has the opposite phase on the receiving side again (that is, the same phase as the original signal), and is added to the original signal. Since the noise component is canceled, it is suitable for transmission with high noise resistance.

  The unbalanced signal is a signal transmitted / received using one signal transmission line such as the antenna 1 as shown in FIG. 2, and ground is the reference potential of the signal. Hereinafter, the conversion between the balanced signal and the unbalanced signal is referred to as “balanced-unbalanced conversion”.

  In order to perform such balanced-unbalanced conversion, it is common to use electromagnetic induction such as a transformer. Also in the balun resonator 12 of the present embodiment described in detail below, balanced-unbalanced conversion is performed using electromagnetic induction, and this is achieved by configuring a resonator using a coil (winding). Realize. Next, the laminated structure of the balun resonator 12 will be described.

  FIG. 3 is a schematic cross-sectional view showing the concept of the laminated state of the coils constituting the balun resonator 12 shown in FIG.

  The balun resonator 12 in the present embodiment is composed of four coils, and these coils are alternately stacked in a so-called interdigital shape. Hereinafter, the four layers are referred to as a first layer, a second layer, a third layer, and a fourth layer in order from the bottom.

  In the balun resonator 12 shown in FIG. 3, one end of the first layer coil L1 is connected to the balanced terminal 13a and the other end is grounded. One end of the second layer coil L2 is grounded and the other end is connected to the balanced terminal 13b. One end of the third layer coil L3 is connected to the unbalanced terminal 11 and the other end is grounded. The fourth layer coil L4 is a coil for enhancing electromagnetic coupling between the laminated coils, and is hereinafter referred to as a “coupled coil”.

  By arranging the coils in the interdigital shape in this way, it is possible to configure a balun resonator that performs balanced-unbalanced conversion by electromagnetically coupling the coils.

  By the way, it is known that the multi-stage coil increases the coupling coefficient between the coils and widens the band. However, since the number of stages that can be multi-staged is actually limited, a low frequency (for example, It is difficult to cope with the (VHF band). Therefore, in order to further increase the bandwidth, the coils L1 to L4 of each layer shown in FIG. 3 are composed of two coils having different lengths, and each is laminated in an interdigital shape.

  FIG. 4 is a schematic cross-sectional view showing the concept of the laminated state of the coils of the balun resonator 12 in which the coils L1 to L4 of each layer are composed of two coils having different lengths.

  In the balun resonator 12 shown in FIG. 4, an interdigital balun resonator composed of a long coil and an interdigital balun resonator composed of a short coil are connected in parallel. Yes.

  For example, regarding the first layer in FIG. 4, the coil L1 of the first layer is composed of two coils L12 and L11. Hereinafter, the large coil L12 is referred to as a “large coil” and the small coil L11 is referred to as a “small coil”, and the other layers of the coil are applied mutatis mutandis. One end of the large coil L21 and the small coil L11 of the first layer is connected to the balanced terminal 13a, and the other end is grounded.

  The second layer coil L2 includes a large coil L22 and a small coil L21. One ends of the large coil L21 and the small coil L11 are grounded, and the other end is connected to the balanced terminal 13b.

  The third layer coil L3 includes a large coil L32 and a small coil L31. One end of the large coil L32 and the small coil L31 is connected to the unbalanced terminal 11, and the other end is grounded.

  The fourth layer coil L4 includes a large coil L42 and a small coil L41. One end is grounded and the other end is open. When the large coils of each layer are collectively referred to as “lc”, the small coils are collectively referred to as “sc”.

  The large coil and the small coil in each layer have different resonance frequencies, and the large coil resonates at a lower frequency than the small coil. Therefore, resonance can be generated between the balanced terminal and the unbalanced terminal by resonating with a large frequency at a low frequency that does not resonate with a small coil. For this reason, even if the frequency of the received signal is a wide band, the balance-unbalance conversion can be performed by the balun resonator 12 if the frequency band includes the resonance frequencies of the large coil and the small coil.

  In the example of FIG. 4, the large coil lc is shown to be positioned on the small coil sc, but this can clearly distinguish the electrical connection state of the large coil lc and the small coil sc. This is because it is conceptually drawn and is different from the actual arrangement. These actual arrangements will be described with reference to FIGS. 5 and 6A to 6D.

  Also, the fourth layer large coil L42 and small coil L41 located at the top of the balun resonator shown in FIG. 4 are not connected to any of the balanced terminals 13a, 13b and the unbalanced terminal 11, but this This is for the purpose of acting as a coupling coil for increasing the coupling coefficient of the coil of each layer. The order in which the coils of each layer are stacked is not limited to the illustrated example. For example, the coupling coil positioned in the uppermost fourth layer may be disposed in the lowermost part.

  FIG. 5 is a perspective view showing a specific arrangement of coils in each layer of the balun resonator 12.

  The coils of each layer have a structure in which a winding is wound spirally (spirally) in a certain plane, and the winding center is located on the inner peripheral side of the large coil lc in the same plane as the large coil lc. The same small coil sc is arranged.

  Further, the connection wiring 71 for connecting the coils of each layer to the balanced terminals 13a, 13b or the unbalanced terminal 11 and the ground wiring 72 for connecting to the ground (ground) are formed in the uppermost layer, that is, the fourth layer.

  In the example shown in FIG. 4, the coupling coils (L42, L41) are formed in the uppermost fourth layer. However, since the wiring for grounding or connecting to the balanced terminals 13a, 13b or the unbalanced terminal 11 is formed in the fourth layer of the uppermost layer, the coupling coil should be located in the lowermost layer. The structure of the balun resonator 12 is preferable without being complicated. Therefore, in the balun resonator shown in FIG. 4, the coupling coils (L42, L41) are arranged in the uppermost layer, but in the balun resonator shown in FIG. 5, the coupling coils (L42, L41) are arranged in the lowermost layer. Arranged in one layer, the other layers are completely opposite to the case of FIG. 4 in order of the second layer (L32, L31), the third layer (L22, L21), and the fourth layer (L12, L11) from the bottom. It shall be laminated.

  6 is a top view of a coil of each layer of the balun resonator shown in FIG. 5, where (a) is the first layer, (b) is the second layer, (c) is the third layer, and (d) is the third layer. The fourth layer is shown.

  Hereinafter, description will be made in order from the first layer of the lowest layer. As shown in FIG. 6, the ground terminal or the location connected to the installation terminal is indicated by “_ (G)” together with a reference so that it can be understood. Similarly, terminals connected to the balanced terminal 11 and the unbalanced terminals 13a and 13b are denoted as “_ (11)”, “_ (13a)”, and “_ (13b)”.

  The first lowermost layer is a layer in which a coupling coil is formed, a large coil L42 in which windings are formed in a planar shape and a spiral shape, and in the same plane as the large coil L42 and on the inner peripheral side thereof. It has the formed small coil L41. One end 22 of the large coil L42 is connected to a ground terminal or connected to an external ground terminal, and is wound from the end 22 toward the inner peripheral side while reducing the winding radius, and the other end. Part 24 is open. One end 21 of the small coil 41 is connected to the ground terminal (G) of the small coil L41 for grounding, and the inner peripheral end 23 of the small coil L41 is open. Hereinafter, since the structures of the large coil and the small coil of the second layer, the third layer, and the fourth layer are the same as those of the first layer, detailed description of the structures of those coils is omitted. .

  The large coil 42 and the small coil 41 of the first layer of the present embodiment are formed in a rectangular spiral shape as shown in FIG. 6A, but may be formed in an annular shape. In this case, it is preferable in terms of quality that both of them coincide with the coil winding center. Similarly, for the second to fourth layers, the large coil and the small coil may be formed in a rectangular spiral shape or an annular shape.

  The second layer is a layer in which a coil for unbalanced connection is formed. The large coil L32 and the small coil 31 are formed on the inner peripheral side of the large coil 32. One end on the outer peripheral side of the large coil 32 of the second layer is connected to an unbalanced terminal 35 (11) connected to the unbalanced terminal, and the other end on the inner peripheral side is a ground terminal 34 (G) for grounding. Connected to. One end on the outer peripheral side of the small coil L31 of the second layer is connected to the unbalanced terminal 33 (11) connected to the unbalanced terminal, and the other end on the inner peripheral side is connected to the ground terminal 32 (for grounding). G).

  Further, a via 70 connected to the ground terminal 21 (G) is formed on the outer peripheral side of the second layer small coil L31 at a position corresponding to the ground terminal 21 (G) of the first layer small coil L41. A via hole 31 is formed.

  The third layer is a layer on which a coil for balanced connection is formed, and a small coil L21 is formed on the inner peripheral side of the large coil 22 of the third layer. One end on the outer peripheral side of the third layer large coil L22 is formed with a terminal 44 (G) extending to the outside of the third layer for grounding, and the other end located on the inner peripheral side is connected to a balanced terminal. Connected to a balanced terminal 43 (13b). Further, one end on the outer peripheral side of the third coil L21 of the third layer is connected to the ground terminal 42 (G) for grounding, and the other end on the inner peripheral side is connected to the balanced terminal 41 (13a) connected to the balanced terminal. Connecting.

  A via hole 47 for forming a via of the unbalanced terminal 35 (11) of the second layer large coil L32 is formed on the outer peripheral side of the third layer large coil L22 and adjacent to the end 44 (G). Has been. In addition, a via hole 45 is formed at a position corresponding to the unbalanced terminal 33 (11) of the second layer small coil L31 on the outer peripheral side of the third layer small coil L21 and adjacent to the ground terminal 42 (G). ing.

  A via hole 46 for forming a via for the ground terminal 34 (G) of the second layer large coil L32 is formed on the inner peripheral side of the third layer large coil L22 and on the balanced terminal 43 (13b) side. Has been. A via hole 48 for forming a via for the ground terminal 32 (G) of the second layer small coil L31 is formed on the inner peripheral side of the third layer small coil L21.

  The uppermost fourth layer is a layer in which a balanced input coil is formed. A small coil L12 is formed on the inner peripheral side of the fourth layer large coil L11. One end on the outer peripheral side of the large coil L12 of the fourth layer is connected to the balanced terminal 60 (13b) connected to the balanced terminal, and the other end on the inner peripheral side is connected to the ground terminal 43 (G) for grounding. ing. One end on the outer peripheral side of the fourth coil L11 of the fourth layer is connected to a balanced terminal 53 (13b) connected to the balanced terminal, and the other end on the inner peripheral side is connected to the ground terminal 52 (G).

  On the balanced terminal 60 (13b) side of the fourth layer large coil L12, a connection terminal 55 for connecting the second layer large coil L32 and the second layer small coil L31 is formed. On the balanced terminal 53 (13b) side of the fourth layer small coil L11, a connection terminal 54 for connecting the second layer large coil L32 and the second layer small coil L31 is formed. Further, the second layer connection terminal 55 and the second layer connection terminal 54 are connected to each other by a second layer connection wiring 71. The connection wiring 71 is formed so as not to contact the fourth layer large coil L12 through an insulating film or the like, for example.

  Further, a fourth layer connection wiring 71 is formed to connect the fourth layer balanced terminal 60 (13b) and the fourth layer balanced terminal 53 (13b) to each other. For grounding the third layer ground terminal 42 (G) and the first layer ground terminal 21 (G) to the fourth layer balanced terminal 53 (13b) side on the outer peripheral side of the fourth layer small coil L11. A relay terminal 58 is formed. The relay terminal 58 is grounded by the ground wiring 72 on the outer peripheral side of the fourth layer large coil L12. The ground wiring 72 extends from the relay terminal 58 to the ground (not shown) on the outer circumference side of the fourth layer large coil L12 in a direction crossing the fourth layer large coil L12 via an insulating film, for example. It is formed.

  A relay unbalanced terminal 59 connected to the balanced terminal 41 (13a) of the third layer small coil L21 is formed adjacent to the ground terminal 52 (G) of the fourth layer small coil L11. Further, a relay balanced terminal 56 connected to the balanced terminal 43 (13b) of the third layer large coil L22 is formed on the inner peripheral side of the fourth layer large coil L12.

  A balanced connection terminal 57 connected to the balanced terminal 13a (not shown) is formed on the outer peripheral side of the fourth layer large coil L12, and is connected to the relay balanced terminal 56 by the connection wiring 71. The connection wiring 71 is formed so as to cross the fourth layer small coil L11 via an insulating film or the like, for example.

  The balun resonator 12 thus formed in a laminated structure can be configured by being embedded in, for example, resin (not shown in FIG. 4).

  Next, a cross-sectional structure of the balun resonator 12 will be described with reference to FIG.

  FIG. 7 is a schematic cross-sectional view of the balun resonator 12 shown in FIGS. 5 and 6. The thickness of each of the first to fourth layers is about 20 μm, for example, and the distance between the layers is about 20 μm, for example. Further, the lower part of the first layer and the upper part of the fourth layer are in the same state as the air release. That is, the permittivity and permeability are equivalent to the atmosphere. In addition, a thin film can be formed between each layer using an insulating material. As the insulating material, polyimide, BCB (Benzocyclobutene), or the like can be used.

  Next, an LNA circuit having a balun resonator according to the present embodiment will be described.

  FIG. 8 shows an LNA circuit configured using the balun resonator 12 of this embodiment and corresponding to three frequency bands. The three frequency bands are 550 to 900 MHz, 180 to 550 MHz, and 46 to 180 MHz, and are hereinafter referred to as “first circuit”, “second circuit”, and “third circuit”, respectively. However, these are used to identify each circuit, and which circuit is referred to as “first”, “second”, and “third” may be arbitrary. The first circuit, the second circuit, and the third circuit each include elements of the filter 14 and the differential amplifier 15, and are connected in parallel.

  The first circuit, the second circuit, and the third circuit are all connected in parallel to the same circuit and the balun resonator 12. Here, the first circuit will be described as a representative, and description of the other second circuit and third circuit will be omitted.

  As shown in FIG. 8, a switching transistor 80A in which the gates of two field effect transistors 80A1 and 80A2 are connected to each other is connected to the balanced terminals 13a and 13b of the balun resonator 12. In addition, a variable capacitance element 81A and a resistance element 82A are connected in parallel to the switching transistor 80A. Both ends of the resistance element 82A are connected to the input ends of the differential amplifier 84A.

  The variable capacitance element 81A constitutes a device (capacitor bank 81) that can form an arbitrary capacitance by, for example, connecting a plurality of variable capacitance elements in parallel and freely changing the capacitance of each variable capacitance element. To do. Therefore, for example, in the frequency band of the third circuit, that is, 46 to 180 MHz, the variable capacitance element 81A and the balun resonator 12 constitute an LC resonance circuit and function as a filter.

  Further, in order to increase the bandwidth, an inductor is connected to the outside of the LNA circuit in the high frequency band excluding the 46-180 MHz band. As shown in FIG. 9, in addition to the LNA circuit on the low frequency side, inductors 83A and 83B are connected in parallel between the balun resonator 12 and the switching transistor 80A or 80B.

  The LNA circuit shown in FIG. 9 includes, in addition to the LNA circuit shown in FIG. 8, an output side variable capacitance element 85A using a capacitor bank on the output side of each of the differential amplifiers 84A to 84C in the first to third circuits. To 85C and output side inductors 86A to 86C are connected in parallel to constitute a filter 4a. That is, the filters 14 and 4a are provided on the input side and output side of the differential amplifiers 84A to 84C, respectively. This is because an unnecessary signal component cannot be sufficiently removed by the filter on the input side, and therefore an unnecessary signal is removed by providing a filter on the output side.

  Further, for the third circuit, in addition to the configuration of the first circuit or the second circuit, a filter 4b including variable capacitance elements 87c1, 87c2, 87c3 and an inductor 88c is connected to the output side of the filter 4a. Yes. By providing a large number of filters in this manner, it is possible to extract an electrical signal having a very narrow bandwidth with respect to the frequency band (46 to 180 MHz) of the LNA circuit, for example, with a bandwidth of 8 MHz.

  Next, signal characteristics when a capacitor bank is connected to the balun resonator 12 and the capacitance of the capacitor bank is changed in the range of about 0 pF to 300 pF will be described. When measuring the signal characteristics, the width of the line forming the coil of each layer of the balun resonator 12, the distance between the lines, that is, the line width / space (line / space) is 20 μm / 20 μm, the thickness between the layers is 15 μm, The non-dielectric constant was assumed to be 3.0 and the dielectric loss tangent was assumed to be 0.03. The diameter of the bonding wire was assumed to be 30 μm.

  FIG. 10 shows signal characteristics representing the relationship between frequency and insertion loss. The horizontal axis of the graph is the frequency of the input signal, and the vertical axis is the insertion loss. Looking at the graph of the region where the capacitance of the capacitor bank is close to 0 pF, the insertion loss is small at about 0.4 GHz or less, but the insertion loss is the largest at the region above it.

  In addition, when the capacitance is 0.5 pF, the peak has a maximum insertion loss in the vicinity of about 0.34 GHz, and the minimum value is in the vicinity of 0.77 GHz. As shown in the figure, as the capacity increases, the peak frequency decreases and the insertion loss near the minimum value decreases. Further, the frequency has a maximum value in the range of 0.9 GHz to 1 GHz, and decreases from around 0.95 GHz.

  As described above, in the frequency range of 0.0 GHz to 1.0 GHz, as the capacitance of the capacitor bank connected to the balun resonator 12 increases, the insertion loss decreases at a frequency of about 0.4 GHz or more. At about 0.4 GHz or less, the frequency at which the insertion loss is maximized is lowered and the insertion loss is also reduced.

  That is, by adjusting the capacitance of the variable capacitance element 81 by the capacitor bank, the balun resonator 3 functions as a differential inductor that resonates with respect to signals having opposite phases at a low frequency. Therefore, it becomes a simple LC resonance circuit and operates as an LC filter. On the other hand, by adding capacity at a high frequency, the peak frequency can be shifted to the low frequency side. By such an operation, a low noise amplifier circuit corresponding to a wide band can be realized.

  As described above, the balun resonator 12 of the present embodiment can correspond to a plurality of frequency bands by one balun resonator 12 by changing the capacitance of the capacitor bank. As a result, the mother board can be reduced in size.

FIG. 11 is a top view showing a state in which the balun resonator according to the present embodiment is installed on the mother board.
As shown in the figure, the RFIC 2 is installed on the mother substrate 100, and the balun resonator 12 is installed on the left side of the RFIC 2. An inductor 83 is installed adjacent to the RFIC 2 and the balun resonator 12. The inductor may be an element having inductance, and for example, a coil can be used. Compared with the conventional example shown in FIG. 18, it can be seen that the mother substrate 100 is downsized in the example shown in FIG. 11 because there is one balun resonator 12.

  Next, the structure of a semiconductor device (module) in which the balun resonator 12 according to the present embodiment is mounted on the mother substrate 100 will be described.

  FIG. 12 is a schematic cross-sectional view of a semiconductor device in which the balun resonator 3 and the RFIC 2 are installed on the main surface of the mother substrate 100.

  As the mother board 100, a so-called printed wiring board, which is normally used as an example, can be used. The connection between the printed wiring (not shown) of the mother substrate 100 and the terminals of the balun resonator 3 can be made by a normal bonding wire 101 as shown in FIG. This bonding wire 101 is different from the connection wiring 71 and the ground wiring 72 shown in FIGS.

  Note that the form of the semiconductor device in which the balun resonator 12 and the RFIC 2 are mounted on the mother substrate 100 is not limited to the example shown in FIG. Hereinafter, modifications of the semiconductor device including the balun resonator 12 and the RFIC 2 will be described.

(First modification)
A first modification of the semiconductor device including the balun resonator 12 shown in FIG. 12 will be described with reference to FIG.

  FIG. 13 is a schematic cross-sectional view showing a state where the balun resonator 12 and the RFIC 2 are embedded in the mother substrate 100.

  In this example, since the balun resonator 12 and the RFIC 2 are embedded in the mother substrate 100, the connection between the balun resonator 12 and the printed wiring of the mother substrate 100 is performed by the bonding wire 101 as in FIG. In this example, since the balun resonator 12 and the RFIC 2 are embedded in the mother substrate 100, the entire thickness including the mother substrate 100 can be reduced. Note that the RFIC 2 is not necessarily embedded.

(Second modification)
FIG. 14 is a schematic cross-sectional view showing a second modification of the semiconductor device including the balun resonator 12 shown in FIG.

  In the second modification, the connection member 110 is used for connection between the balun resonator 12 and the printed wiring (not shown) of the mother board 100. The connecting member 110 is formed by forming a conductive member 103 having conductivity in a plate-like member having insulating properties (hereinafter referred to as “insulating member” 102). The conductive member 103 is configured to penetrate the insulating member 102 as shown in FIG. 14, and between the upper and lower surfaces of the connecting member 110, that is, between the balun resonator 12 and the mother substrate 100. Can be electrically connected. As the conductive member 103, a so-called copper post (Cu Post), bump post (Bump Post), or the like can be used.

  The conductive member 103 is formed at a position corresponding to each terminal of the coil of the balun resonator 12 shown in FIG. For example, in FIG. 5, the conductive member 103 is formed at a position corresponding to the ground terminal 58 connected to the ground terminal 42 of the third layer small coil L21 and the ground wiring 72 of the fourth layer. In addition, the conductive member 103 is formed at a corresponding position between the layers.

  In FIG. 14, the connection member 110 is shown to be approximately the same as the thickness of the balun resonator 12, because this is schematically shown to explain a second modification of the semiconductor device. . The connecting member 110 can also be formed in a thin film shape, which may be arbitrarily formed as necessary. The distance between the lowermost coil of the balun resonator 12 and the printed wiring of the mother board 100 is preferably, for example, 80 μm to 150 μm as a distance that does not act electrically. In this way, when the connection member 110 is used for electrical connection between the balun resonator 12 and the mother substrate 100, the bonding wire 110 can be omitted, so that the wire bonding process can be omitted from the manufacturing process.

(Third Modification)
Next, a third modification of the semiconductor device including the balun resonator 12 will be described.

  FIG. 15 is a schematic cross-sectional view showing a third modification of the semiconductor device shown in FIG. In the semiconductor device shown in FIG. 15, a connecting member 110 is used between the balun resonator 12 and the mother substrate 100, and a coupling plate F is further installed. This coupling plate is a plate-like member made of a material having a higher magnetic permeability than the atmosphere. As shown in the figure, the coupling plate F is installed on the balun resonator 12. Further, when the coupling plate F is disposed below the balun resonator 12, the coupling plate F is disposed so as to be embedded in the mother substrate 100.

  By installing the coupling plate F, the coupling coefficient of the coil between each layer (first layer to second layer) of the balun resonator 12 can be increased, and the balance-unbalance conversion efficiency can be increased. For example, if the coupling plate F is formed of a material having a magnetic permeability of 400, the coupling coefficient is about four times that in the case where the coupling plate F is not used. However, this can change the coupling coefficient freely by changing the material of the coupling plate F or the magnetic permeability.

(Fourth modification)
Next, another form of the third modification will be described as a fourth modification of the first embodiment.

  FIGS. 16A and 16B show the structure of a balun resonator according to a fourth modification, wherein FIG. 16A is a top view and FIG. 16B is a cross-sectional view taken along line A-A ′. According to the fourth modification, the connection wiring 71 and the ground wiring 72 for the large coil lc and the small coil sc can be formed in the uppermost layer (fourth layer). Note that in this fourth modification, description of the same components as those in the first embodiment described above will be omitted.

  As shown in FIG. 16 (a), the plate-like members 111 and 112 made of a material having a high magnetic permeability compared to the magnetic permeability of the atmosphere are partially made up of the large coil lc and the small coil sc. Install to cover. For example, ferrite can be used as a material having high magnetic permeability. Hereinafter, for convenience of explanation, a plate-like member formed of a material having high magnetic permeability is referred to as a “coupling plate”. The coupling plates 111 and 112 are assumed to have a thickness of 50 μm to 100 μm. As long as the coupling coefficient of the coil of each layer can be made high, the thickness of the coupling plates 111 and 112 may be arbitrary.

  The coupling plates 111 and 112 have a function as a reinforcing plate that increases the physical strength of the balun resonator 12. The strength increases as the thickness of the coupling plates 111 and 112 increases. However, the thickness of the coupling plates 111 and 112 only needs to have a required strength.

  As shown in FIG. 16 (a), the two coupling plates 111 and 112 are spaced apart so as to have a gap 113. This is because the connection wiring 71 and the ground wiring 72 are formed from the gap 113 toward the outer peripheral side of the large coil lc. Further, as shown in FIG. 16B, the coupling plates 111 and 112 are disposed on the upper and lower portions of the large coil lc and the small coil sc, and thereby, each layer (first layer to fourth layer) is arranged. The coupling coefficient of the coil can be increased. The respective coupling plates will be referred to as “upper coupling plate 111” and “lower coupling plate 112”.

  In FIGS. 16A and 16B, the edges of the coupling plates 111 and 112 are configured such that the gap 113 coincides with the edge 114 on the inner peripheral side of the small coil sc. However, the present invention is not limited to this. It is not something. Since the fourth modification is characterized in that the coupling plates 111 and 112 are installed in order to increase the coupling coefficient of the coils of each layer, the arrangement of the coupling plates can be arbitrarily set.

  From this gap 113, the connection wiring 71 and the ground wiring 72 (not shown in FIGS. 16A and 16B) can be extended to the outside. The coupling plates 111 and 112 can be fixed with the large coil lc and the small coil sc together with the resin 115 together with the large coil lc and the small coil sc.

  However, the arrangement of the coupling plates 111 and 112 is not limited to this. For example, the large coil lc and the small coil sc are covered with the resin 115A, and the coupling plates 111 and 112 are bonded to the surface of the resin 115A with an adhesive or the like. Even with a structure to do.

(Fifth modification)
Next, another example of the arrangement of the coupling plates will be described with reference to FIG. FIG. 17A is a top view of a balun resonator according to a fifth modification, and FIG. 17B is a cross-sectional view taken along the line BB ′. As shown in FIGS. 17A and 17B, the coupling plates 121 and 122 have an annular shape having a through-hole 123 at the center and cover the large coil lc. Not covered. Further, since the thicknesses of the coupling plates 121 and 122 are the same as those of the above-described fourth modified example, the description thereof is omitted.

  From this through hole 123, the connection wiring 71 and the ground wiring 72 can be extended to the outside. As shown in FIG. 13B, the coupling plate is composed of an upper coupling plate 121 and a lower coupling plate 122. Even in such a configuration, the coupling coefficient of the large coil lc in each layer can be increased.

  In the fifth modification, the connection wiring 71 and the ground wiring 72 (not shown in FIGS. 12A and 12B) can be extended to the outside from the through hole 123. Further, the large plates lc and small coils sc and the coupling plates 121 and 122 can be fixed by covering the coupling plates 121 and 122 with the resin 124 together with the large coils lc and small coils sc.

  In the example of the present embodiment, the frequency band is divided into three by three low noise amplifier circuits, but the present invention is not limited to this. For example, two or four frequency bands are used. It can be divided into any number such as five.

  Further, in the above-described embodiment, the coil is formed in a spiral shape within a certain plane, but may be a meander shape. The meander shape is defined as a rectangular fold, a zigzag fold, a waveform, and the like that are arranged with a certain density or more in a certain area while bending a linear body. Practically, rectangular folds and spelled folds are preferred.

  In the above-described embodiment, the example in which the balun resonator is used in a tuner circuit or a television receiver including the tuner circuit has been described. However, the balun resonator can also be used in a wireless receiver or the like. Further, various modifications and changes can be made without departing from the gist of the present invention, such as being used not only for reception but also for transmission / reception functions of a wireless transmitter and a mobile phone.

1 is a block diagram showing an internal configuration of a tuner circuit according to a first embodiment of the present invention. 2 is a block diagram showing an internal configuration of an LNA circuit used in the tuner circuit according to the first embodiment of the present invention. FIG. It is the cross-sectional schematic diagram which showed the concept of the lamination | stacking state of the coil which comprises a general balun resonator. It is the cross-sectional schematic diagram which showed the concept of the lamination | stacking state of the coil which comprises the balun resonator which concerns on the 1st Embodiment of this invention. It is the perspective view which showed the structure of the balun resonator which concerns on the 1st Embodiment of this invention. It is a top view of the coil of each layer of the balun resonator which concerns on the 1st Embodiment of this invention, (a) is the 1st layer, (b) is the 2nd layer, (c) is the 3rd layer, (d ) Shows the fourth layer. It is a schematic sectional drawing which shows the layer structure of the balun resonator which concerns on the 1st Embodiment of this invention. It is a figure which shows the LNA circuit which uses the balun resonator which concerns on the 1st Embodiment of this invention. It is a figure which shows the LNA circuit (2) using the balun resonator which concerns on the 1st Embodiment of this invention. It is a graph which shows the relationship between the frequency and insertion loss in the balun resonator which concerns on the 1st Embodiment of this invention. It is a top view of the board | substrate with which the balun resonator which concerns on the 1st Embodiment of this invention is arrange | positioned. It is sectional drawing of the board | substrate which mounted the balun resonator which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the 1st modification of the 2nd Example of this invention. It is sectional drawing which shows the 2nd modification of the 2nd Example of this invention. It is sectional drawing which shows the 3rd modification of the 2nd Example of this invention. The structure of the balun resonator based on the 3rd Embodiment of this invention is shown, (a) is a top view, (b) is sectional drawing cut | disconnected by the A-A 'line | wire. FIG. 9 shows a modification of the balun resonator according to the third embodiment of the present invention, where (a) is a top view and (b) is a cross-sectional view taken along line B-B ′. It is a figure which shows the LNA circuit using the conventional balun resonator. It is sectional drawing of the board | substrate which mounted the conventional balun resonator.

Explanation of symbols

  3 ... LNA circuit, 4 ... filter, 11 ... unbalanced terminal, 12 ... balun resonator, 13a, 13b ... balanced terminal, 14 ... filter, 15 ... amplifier circuit, 81 ... capacitor bank, 80A, 80B, 80C ... switching transistor L11 ... fourth layer small coil, L12 ... fourth layer large coil, L21 ... third layer small coil, L22 ... third layer large coil, L31 ... second layer small coil, L32 ... second layer large coil, L41 ... 1st layer small coil, L42 ... 1st layer large coil

Claims (6)

A first large coil having one end connected to the balanced terminal and the other end grounded, and formed in a planar and spiral shape;
A spiral first small coil having one end connected to the balanced terminal and the other end grounded, formed in the same plane as the first large coil and on the inner peripheral side of the first large coil;
A first layer having:
A second large coil having one end grounded and the other end connected to a balanced terminal and formed in a planar and spiral shape;
A spiral second small coil having one end grounded and the other end connected to a balanced terminal, formed in the same plane as the second large coil and on the inner peripheral side of the second large coil;
A second layer having:
A third large coil having one end connected to the unbalanced terminal and the other end grounded, formed in a planar and spiral shape;
A spiral third small coil having one end connected to the unbalanced terminal and the other end grounded, formed in the same plane as the third large coil and on the inner peripheral side of the third large coil;
A third layer having:
Is a laminated balun resonator. The balun resonator according to claim 1, wherein the spiral shape is a square spiral shape. A fourth large coil having one end grounded and the other end open and formed in a planar and spiral shape;
One end is grounded and the other end is opened, and a spiral fourth small coil formed in the same plane as the fourth large coil and on the inner peripheral side of the fourth large coil;
A fourth layer having:
The balun resonator according to claim 2, wherein the fourth layer is stacked on the first layer, the second layer, and the third layer. The balun resonator according to claim 3, wherein a plate material having high magnetic permeability is further laminated on the first layer, the second layer, and the third layer. A first large coil having one end connected to the balanced terminal and the other end grounded, and formed in a planar and spiral shape;
A spiral first small coil having one end connected to the balanced terminal and the other end grounded, formed in the same plane as the first large coil and on the inner peripheral side of the first large coil;
A first layer having:
A second large coil having one end grounded and the other end connected to a balanced terminal and formed in a planar and spiral shape;
A spiral second small coil having one end grounded and the other end connected to a balanced terminal, formed in the same plane as the second large coil and on the inner peripheral side of the second large coil;
A second layer having:
A third large coil having one end connected to the unbalanced terminal and the other end grounded, formed in a planar and spiral shape;
A spiral third small coil having one end connected to the unbalanced terminal and the other end grounded, formed in the same plane as the third large coil and on the inner peripheral side of the third large coil;
A third layer having:
A balun resonator formed by stacking,
A variable capacitance element is connected between balanced terminals of the balun resonator, and an input terminal of a differential amplifier is connected to both ends of the variable capacitance element. A first large coil having one end connected to the balanced terminal and the other end grounded, and formed in a planar and spiral shape;
A spiral first small coil having one end connected to the balanced terminal and the other end grounded, formed in the same plane as the first large coil and on the inner peripheral side of the first large coil;
A first layer having:
A second large coil having one end grounded and the other end connected to a balanced terminal and formed in a planar and spiral shape;
A spiral second small coil having one end grounded and the other end connected to a balanced terminal, formed in the same plane as the second large coil and on the inner peripheral side of the second large coil;
A second layer having:
A third large coil having one end connected to the unbalanced terminal and the other end grounded, formed in a planar and spiral shape;
A spiral third small coil having one end connected to the unbalanced terminal and the other end grounded, formed in the same plane as the third large coil and on the inner peripheral side of the third large coil;
A third layer having:
A balun resonator formed by stacking,
And a semiconductor device in which a variable capacitance element is connected between balanced terminals of the balun resonator, and an input terminal of a differential amplifier is connected to both ends of the variable capacitance element.

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