JP2006211620A - Filter and duplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a thermal resistance difference between a signal terminal and a reference potential terminal while excellently keeping filter characteristics in a filter and a duplexer, and to improve the reliability of soldering at the time of mounting. <P>SOLUTION: The filter or the duplexer is provided with the signal terminal for external connection, the reference potential terminal and a common reference potential part electrically connected with the reference potential terminal, which are all formed of conductors, on one surface of a package, and a slit part for partially separating the common reference potential part and the reference potential terminal is provided between the common reference potential part and the reference potential terminal. The common reference potential part is formed over the almost entire one surface of the package, the slit part and a bridging part composed of the conductor are provided between the common reference potential part and the reference potential terminal, and the reference potential terminal is formed of solder resist. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a filter and a duplexer, and more particularly to a structure of an external connection terminal provided on a bottom surface of a package of these devices.

  Surface mounting technology is widely used for mounting electronic components in order to realize small size, high density, high performance, and low cost of electronic devices. In this technology, component terminals are fixed to the connection pads on the surface of the printed wiring board with solder. For example, filters and duplexers used in various communication devices such as mobile phones have recently been based on this technology. It is often manufactured as a surface mount device (SMD).

  14 and 15 are each a bottom view showing an example of a conventional duplexer configured as such an SMD. As shown in FIG. 14, in the conventional duplexer, external connection terminals that are solder-connected to connection pads of a printed wiring board (mounting substrate) to be mounted are provided on the bottom surface of the package. These external connection terminals include a signal terminal including a transmission terminal 1, a reception terminal 2, and an antenna terminal 3, and a reference potential terminal 4 connected to a reference potential terminal of the mounting board.

  In the example shown in FIG. 15, a conductor layer is provided on substantially the entire bottom surface of the package excluding the signal terminal portion, and each reference potential terminal 4 and these reference potential terminals 4 are electrically connected to each other by this conductor layer. A reference potential portion 5 is formed. In addition, in order to limit the area | region to which each reference potential terminal 4 is soldered, each area | region which should form a reference potential terminal is extracted (except), and the soldering resist (not shown) is provided on the surface of the said conductor layer. It may be formed by coating.

  By the way, in order to obtain the designed original electrical characteristics (filter characteristics), it is necessary to make the electrical reference potential of the filter and duplexer parts as identical as possible to the ground potential of the printed wiring board to be mounted. Is necessary. For example, when there is an inductance component between the ground potential of the printed wiring board to be mounted and the reference potential of the filter, the potential difference between the two increases as the frequency increases, and the original filter performance cannot be achieved. There is. In particular, with the recent increase in signal frequency, its importance is great.

  For this reason, a common reference potential portion that electrically connects the reference potential terminals of the filter components is provided in the filter package. In this way, the inductance and resistance inside the filter component can be reduced by the parallel effect. In this case, the reference potential terminals are connected so as to minimize the inductance and resistance as much as possible. Also, the reference potential terminal on the printed wiring board side where the filter components are mounted may actually vary in the potential of each terminal due to restrictions on the area and shape of the wiring board. In order to eliminate or reduce the influence of variations in the reference potential, it is effective to provide a common reference potential portion in the filter component.

  16 to 22 are schematic diagrams for explaining this. First, the device shown in FIG. 16 includes a filter element 7 on the upper surface of the package substrate 6. A reference potential terminal of the element 7 and a reference potential terminal 4 for external connection provided on the bottom surface of the package substrate 6 are connected to the via hole 8. And the package does not have a common reference potential portion. The reference terminal 4 for external connection is connected to the reference potential terminal 11 of the mounting substrate 10 via the solder 9.

In such a device structure, as shown in FIG. 17, a parasitic inductance component L ₀ caused by the via hole 8 is generated between the filter element 7 and the reference potential surface of the mounting substrate. Even with some other connection method, an inductance component is generated. Therefore, the reference potential surface of the filter element 7 is in a high impedance state with respect to the reference potential surface of the package. In particular, as the frequency increases, the impedance increases. In the case of a filter based on the principle that signal power is consumed by grounding, the attenuation characteristic of the filter is structurally degraded as compared with the structure of FIG. Further, when there is a potential deviation in the reference potential terminal on the printed wiring board side mounted as described above, a potential difference is generated in the reference potential terminal of the filter element 7 as shown in FIG. In this case, the operation of the filter element 7 has a structure different from the design condition. For this reason, the electrical characteristics (particularly the attenuation characteristics) of the filter are more susceptible to the influence on the mounting board side (parasitic inductance component L _{1 of the} mounting board) than the structure of FIG.

The filter shown in FIG. 20 includes a common reference potential portion 12 inside the package substrate 6 in the filter component. In this filter component, the reference potential terminal 4 of the filter element 7 is electrically connected to each other by the common reference potential portion 12, and thus is less susceptible to the influence of the reference potential deviation on the mounting substrate side. However, the distance (e.g., via holes 8a) is present between the common reference potential section 12 and the external connection terminal 4, the parasitic inductance component L ₂ by which as shown in FIG. 20 occurs.

Further, the filter shown in FIG. 21 is provided with a common reference potential portion 5 on the bottom surface of the filter component (package substrate 6) as in the example shown in FIG. According to this device structure, as shown in FIG. 22, the reference potential terminals 4 of the filter elements 7 are electrically connected to each other by the common reference potential portion 5, and the common reference potential portion 5 is closest to the mounting substrate 10. Since it is formed at the position, it is advantageous in that it is hardly affected by the reference potential deviation on the mounting substrate side and the parasitic inductance component in the device is small. Further, if the common reference potential portion 5 is formed over substantially the entire bottom surface of the filter component as shown in FIG. 15, the parasitic inductance component L ₃ of the common reference potential portion 5 that connects the reference potential terminals 4 to each other is maximized. It can be kept small.

  On the other hand, the terminal structures as shown in FIGS. 15 and 21 are good structures from the viewpoint of the electrical characteristics of the filter, but there is a large difference in thermal resistance between the signal terminals 1 to 3 and the reference potential terminal 4. There is room for improvement in terms of reliability of solder joints with the mounting board during solder mounting.

  More specifically, in the structure of FIG. 15, the reference potential terminal 4 is integrally connected to a conductor portion (common reference potential portion 5) having a large area covering substantially the entire bottom surface. While the thermal resistance is small, the signal terminals 1 to 3 are separated from the conductor portion 5 and are small and isolated, and therefore the thermal resistance is large. Therefore, for example, when heated in a reflow furnace, each of the terminals 1 to 4 does not have a uniform temperature, and the signal terminals 1 to 3 are less likely to be heated than the reference potential terminal 4 and are likely to have poor bonding.

  In particular, in the case of a filter, the number of reference potential terminals 4 is usually larger than the number of signal terminals 1 to 3, and therefore the thermal resistance difference between the signal terminals 1 to 3 and the reference potential terminal 4 tends to become more prominent. It is in.

  Therefore, an object of the present invention is to reduce the thermal resistance difference between the signal terminal and the reference potential terminal while maintaining good electrical characteristics (filter characteristics) in the filter and duplexer, and to improve the reliability of soldering during mounting. The point is to improve.

  In order to achieve the above object and solve the problem, the filter according to the present invention includes a signal terminal for external connection, a reference potential terminal for external connection, both formed of a conductor on one surface of the package, A filter including a common reference potential portion electrically connected to the reference potential terminal for external connection, and the common reference potential portion and the reference potential terminal between the common reference potential portion and the reference potential terminal A slit portion for partially separating the reference potential terminal was provided.

  According to the filter structure of the present invention, the reference potential terminal formed of a good heat conductor is partially separated from the common reference potential portion by the slit portion provided between the common reference potential portion and the reference potential terminal. Therefore, the thermal resistance from the reference potential terminal of the printed circuit board to be mounted is increased, and the thermal resistance value of the signal terminal provided on the package surface is electrically (= thermally) separated from the other reference potential terminals. I can do it. Therefore, the difference in thermal resistance between the reference potential terminal and the signal terminal is reduced, the temperature of each terminal during mounting can be made more uniform, and the reliability of solder joint can be improved.

  The filter includes various filters provided with a ground electrode such as a surface acoustic wave (SAW) filter or an LC filter. The same applies to the following duplexer.

  In addition, the duplexer according to the present invention includes a signal terminal for external connection, a reference potential terminal for external connection, a reference potential terminal for external connection, and an electrical connection, which are all formed of a conductor on one surface of the package. A duplexer having a common reference potential portion connected to each other, wherein the common reference potential portion and the reference potential terminal are partially separated between the common reference potential portion and the reference potential terminal A slit portion is provided.

  Even with such a duplexer structure, it is possible to improve the reliability of solder joints at the time of mounting as in the case of the filter.

  In the filter or duplexer, the common reference potential portion is formed over substantially the entire surface of one side of the package excluding the signal terminal forming portion and is electrically connected to the reference potential terminal. In addition, between the common reference potential portion and the reference potential terminal, the slit portion and a bridge portion made of a conductor that is electrically connected to the common reference potential portion and the reference potential terminal are formed, The reference potential terminal may be defined by a solder resist disposed on one surface of the package.

  According to such a filter or duplexer, each reference potential terminal is electrically connected by the bridge portion so that it is difficult to be influenced by the reference potential deviation of the mounting substrate, and the common reference potential portion is not connected to the package. By forming over substantially the entire area of one surface, it is possible to keep the parasitic inductance component in the filter component small. Further, the formation of the slit portion can reduce the difference in thermal resistance between the reference potential terminal and the signal terminal, and can improve the reliability of solder joint during mounting.

  In the present invention, the constituent material of the package is not limited, and may be, for example, a resin, a composite material in which an inorganic material is mixed with the resin, ceramics, or the like. However, since the heat resistance of the resin material is larger than that of the ceramic material or the like, the present invention is particularly advantageous when applied to a filter component having a resin package.

  According to the present invention, while maintaining the electrical characteristics (filter characteristics) of the filter and the duplexer satisfactorily, the thermal resistance difference between the signal terminal and the reference potential terminal is reduced to improve the soldering reliability during mounting. I can do it.

  Other objects, features, and advantages of the present invention will become apparent from the following description of embodiments of the present invention based on the drawings. It should be noted that the present invention is not limited to the following embodiments, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims. Moreover, in each figure, the same code | symbol shows the same or an equivalent part.

  FIG. 1 shows a duplexer according to an embodiment of the present invention. As shown in the figure, the duplexer 21 includes a transmission filter element 24 and a reception filter element 25 mounted on the upper surface of a substrate 22, and the filter elements 24 and 25 are sealed with a lid 23. It is. A common GND portion (common reference potential portion) 35 that electrically connects each reference potential terminal (hereinafter referred to as GND terminal) in the duplexer is provided on the bottom surface of the substrate 22, and further mounted on the surface (lower surface). A solder resist (solder mask) 40 is disposed to prevent a short circuit due to soldering and to define the GND terminal 4 on the bottom surface of the package.

  2 and 3 show the bottom surface of the duplexer. FIG. 2 shows a state where the solder resist 40 is removed, and FIG. 3 shows a state where the solder resist 40 is arranged. FIG. 4 is an enlarged view of a bottom terminal portion (a slit described later).

  As shown in FIG. 2, a plurality of external connection terminals 1 to 4 that are solder-connected to connection pads of a substrate (mounting substrate) on which the duplexer 21 is to be mounted are provided on the bottom surface of the substrate 22. These external connection terminals 1 to 4 include a signal terminal including a transmission terminal 1, a reception terminal 2, and an antenna terminal 3, and a GND terminal 4. The GND terminal 4 is connected to a GND terminal (connection pad) of the mounting board. The signal terminals 1 to 3 are respectively connected to corresponding connection pads on the mounting board. The filter elements 24 and 25 and other circuit elements provided in the duplexer 21 are electrically connected to the external connection terminals 1 to 4 through via holes, castellations (side vias) 26, and the like.

  In addition, a conductor layer is provided on substantially the entire bottom surface of the base substrate excluding the arrangement portion of the signal terminals 1 to 3, and the GND terminals 4 and the GND terminals 4 are electrically connected to each other by the conductor layer. A GND portion 35 is formed.

  The GND terminal 4 is integrally formed from the same conductor foil (the above-mentioned conductor layer) as the common GND part 35, and the peripheral part of the GND terminal 4 (the boundary part between the GND terminal 4 and the common GND part 35) is described later. However, a slit 36 that partially divides between the GND terminal 4 and the common GND portion 35 is provided at the peripheral portion of each GND terminal 4. Of the peripheral portion of the GND terminal, the portion where the slit 36 is not formed is left connected by the conductor layer, thereby forming a bridging portion 37 that electrically connects the GND terminal 4 and the common GND portion 35. .

  The dimensions of the slit 36 and the bridging portion 37 are not particularly limited to these values, but the width W1 (see FIG. 4) of the slit 36 is, for example, 100 to 200 μm, and the width W2 of the bridging portion 37 is, for example, 50 μm. It can be about.

  As shown in FIG. 3, the solder resist 40 is coated on the surface of the conductor layer over almost the entire area of the bottom surface of the substrate excluding the formation portions of the signal terminals 1 to 3 and the regions where the GND terminals 4 are to be formed. Thus, each GND terminal 4 is formed on the bottom surface of the base substrate so as to cover the conductor layer, and solder is prevented from adhering to portions other than the external connection terminals 1 to 4 at the time of mounting. The shape of the GND terminal can be arbitrarily formed by a solder resist.

  In the present embodiment, since the slit 36 is provided in the peripheral portion of the GND terminal 4 as described above, the thermal resistance of the GND terminal 4 can be increased by restricting the connection portion with the common GND portion 35. The difference in thermal resistance from the signal terminals 1 to 3 provided separately from other conductors on the bottom surface of the base substrate can be reduced. On the other hand, even if the slit 36 is provided, each GND terminal 4 is electrically connected to the common GND part 35 and the other GND terminals 4 by the bridging part 37, so that the influence of the reference potential deviation on the mounting board side is affected. It is hard to receive. Furthermore, since the common GND portion 35 is formed over substantially the entire bottom surface of the device and is provided at a position closest to the mounting substrate, that is, the bottom surface of the device, the parasitic inductance component in the device can be kept small.

[Study on thermal resistance of signal terminal and GND terminal]
(1) Relationship between slit width and difference in thermal resistance between signal terminal and GND terminal The difference in thermal resistance between the signal terminal and the GND terminal will be examined with reference to FIGS. Considering a terminal structure having a common GND portion as shown in FIG. 15 on the bottom surface, the GND terminal is formed integrally with the conductor on the bottom surface of the device, and the thermal resistance of the conductor is very small, whereas the signal terminal is The thermal resistance difference between the signal terminal and the GND terminal with respect to the reference potential terminal of the mounted board is separated from the surrounding conductors and the thermal resistance of the board insulating layer (for example, resin) is much higher than that of the conductor. Can be considered to be caused by the gap around the signal terminal, that is, the thermal resistance of the substrate insulating layer. In other words, if a GND terminal having the same shape as the signal terminal is formed, the difference in thermal resistance can be reduced and made more uniform.

  Therefore, as shown in FIG. 5, the thermal resistance value depends on the width (slit width) of the gap 52 between the signal terminal 51 and the surrounding conductor (common GND portion) 5, and the substrate material is resin, LTCC. The calculation was performed for each of the cases using (Low Temperature Co-fired Ceramics / Low Temperature Co-fired Ceramics) and HTCC (High Temperature Co-fired Ceramics / High Temperature Co-fired Ceramics). The vertical and horizontal dimensions x of the terminals 51 are both 1 mm, and the slit width W1 is 0.2 mm.

FIG. 6 shows a calculation result in the case of a resin substrate. Assuming that a general epoxy resin is used as the resin material and the thermal resistivity is 3.33 [m · K / W], when the slit width W1 is 10 to 500 μm, the thermal resistance value is As shown in the table of FIG. In this table, the heat passage cross-sectional area: 3.00 × 10 ⁻⁶ [m ² ] is calculated assuming that the thickness of the resin substrate at the gap 52 is 1 mm (the same applies hereinafter). FIG. 7 shows the case of the LTCC substrate, in which the thermal resistivity is 0.33 [m · K / W]. Further, FIG. 8 shows the case of the HTCC substrate, and the thermal resistivity is 0.03 [m · K / W]. Further, the relationship between the slit width and the thermal resistance difference is shown by a diagram in FIG.

  As is apparent from these figures, for example, if the tolerance of variation in terminal temperature (thermal resistance) during solder reflow is ± 10 ° C. (10 [K / W]) It can be seen that the width should be less than 10 μm and the slit width should be less than 100 μm even in the case of LTCC materials. In the case of an HTCC-based material, if the slit width is less than 1 mm, the temperature difference between the signal terminal and the GND terminal is almost kept within 10 ° C.

  From these examination results, when the distance width (the slit width) between the signal terminal and the common GND part is 10 μm or more for the resin-based substrate having a large thermal resistance and 100 μm or more for the LTCC substrate, the periphery of the GND terminal It is necessary to reduce the temperature difference (thermal resistance difference) from the signal terminal by providing a slit on the GND terminal to increase the thermal resistance of the GND terminal.

  On the other hand, the distance between a signal terminal and a GND pattern (GND terminal or common GND portion) on the same plane as the signal terminal is generally determined by electrical characteristics and restrictions on the manufacturing process of the substrate.

  In other words, in the case of a filter or duplexer, the distance between the two (the signal terminal and the GND pattern) can be made as large as possible so as to suppress the parasitic capacitance generated due to the distance between the signal terminal and the GND pattern. desirable. In the case of a material having a normal relative dielectric constant (about 3 to 10) as a substrate material, the pattern interval is generally set to about 50 to 300 μm.

  In terms of the manufacturing process, the pattern width / slit width of about 30/30 μm is the limit of thinning at the present time for both resin-based and ceramic-based materials. Therefore, it is difficult from the viewpoint of the manufacturing process to make the gap width around the terminals less than 10 μm and to keep the thermal resistance difference between the terminals within an allowable value.

  The present invention can provide means for reducing the difference in thermal resistance between the signal terminal and the GND terminal without deteriorating the electrical characteristics by securing the distance between the signal terminal and the GND pattern under such circumstances. It is.

(2) Difference in thermal resistance between signal terminal and GND terminal due to difference in terminal structure FIG. 10 is a diagram schematically showing the peripheral structure of the terminal. FIG. 10A shows a slit 52 around the signal terminal 51. When formed, (b) does not form any slit around the GND terminal 4, (c) forms a slit 36 around the GND terminal 4, and (d) shows the GND terminal 4 according to the present invention. The case where the slit 36 and the bridge part 37 were formed in the circumference | surroundings is shown, respectively. The vertical and horizontal dimensions x of the terminals 4 and 51 are both 1 mm, and the slit width W1 is 0.2 mm.

  FIG. 11 is a table showing calculation results of thermal resistance in each of the terminal structures shown in FIGS. As shown in this table, when the slit is formed around the signal terminal (a), the thermal resistance is 222 [K / W], and when the slit is not formed around the GND terminal (b), the thermal resistance is 0. 169 [K / W], when the slit is formed around the GND terminal (c), the thermal resistance is 222 [K / W], when the slit and the bridge are formed around the GND terminal (d) The resistance is 67.26 [K / W].

  Therefore, as shown in FIGS. 10A and 10B, when the slit 52 is provided around the signal terminal and the slit is not provided around the GND terminal, the difference in thermal resistance between the signal and GND terminals is , Approximately 222 (K / W). On the other hand, when the slits 36 are provided in the three directions around the GND terminal as shown in FIG. 10 (d) and the bridging portion 37 is provided in each slit portion, the heat between the signal-GND terminals is provided. The resistance difference can be reduced to 154.74 [K / W].

(3) Relationship between slit width around GND terminal and difference in thermal resistance between signal terminal and GND terminal FIGS. 12 and 13 show signal terminal-GND when a slit having a width of 10 to 500 μm is provided around the GND terminal. It is the table | surface and diagram which show the thermal resistance difference between terminals. In these charts, the thermal resistance difference (right end of the table) is the difference in thermal resistance between the signal terminal and the GND terminal when the slit width around the signal terminal is 200 μm and there is no slit around the GND terminal: 222 [K / W] is a reference value, and the difference from this reference value is calculated for the case where only the slit is formed around the GND terminal and the case where the slit and the bridge are provided. As shown in these figures, when a slit is provided around the GND terminal, the thermal resistance difference is reduced in any case.

(4) Reduction effect of thermal resistance difference by (slit + bridging portion) structure When a slit is provided around the GND terminal, a parasitic inductance is generated. It is effective to provide a bridge portion that electrically connects the two.

  The inductance of the bridge portion at this time is calculated. Assuming that the bridge portion is formed of a copper foil having a thickness of 35 μm, and assuming that the width is 50 μm and the length is 200 μm, which is the same as the slit width, the inductance per bridge portion is 0.156 nH. It is. If this inductance is unacceptable for the attenuation of the filter, it is possible to reduce the inductance by increasing the width of the bridge portion or increasing the number while considering the thermal resistance difference. As described above, in the present invention, it is possible to adjust the parasitic inductance of the device by adjusting the dimensions or the number of the bridge portions.

  As described above, according to the structure of the present invention in which the slit is formed around the GND terminal and the bridging portion is provided, the GND of the filter component can be made common at the position closest to the GND surface of the mounting substrate, and It is possible to configure a device that takes into account the thermal resistance difference between the signal and GND terminals.

It is side surface sectional drawing which shows the duplexer which concerns on one Embodiment of this invention. It is a bottom view which shows the duplexer (state which removed the soldering resist) which concerns on the said embodiment. It is a bottom view which shows the duplexer (state which has arrange | positioned the soldering resist) which concerns on the said embodiment. It is a figure which expands and shows the bottom face terminal part (a slit and a bridge part) of the duplexer which concerns on the said embodiment. It is a schematic diagram which shows the formation part of a signal terminal. It is a table | surface which shows the relationship between the slit width at the time of using a resin material as a base substrate material, and a thermal resistance value. It is a table | surface which shows the relationship between the slit width at the time of using LTCC as a base substrate material, and a thermal resistance value. It is a table | surface which shows the relationship between the slit width at the time of using HTCC as a base substrate material, and a thermal resistance value. It is a diagram which shows the relationship between the slit width and the thermal resistance difference in each case where a resin material, LTCC and HTCC are used as the base substrate material. It is a schematic diagram which shows the formation part of an external connection terminal (a signal terminal, a GND terminal), (a) is a signal terminal, (b) is a GND terminal (when a slit is not formed), (c) is a GND terminal (a slit is formed). (When formed), (d) shows a GND terminal (when a slit and a bridging portion are formed), respectively. It is a table | surface which shows the calculation result of the thermal resistance in each terminal structure of (a)-(d) of the said FIG. It is a table | surface which shows the thermal resistance difference between a signal terminal -GND terminal when the slit of width 10-500 micrometers is provided around the GND terminal. It is a diagram which shows the relationship between the slit width formed in the circumference | surroundings of a GND terminal, and the thermal resistance difference between a signal terminal -GND terminal. It is a bottom view which shows an example of the conventional duplexer. It is a bottom view which shows another example of the conventional duplexer. It is side surface sectional drawing which shows an example of the conventional duplexer. FIG. 17 is a schematic diagram showing parasitic inductance in the duplexer of FIG. 16 (when the mounting substrate has no reference potential deviation). FIG. 17 is a schematic diagram showing parasitic inductance in the duplexer of FIG. 16 (when the mounting substrate has a reference potential deviation). It is side surface sectional drawing which shows another example of the conventional duplexer. FIG. 20 is a schematic diagram showing parasitic inductance in the duplexer of FIG. 19. It is side surface sectional drawing which shows another example of the conventional duplexer. It is a schematic diagram which shows the parasitic inductance in the duplexer of the said FIG.

Explanation of symbols

1 Signal terminal (transmission terminal)
2 Signal terminal (Reception terminal)
3 Signal terminal (antenna terminal)
4 GND terminal 21 Duplexer 22 Base substrate 23 Cover 24 Transmission filter element 25 Reception filter element 35 Common GND part 36 Slit 37 Bridge part 40 Solder resist (solder mask)

Claims (5)

A signal terminal for external connection, a reference potential terminal for external connection, and a common reference potential portion electrically connected to the reference potential terminal for external connection, all formed of a conductor on one surface of the package A filter with
A filter comprising a slit for partially separating the common reference potential portion and the reference potential terminal between the common reference potential portion and the reference potential terminal.   The filter according to claim 1, wherein the filter is a surface acoustic wave filter. A signal terminal for external connection, a reference potential terminal for external connection, and a common reference potential portion electrically connected to the reference potential terminal for external connection, all formed of a conductor on one surface of the package A duplexer with
A duplexer characterized in that a slit portion for partially separating the common reference potential portion and the reference potential terminal is provided between the common reference potential portion and the reference potential terminal.   The duplexer according to claim 3, wherein the duplexer is a surface acoustic wave duplexer. The common reference potential portion is formed over substantially the entire one surface of the package excluding the signal terminal forming portion and is electrically connected to the reference potential terminal.
Between the common reference potential portion and the reference potential terminal, the slit portion and a bridging portion made of a conductor electrically connected to the common reference potential portion and the reference potential terminal are formed,
The filter or duplexer according to any one of claims 1 to 4, wherein the reference potential terminal is defined by a solder resist disposed on one surface of the package.

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