JP5532945B2 - Circuit module - Google Patents

Description

  The present invention relates to a circuit module, and more specifically to a circuit module provided with an isolator.

  As a conventional isolator, for example, a non-reciprocal circuit device described in Patent Document 1 is known. The nonreciprocal circuit element includes a pair of ferrite having a main surface facing each other, a plurality of center electrodes, a permanent magnet having a main surface facing the main surface of the ferrite, and a circuit board. The plurality of center electrodes are formed of a conductor film in a state of being insulated from and intersecting the main surface of the permanent magnet, and are electrically connected via a relay electrode formed on an end surface orthogonal to the main surface of the ferrite. ing. Furthermore, both the ferrite and the permanent magnet are arranged on the circuit board in the direction in which the respective principal surfaces are orthogonal to the surface of the circuit board. The non-reciprocal circuit device as described above is used in, for example, a communication device.

  Incidentally, in recent years, with the demand for miniaturization of communication devices, the demand for miniaturization of isolators has increased. Accordingly, it has been proposed to remove the yoke for suppressing the magnetic field from leaking outside in the non-reciprocal circuit device described in Patent Document 1.

  However, when the yoke is removed from the nonreciprocal circuit element, a magnetic field leaks around the isolator. For this reason, the magnetic field penetrates through the electronic component arranged in the vicinity of the non-reciprocal circuit element, and the characteristics of the electronic component vary from the original characteristics.

JP 2006-31455 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce an adverse effect caused by a magnetic field of an isolator on an electronic component arranged around the isolator in a circuit module on which an isolator having no yoke is mounted.

A circuit module according to a first aspect of the present invention includes a circuit board, a ferrite, a permanent magnet that applies a DC magnetic field to the ferrite, and one end electrically connected to the input port. A first center electrode having one end connected to the output port, and the ferrite provided to intersect the first center electrode in an insulated state, one end connected to the output port, and the other end to the ground port A core isolator having a second center electrode connected thereto, wherein the core isolator is mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board; A first electronic component constituting an isolator together with a core isolator, the first electronic component mounted on the circuit board, and a second electronic unit not constituting the isolator A is, and a second electronic component mounted on the circuit board, when viewed in plan from a normal direction of the circuit board, and the ferromagnetic member which is provided so as to overlap with the core isolator, and and a coating provided on said circuit board so as to cover the core isolator, said ferromagnetic member is provided on the coating, the coating may be a metal case The ferromagnetic member is provided on a surface parallel to the main surface of the circuit board in the metal case so as to face the core isolator, and is parallel to the main surface of the circuit board in the metal case. A convex portion that protrudes toward the core isolator is formed on the surface, and the ferromagnetic member is provided on the convex portion .
A circuit module according to a second aspect of the present invention includes a circuit board, a ferrite, a permanent magnet that applies a DC magnetic field to the ferrite, and one end electrically connected to the input port. A first center electrode having one end connected to the output port, and the ferrite provided to intersect the first center electrode in an insulated state, one end connected to the output port, and the other end to the ground port A core isolator having a second center electrode connected thereto, wherein the core isolator is mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board; A first electronic component constituting an isolator together with a core isolator, the first electronic component mounted on the circuit board, and a second electronic unit not constituting the isolator The second electronic component mounted on the circuit board, and a ferromagnetic member provided to overlap the core isolator when viewed in plan from the normal direction of the circuit board, A covering provided on the circuit board so as to cover the core isolator, and the ferromagnetic member is provided on the covering, which is an insulating resin, and the insulating resin. Are laminated in the normal direction of the circuit board, and the ferromagnetic member is provided between the layers of the insulating resin.
A circuit module according to a third aspect of the present invention includes a circuit board, a ferrite, a permanent magnet that applies a DC magnetic field to the ferrite, and one end electrically connected to the input port. A first center electrode having one end connected to the output port, and the ferrite provided to intersect the first center electrode in an insulated state, one end connected to the output port, and the other end to the ground port A core isolator having a second center electrode connected thereto, wherein the core isolator is mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board; A first electronic component constituting an isolator together with a core isolator, the first electronic component mounted on the circuit board, and a second electronic unit not constituting the isolator The second electronic component mounted on the circuit board, and a ferromagnetic member provided to overlap the core isolator when viewed in plan from the normal direction of the circuit board, A covering provided on the circuit board so as to cover the core isolator, and the ferromagnetic member is provided on the covering that is an insulating resin, and the ferromagnetic member Is provided in the insulating resin and has a portion facing the side surface of the core isolator.

  ADVANTAGE OF THE INVENTION According to this invention, the bad influence by the magnetic field of an isolator with respect to the electronic component arrange | positioned around the isolator can be reduced.

It is an arrangement plan of electronic parts mounted on a circuit module according to an embodiment of the present invention. It is a block diagram of the circuit module of FIG. It is a disassembled perspective view of the circuit module of FIG. It is an external appearance perspective view of an isolator. It is an external appearance perspective view of the ferrite provided with the center electrode. It is an external appearance perspective view of a ferrite. It is a disassembled perspective view of a core isolator. It is an equivalent circuit diagram of an isolator. FIG. 2 is a cross-sectional structure diagram of the circuit module of FIG. 1. It is the graph which showed the insertion loss characteristic of the isolator. It is the graph which showed the isolation characteristic of the isolator. It is a sectional structure figure of a circuit module concerning the 1st modification. It is a sectional structure figure of a circuit module concerning the 2nd modification. It is a sectional structure figure of a circuit module concerning the 3rd modification. It is a cross-section figure of the circuit module which concerns on a 4th modification. It is a cross-section figure of the circuit module which concerns on a 5th modification. It is a cross-section figure of the circuit module which concerns on a 6th modification. It is sectional structure drawing of the circuit module which concerns on a 7th modification. It is sectional structure drawing of the circuit module which concerns on an 8th modification.

  A circuit module according to an embodiment of the present invention will be described below with reference to the drawings.

(Configuration of circuit module)
First, the configuration of the circuit module will be described with reference to the drawings. FIG. 1 is a layout view of electronic components mounted on a circuit module 1 according to an embodiment of the present invention. FIG. 2 is a block diagram of the circuit module 1 of FIG. FIG. 3 is an exploded perspective view of the circuit module 1 of FIG. In FIGS. 1 and 3, only main electronic components are shown, and detailed electronic components such as a chip capacitor and a chip inductor are omitted.

  The circuit module 1 constitutes a part of a transmission circuit of a wireless communication device such as a mobile phone, and amplifies and outputs a plurality of types of high-frequency signals. The circuit module 1 includes a circuit board 2 and transmission paths R1 and R2. The circuit board 2 is a plate-like printed multilayer board having an electric circuit formed on the surface and inside.

  The transmission path R1 amplifies the input signals RFin_BC0 (800 MHz band) and RFin_BC3 (900 MHz band) and outputs them as output signals RFout_BC0 (800 MHz band) and RFout_BC3 (900 MHz band). The transmission path R1 includes SAW filters (surface wave filters) 3a and 3b, a switch 4, a power amplifier (amplifier) 6a, a coupler 7, an isolator 8a, and a switch 9. The SAW filters 3a and 3b, the switch 4, the power amplifier 6a, the coupler 7, the isolator 8a, and the switch 9 are electronic components mounted on the circuit board 2 as shown in FIGS.

  As shown in FIGS. 1 and 3, the SAW filters 3a and 3b are configured by one electronic component, and are band-pass filters that allow only a signal having a predetermined frequency to pass therethrough. The SAW filters 3a and 3b are electrically connected to an input terminal (not shown) of the power amplifier 6a via the switch 4. An input signal RFin_BC3 is input to the SAW filter 3a. Further, the input signal RFin_BC0 is input to the SAW filter 3b.

  The switch 4 is connected to the SAW filters 3a and 3b and the power amplifier 6a, and as shown in FIG. 2, the input signal RFin_BC3 output from the SAW filter 3a or the input signal RFin_BC0 output from the SAW filter 3b. Either one is output to the power amplifier 6a.

  The power amplifier 6a amplifies the input signals RFin_BC0 and RFin_BC3 output from the switch 4. The power amplifier 6a is connected to an input terminal (not shown) of the coupler 7 at the subsequent stage. The coupler 7 is connected to an input terminal (not shown) of the isolator 8a. The coupler 7 separates and outputs a part of the input signals RFin_BC0 and RFin_BC3 amplified by the power amplifier 6a to the outside of the circuit module 1 as the output signal Coupler out, and outputs the input signals RFin_BC0 and RFin_BC3 to the isolator 8a in the subsequent stage. Output. The isolator 8a is a nonreciprocal circuit element that outputs the input signals RFin_BC0 and RFin_BC3 to the subsequent switch 9 and does not output the signal reflected from the switch 9 side to the coupler 7 side. Details of the isolator 8a will be described later. The switch 9 outputs one of the input signals RFin_BC0 and RFin_BC3 output from the isolator 8a to the outside of the circuit module 1 as output signals RFout_BC0 and RFout_BC3.

  The transmission path R2 amplifies the input signal RFin_BC6 (1900 MHz band) and outputs it as an output signal RFout_BC6 (1900 MHz band). The transmission path R2 includes a SAW filter 3c, a power amplifier 6b, and an isolator 8b. The SAW filter 3c, the power amplifier 6b, and the isolator 8b are electronic components mounted on the circuit board 2 as shown in FIGS.

  The SAW filter 3c is a bandpass filter that passes only a signal having a predetermined frequency. An input signal RFin_BC6 is input to the SAW filter 3c.

  The power amplifier 6b amplifies the input signal RFin_BC6 output from the SAW filter 3c. The isolator 8b is a nonreciprocal circuit element that outputs the input signal RFin_BC6 to the outside of the circuit module 1 and does not output the signal reflected from the outside of the circuit module 1 to the power amplifier 6b side. Details of the isolator 8b will be described later.

(Configuration of isolator)
Hereinafter, the isolators 8a and 8b will be described with reference to the drawings. FIG. 4 is an external perspective view of the isolators 8a and 8b. FIG. 5 is an external perspective view of the ferrite 32 provided with the center electrodes 35 and 36. FIG. 6 is an external perspective view of the ferrite 32. FIG. 7 is an exploded perspective view of the core isolators 30a and 30b.

  The isolator 8 (8a, 8b) is a lumped constant type isolator and includes a circuit board 2, a core isolator 30 (30a, 30b), capacitors C1, C2, CS1, CS2 and a resistor R as shown in FIG. ing.

  As shown in FIG. 4, the core isolator 30 includes a ferrite 32 and a pair of permanent magnets 41. The core isolator 30 refers to a portion composed only of the ferrite 32 and the permanent magnet 41. As shown in FIG. 5, the ferrite 32 is provided with center electrodes 35 and 36 that are electrically insulated from each other on the front and back main surfaces 32a and 32b. Here, the ferrite 32 has a rectangular parallelepiped shape having parallel main surfaces 32a and 32b facing each other.

  The permanent magnet 41 is bonded to the main surfaces 32a and 32b via, for example, an epoxy adhesive 42 so as to apply a DC magnetic field to the ferrite 32 in a direction substantially perpendicular to the main surfaces 32a and 32b. (See FIG. 7). The main surface 41 a of the permanent magnet 41 has the same dimensions as the main surfaces 32 a and 32 b of the ferrite 32. And the ferrite 32 and the permanent magnet 41 are arrange | positioned so that the external shape of main surface 32a, 32b and the external shape of the main surface 41a may oppose.

  The center electrode 35 is a conductor film provided on the surface of the ferrite 32. That is, as shown in FIG. 5, the center electrode 35 is inclined at a relatively small angle with respect to the long side at the upper left in a state where the main surface 32 a of the ferrite 32 rises from the lower right and branches into two. The center electrode 35 rises to the upper left and wraps around the main surface 32b via the relay electrode 35a on the upper surface 32c. Furthermore, the center electrode 35 is provided so as to branch into two on the main surface 32b so as to overlap with the main surface 32a in a transparent state. One end of the center electrode 35 is connected to a connection electrode 35b formed on the lower surface 32d. The other end of the center electrode 35 is connected to a connection electrode 35c formed on the lower surface 32d. As described above, the center electrode 35 is wound around the ferrite 32 by one turn. The center electrode 35 and the center electrode 36 described below cross each other in an insulated state by providing an insulating film therebetween. The crossing angle of the center electrodes 35 and 36 is set as necessary, and input impedance and insertion loss are adjusted.

  The center electrode 36 is a conductor film provided on the surface of the ferrite 32. The center electrode 36 is formed in a state where the 0.5th turn 36a is inclined at a relatively large angle with respect to the long side from the lower right to the upper left on the main surface 32a and intersects the center electrode 35, and is relayed on the upper surface 32c. The first turn 36c is formed so as to intersect the center electrode 35 substantially perpendicularly on the main surface 32b. The lower end of the first turn 36c goes around the main surface 32a via the relay electrode 36d on the lower surface 32d, and the 1.5th turn 36e intersects the center electrode 35 in parallel with the 0.5th turn 36a on the main surface 32a. And is formed around the main surface 32b via the relay electrode 36f on the upper surface 32c. Similarly, the second turn 36g, the relay electrode 36h, the 2.5th turn 36i, the relay electrode 36j, the third turn 36k, the relay electrode 36l, the 3.5th turn 36m, the relay electrode 36n, the fourth turn The eyes 36o are formed on the surface of the ferrite 32, respectively. Further, both ends of the center electrode 36 are connected to connection electrodes 35c and 36p formed on the lower surface 32d of the ferrite 32, respectively. The connection electrode 35 c is shared as a connection electrode at each end of the center electrode 35 and the center electrode 36.

  Further, the connection electrodes 35b, 35c, and 36p and the relay electrodes 35a, 36b, 36d, 36f, 36h, 36j, 36l, and 36n are concave portions 37 formed on the upper surface 32c and the lower surface 32d of the ferrite 32 (see FIG. 6). It is provided by applying or filling an electrode conductor such as silver, silver alloy, copper, or copper alloy. The upper surface 32c and the lower surface 32d are also provided with a recess 38 parallel to the various electrodes, and are provided with dummy electrodes 39a, 39b, 39c. This type of electrode is formed by forming a through hole in the mother ferrite substrate in advance, filling the through hole with an electrode conductor, and then cutting at a position where the through hole is divided. Various electrodes may be formed as conductor films in the recesses 37 and 38.

  As the ferrite 32, YIG ferrite or the like is used. The center electrodes 35 and 36 and various electrodes can be formed as a thick film or thin film of silver or a silver alloy by a method such as printing, transfer, or photolithography. As the insulating film of the center electrodes 35 and 36, a dielectric thick film such as glass or alumina, a resin film such as polyimide, or the like can be used. These can also be formed by methods such as printing, transfer, and photolithography.

  The ferrite 32 can be integrally fired with a magnetic material including an insulating film and various electrodes. In this case, Pd, Ag or Pd / Ag that can withstand high-temperature firing of various electrodes is used.

  As the permanent magnet 41, a strontium-based, barium-based, or lanthanum-cobalt-based ferrite magnet is usually used. As the adhesive 42 for adhering the permanent magnet 41 and the ferrite 32, it is optimal to use a one-component thermosetting epoxy adhesive.

  The circuit board 2 is made of the same material as that of a normal printed circuit board. On the surface of the circuit board 2, as shown in FIG. 4, terminal electrodes 21a, 21b, 21c, 22a to 22j for mounting a core isolator 30, capacitors C1, C2, CS1, and CS2 and a resistor R are used for input / output. An electrode, a ground electrode (not shown), and the like are provided.

  The core isolator 30 is mounted on the circuit board 2. Specifically, the connection electrodes 35b, 35c, and 36p on the lower surface 32d of the ferrite 32 are integrated by reflow soldering with the terminal electrodes 21a, 21b, and 21c on the circuit board 2, and the lower surface of the permanent magnet 41 is The circuit board 2 is integrated with an adhesive. Thereby, the core isolator 30 is mounted on the circuit board 2 so that the DC magnetic field applied to the ferrite by the permanent magnet 41 is parallel to the main surface of the circuit.

  Capacitors C1, C2, CS1, CS2 and resistor R are reflow soldered to terminal electrodes 22a-22j on circuit board 2. The core isolator 30, capacitors C1, C2, CS1, CS2 and resistor R are mounted on the circuit board 2 as shown in FIG. 3 (reference numerals of the capacitors C1, C2, CS1, CS2 are omitted in FIG. 3). . The core isolator 30, the capacitors C1, C2, CS1, CS2, and the resistor R are connected by wiring in the circuit board 2, thereby constituting isolators 8a, 8b. On the other hand, the SAW filters 3a to 3c, the switch 4, the power amplifier 6a, the coupler 7, and the switch 9 mounted on the circuit board 2 are electronic components that do not constitute the isolators 8a and 8b.

(Isolator circuit configuration)
Next, circuit configurations of the isolators 8a and 8b will be described with reference to the drawings. FIG. 8 is an equivalent circuit diagram of the isolators 8a and 8b.

  The input port P1 is connected to the capacitor C1 and the resistor R via the capacitor CS1. The capacitor CS <b> 1 is connected to one end of the center electrode 35. The other end of the center electrode 35 and one end of the center electrode 36 are connected to the resistor R and the capacitors C1 and C2, and to the output port P2 via the capacitor CS2. The other end of the center electrode 36 and the capacitor C2 are connected to the ground port P3.

  In the isolators 8a and 8b composed of the above equivalent circuits, one end of the center electrode 35 is electrically connected to the input port P1, the other end is electrically connected to the output port P2, and one end of the center electrode 36 is connected to the output port P2. Since the other end is electrically connected to the ground port P3, a two-port lumped constant isolator with low insertion loss can be obtained.

  Further, the core isolator 30 is mechanically stable because the ferrite 32 and the pair of permanent magnets 41 are integrated with the adhesive 42, and is a robust isolator that is not deformed or damaged by vibration or impact.

(Yoke configuration)
Incidentally, the isolator 8 does not have a yoke. For this reason, the magnetic field generated by the core isolator 30 may leak out of the isolator 8 and adversely affect electronic components mounted on the circuit board 2. Furthermore, the magnetic field generated by the core isolator 30 may leak out of the circuit board 2 and adversely affect electronic components provided outside the circuit board 2.

  Therefore, the circuit module 1 includes a metal case 50 and yokes 60a and 60b as shown in FIG. The metal case 50 is a covering that is provided on the circuit board 2 and covers the SAW filters 3a to 3c, the switch 4, the power amplifiers 6a and 6b, the coupler 7, the isolators 8a and 8b, and the switch 9. Specifically, as shown in FIG. 3, the metal case 50 has a rectangular parallelepiped box shape with an open bottom, and includes SAW filters 3 a to 3 c, a switch 4, power amplifiers 6 a and 6 b, a coupler 7, The isolators 8a and 8b and the switch 9 are attached to the circuit board 2 so as to cover the main surface of the circuit board 2 mounted thereon. A ground potential is applied to the metal case 50 via the circuit board 2.

  The yokes 60a and 60b are ferromagnetic members (for example, soft iron) provided so as to overlap the core isolators 30a and 30b when viewed in plan from the normal direction of the circuit board 2, respectively. The yokes 60a and 60b are provided on a surface parallel to the main surface of the circuit board 2 in the metal case 50 so as to face the core isolators 30a and 30b. That is, the yokes 60 a and 60 b are attached to the inner peripheral surface side of the top surface of the metal case 50 with an adhesive or the like.

(effect)
In the circuit module 1 configured as described above, adverse effects caused by the magnetic field of the core isolators 30a and 30b on the electronic components arranged around the core isolators 30a and 30b can be reduced. FIG. 9 is a sectional structural view of the circuit module 1 of FIG. Hereinafter, the core isolator 30b will be described as an example with reference to FIG.

  In the core isolator 30b, as shown in FIG. 4, the permanent magnet 41 applies a DC magnetic field to the main surfaces 32a and 32b in a direction substantially perpendicular to the ferrite 32. The core isolator 30 b is mounted on the circuit board 2 so that the direction of the DC magnetic field is parallel to the main surface of the circuit board 2. Therefore, when the yoke 60b is not provided, the magnetic field B ′ generated by the core isolator 30b is generated so as to extend along the main surface of the circuit board 2 as shown in FIG. In this case, the magnetic field B ′ penetrates through the power amplifier 6b. Further, the magnetic field B ′ passes through the metal case 50 and leaks out of the circuit module 1. Accordingly, the magnetic field B ′ may spread to electronic components provided outside the circuit module 1.

  Therefore, in the circuit module 1, a yoke 60b using a ferromagnetic member is provided. As a result, the magnetic field B passes through the vicinity of the yoke 60b having a small magnetic resistance. The yoke 60b is provided so as to overlap the core isolator 30b when viewed in plan from the normal direction of the circuit board 2. Therefore, the magnetic field B is generated relatively small without making a large rotation like the magnetic field B ′. That is, the magnetic field B proceeds upward as soon as it exits the isolator 8b, and immediately proceeds downward after passing through the yoke 60b, and returns to the isolator 8b. Thereby, the magnetic field B does not extend along the circuit board 2 like the magnetic field B ′, so that the spread to the power amplifier 6b and the like is reduced. Furthermore, since the magnetic field B returns to the core isolator 30b after passing through the yoke 60b, it does not leak out of the metal case 50. Therefore, the spread of the magnetic field B to the electronic components provided outside the circuit module 1 is reduced.

  In the circuit module 1, yokes 60 a and 60 b are provided inside the metal case 50. Therefore, the magnetic field B can be generated more narrowly. As a result, the influence on the characteristics of the power amplifier 6b due to the spread of the magnetic field B to the power amplifier 6b and the like is more effectively reduced, and the leakage of the magnetic field B to the outside of the circuit module 1 is more effectively reduced. .

  In the circuit module 1, a ground potential is applied to the metal case 50. Thereby, it is possible to suppress the noise generated in the circuit module 1 from being radiated to the outside of the circuit module 1 and to suppress the noise from the outside of the circuit module 1 from entering the circuit module 1.

  Further, in the circuit module 1, the provision of the yokes 60a and 60b suppresses the leakage of the magnetic field outside the circuit module 1. Therefore, the metal case 50 does not need to be made of a material for suppressing the leakage of the magnetic field. Therefore, the metal case 50 can be made from an inexpensive material.

  Further, in the circuit module 1, since the distance between the core isolators 30a and 30b and the yokes 60a and 60b can be increased as will be described below, excellent insertion loss characteristics and isolation characteristics of the isolator 8 can be obtained.

  The inventor of the present application investigated the relationship between the distance L (see FIG. 9) between the core isolators 30a and 30b and the yokes 60a and 60b and the insertion loss characteristics and isolation characteristics of the isolators 8a and 8b by computer simulation. Specifically, the inventor of the present application caused the computer to calculate the insertion loss characteristic and the isolation characteristic when the distance L was changed to 0.05 mm, 0.10 mm, 0.15 mm, and ∞. FIG. 10 is a graph showing the insertion loss characteristics of the isolator 8. The vertical axis represents the attenuation, and the horizontal axis represents the frequency. FIG. 11 is a graph showing the isolation characteristics of the isolator 8. The vertical axis represents the attenuation, and the horizontal axis represents the frequency. The insertion loss characteristic is a frequency characteristic of a signal passing from the input port P1 to the output port P2 in the equivalent circuit of FIG. 8, and the isolation characteristic is a frequency of a signal passing from the output port P2 to the input port P1. It is a characteristic. The isolator 8 is required to have the insertion loss as small as possible and the isolation as large as possible at a desired frequency.

  As shown in FIGS. 10 and 11, it can be seen that as the distance L increases, the insertion loss characteristic and the isolation characteristic are improved. Therefore, it is desirable to arrange the core isolators 30a and 30b and the yokes 60a and 60b as far apart as possible. Therefore, by attaching the yokes 60a, 60b to the metal case 50 as in the circuit module 1, the core isolators 30a, 30b and the yokes 60a, 60b are compared to the case where the yokes 60a, 60b are directly provided on the core isolators 30a, 30b. The distance L with respect to 60b can be increased. As described above, the circuit module 1 can obtain excellent insertion loss characteristics and isolation characteristics.

(First modification)
The circuit module according to the first modification will be described below with reference to the drawings. FIG. 12 is a cross-sectional structure diagram of a circuit module 1a according to a first modification.

  In the circuit module 1 a, a recess G is provided on a surface of the metal case 50 that is parallel to the circuit board 2 and faces the circuit board 2. The yokes 60a and 60b are mounted in the recess G as shown in FIG. Accordingly, the distance L between the core isolators 30a and 30b and the yokes 60a and 60b can be increased without forming protrusions by the yokes 60a and 60b on the outer peripheral surface of the metal case 50.

(Second modification)
The circuit module according to the second modification will be described below with reference to the drawings. FIG. 13 is a cross-sectional structure diagram of a circuit module 1b according to a second modification.

  In the circuit module 1 b, a concave portion G is provided on a surface of the metal case 50 that is parallel to the circuit board 2 and opposite to the surface facing the circuit board 2. The yokes 60a and 60b are attached in the recess G as shown in FIG. Accordingly, the distance L between the core isolators 30a and 30b and the yokes 60a and 60b can be increased without forming protrusions by the yokes 60a and 60b on the outer peripheral surface of the metal case 50.

(Third Modification)
Hereinafter, a circuit module according to a third modification will be described with reference to the drawings. FIG. 14 is a cross-sectional structure diagram of a circuit module 1c according to a third modification.

  In the circuit module 1c, a convex portion P that protrudes toward the core isolators 30a and 30b is provided on the surface of the metal case 50 that is parallel to the circuit board 2 and faces the circuit board 2. And the yokes 60a and 60b are attached to the front-end | tip of the convex part P, as shown in FIG. Thereby, by adjusting the height of the convex portion P, the distance L between the core isolators 30a and 30b and the yokes 60a and 60b can be adjusted to an optimum size.

(Fourth modification)
Hereinafter, a circuit module according to a fourth modification will be described with reference to the drawings. FIG. 15 is a cross-sectional structure diagram of a circuit module 1d according to a fourth modification.

  In the circuit module 1d, an insulating resin 70 is provided as a covering instead of the metal case 50 as shown in FIG. Specifically, the insulating resin 70 is, for example, an epoxy resin, and is provided so as to cover the surface on which the core isolators 30a and 30b of the circuit board 2 are mounted. The insulating resin 70 is formed by dripping and curing the resin on the circuit board 2 after the mounting of the electronic components such as the core isolator 30 on the circuit board 2 is completed. The yokes 60 a and 60 b are provided on the upper surface of the insulating resin 70.

  When the metal case 50 is used, a shallow concave portion G cannot be formed in the metal case 50 due to a problem in metal processing, or if the concave portion G of the metal case 50 is too shallow due to processing variation, The distance between the case 50 and the parts including the isolator 8 varies, and the variation of the circuit modules is large. However, when a resin is used, a thin resin film can be formed with high accuracy by optimizing the coating method and the like. Therefore, according to the circuit module 1d, it is possible to reduce the height as compared with the circuit modules 1, 1a to 1c in which the metal case 50 is used. Further, since the yokes 60a and 60b can be formed by screen printing or the like, the yokes 60a and 60b can be formed in a desired shape.

(Fifth modification)
Hereinafter, a circuit module according to a fifth modification will be described with reference to the drawings. FIG. 16 is a cross-sectional structure diagram of a circuit module 1e according to a fifth modification.

  In the circuit module 1 e, a plurality of layers of insulating resins 70 a and 70 b are laminated in the normal direction of the circuit board 2. The yokes 60a and 60b are provided between the insulating resins 70a and 70b. Thereby, by adjusting the thickness of the insulating resin 70a, the distance L between the core isolators 30a and 30b and the yokes 60a and 60b can be adjusted to an arbitrary size.

(Sixth Modification)
The circuit module according to the sixth modification will be described below with reference to the drawings. FIG. 17 is a cross-sectional structure diagram of a circuit module 1f according to a sixth modification.

  In the circuit module 1f, the yokes 60a and 60b have an upper surface 61a and side surfaces 61b and 61c, respectively. The side surfaces 61b and 61c are bent downward with respect to the upper surface 61a. The upper surface 61a is provided on the upper surface of the insulating resin 70, and the side surfaces 61b and 61c are provided in the insulating resin 70 and face the side surfaces of the core isolators 30a and 30b. As a result, the magnetic fields generated by the core isolators 30a and 30b are more effectively suppressed from extending along the circuit board 2.

  The side surfaces 61b and 61c are produced, for example, by the following procedure. First, grooves G1 and G2 are formed on the upper surface of the insulating resin 70 by a dicer. The depths of the grooves G1 and G2 are depths that do not reach the circuit board 2. Next, the ferromagnetic paste is filled into the grooves G1 and G2 by screen printing to form the side surfaces 61b and 61c. The upper surface 61a may be formed simultaneously with the formation of the side surfaces 61b and 61c.

(Seventh Modification)
The circuit module according to the seventh modification will be described below with reference to the drawings. FIG. 18 is a cross-sectional structure diagram of a circuit module 1g according to a seventh modification.

  In the circuit module 1g, the yokes 60a and 60b are provided on the main surface of the circuit board 2 opposite to the main surface on which the core isolators 30a and 30b are mounted. Thereby, it can suppress that a magnetic field leaks to the lower side of the circuit board 2. FIG.

(Eighth modification)
Hereinafter, a circuit module according to an eighth modification will be described with reference to the drawings. FIG. 19 is a cross-sectional structure diagram of a circuit module 1h according to an eighth modification.

  In the circuit module 1h, the yokes 60a and 60b are not provided. Instead, the circuit module 1h is provided with an insulating resin 80 mixed with a ferromagnetic material. The insulating resin 80 is provided so as to cover the surface of the circuit board 2 on which the core isolators 30a and 30b are mounted. Thus, the core isolators 30a and 30b are covered with the insulating resin 80 mixed with the ferromagnetic material. Even with the configuration as described above, similarly to the circuit modules 1 and 1a to 1g, it is possible to reduce the adverse effect of the magnetic field of the core isolator 30 on the electronic components arranged around the core isolator 30.

  In the circuit modules 1 and 1a to 1g, the yokes 60a and 60b may be provided so as to face the entire surface of the circuit board 2.

  As described above, the present invention is useful for a circuit module, and particularly in a circuit module on which an isolator having no yoke is mounted, an adverse effect due to the magnetic field of the isolator on an electronic component arranged around the isolator is reduced. It is excellent in that it can

C1, C2, CS1, CS2 Capacitor P1 Input port P2 Output port P3 Ground port 1, 1a to 1h Circuit module 2 Circuit board 3a to 3c SAW filter 4, 9 Switch 6a, 6b Power amplifier 7 Coupler 8a, 8b Isolator 30a, 30b Core isolator 32 Ferrite 35, 36 Center electrode 41 Permanent magnet 50 Metal case 60a, 60b Yoke 70, 70a, 70b, 80 Insulating resin

Claims (6)

A circuit board;
A ferrite, a permanent magnet for applying a DC magnetic field to the ferrite, a first center electrode provided on the ferrite, having one end electrically connected to the input port and the other end connected to the output port; A core isolator having a second center electrode provided on the ferrite so as to intersect the first center electrode in an insulated state, having one end connected to the output port and the other end connected to the ground port. A core isolator mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board;
A first electronic component constituting an isolator together with the core isolator, wherein the first electronic component is mounted on the circuit board;
A second electronic component that does not constitute the isolator, the second electronic component mounted on the circuit board;
A ferromagnetic member provided so as to overlap the core isolator when viewed from the normal direction of the circuit board;
A covering provided on the circuit board so as to cover the core isolator;
Equipped with a,
The ferromagnetic member is provided on the covering,
The covering is a metal case;
The ferromagnetic member is provided on a surface parallel to the main surface of the circuit board in the metal case so as to face the core isolator,
On the surface parallel to the main surface of the circuit board in the metal case, a convex portion protruding toward the core isolator is formed,
The ferromagnetic member is provided on the convex portion;
A circuit module characterized by The metal case covers the core isolator, the first electronic component and the second electronic component;
The circuit module according to claim 1 . A ground potential is applied to the metal case,
The circuit module according to claim 1 or claim 2, characterized in. A circuit board;
A ferrite, a permanent magnet for applying a DC magnetic field to the ferrite, a first center electrode provided on the ferrite, having one end electrically connected to the input port and the other end connected to the output port; A core isolator having a second center electrode provided on the ferrite so as to intersect the first center electrode in an insulated state, having one end connected to the output port and the other end connected to the ground port. A core isolator mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board;
A first electronic component constituting an isolator together with the core isolator, wherein the first electronic component is mounted on the circuit board;
A second electronic component that does not constitute the isolator, the second electronic component mounted on the circuit board;
A ferromagnetic member provided so as to overlap the core isolator when viewed from the normal direction of the circuit board;
A covering provided on the circuit board so as to cover the core isolator;
Equipped with a,
The ferromagnetic member is provided on the covering which is an insulating resin,
The insulating resin is laminated in a plurality of layers in the normal direction of the circuit board,
The ferromagnetic member is provided between layers of the insulating resin;
A circuit module characterized by A circuit board;
A ferrite, a permanent magnet for applying a DC magnetic field to the ferrite, a first center electrode provided on the ferrite, having one end electrically connected to the input port and the other end connected to the output port; A core isolator having a second center electrode provided on the ferrite so as to intersect the first center electrode in an insulated state, having one end connected to the output port and the other end connected to the ground port. A core isolator mounted on the circuit board so that the direction of the DC magnetic field is parallel to the main surface of the circuit board;
A first electronic component constituting an isolator together with the core isolator, wherein the first electronic component is mounted on the circuit board;
A second electronic component that does not constitute the isolator, the second electronic component mounted on the circuit board;
A ferromagnetic member provided so as to overlap the core isolator when viewed from the normal direction of the circuit board;
A covering provided on the circuit board so as to cover the core isolator;
Equipped with a,
The ferromagnetic member is provided on the covering which is an insulating resin,
The ferromagnetic member has a portion provided in the insulating resin and facing a side surface of the core isolator;
A circuit module characterized by The second electronic component is a power amplifier;
The circuit module according to any one of claims 1 to 5, characterized in.

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