JP2007036452A - High frequency module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized high frequency module with excellent characteristics that can enhance isolation characteristics between terminals of a semiconductor integrated circuit element without revising the structure of the semiconductor integrated circuit element. <P>SOLUTION: The high frequency module is arranged between an antenna terminal and a transmission system circuit or a reception system circuit of a plurality of communication systems adopting different frequency bands or different communication methods and is characterized in to include: the semiconductor integrated circuit element 2 wherein a high frequency switch switchable to the communication systems and a control circuit for controlling switching of the high frequency switch are integrated; a filter element 3 connected to a transmission terminal of the semiconductor integrated circuit element 2 and for attenuating harmonic signals in a transmission signal; and a lead frame 1 mounted with the semiconductor integrated circuit element 2 and the filter element 3, and the filter element 3 is mounted on the lead frame and the semiconductor integrated circuit element 2 is mounted on the filter element 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high frequency module disposed between an antenna terminal and a transmission system circuit or a reception system circuit of a plurality of communication systems having different frequency bands or communication methods, and is particularly preferably used for a mobile radio terminal supporting multiband. This relates to a high-frequency module.

  In recent years, a mobile phone adopting a multiband system in which two or more communication systems are mounted in one mobile phone has been proposed. A multiband mobile phone is expected to be a highly convenient mobile phone because it can select and transmit / receive a communication system suitable for regional characteristics and purpose of use. For example, as a plurality of communication systems having different communication bands, there is a dual-band mobile phone equipped with two systems, a GSM (Global System for Mobile Communications) system and a DCS (Digital Cellular System) system.

FIG. 9 is a block diagram of a high frequency transmission module (T _X M) 100 of a general GSM / DCS dual-band mobile phone.

The radio frequency transmission modules 100, transmission circuit _{T X} of the transmitting and receiving system circuit GSM, a receiving circuit _{R X,} transmitting circuit _{T X} of the transmitting and receiving system circuit DCS, together and a reception system circuit _{R X,} different frequency bands RF module two transceiver circuits GSM / DCS, respectively demultiplexed into reception system circuit GSM and DCS, performs switching of the reception system circuit GSM, respectively transmitting circuit _{T X} in DCS and the receiving system circuit _{R X} (ASM) 200 is provided.

GSM transmitting circuit _{T X} supplies a transmission signal amplified by the power amplifier circuit (AMP) 402, through a matching circuit (MAT) 401 made of a low-pass filter, the high frequency module 200. The high-frequency signal supplied to the high-frequency module 200 is transmitted as a high-frequency signal from the antenna (ANT) 300 via the semiconductor integrated circuit element and the branching circuit, as will be described later. Above operation is the same for DCS transmitting circuit _{T X.}

On the other hand, GSM receiving circuit _{R X} is a high-frequency signal received by the antenna 300, is taken out via the high-frequency module 200, removes an unnecessary signal of the reception band near at band pass filter (BPF) 501. Signal passed through the band pass filter 501 is amplified by R _X side low noise amplifier (low noise AMP) 502, is input to the signal processing circuits. The above operation is the same for DCS receiving circuit _{R X.}

  By the way, based on future market trends, it is expected that high-quality voice and image data transmission using a mobile phone terminal will be performed, and in order to cope with these, CDMA, which is a code division multiple access system, is used. Construction of a communication system capable of large-capacity data transmission such as (Code Division Multiple Access) and a next-generation communication system UMTS (Universal Mobile Telecommunications System) characterized by high-speed data transmission rate and multiplexing of communication channels is progressing.

  Thus, in order to cope with a plurality of communication systems, it is necessary to support more bands with one module. For example, there is an increasing demand for multiband systems such as GSM850 / GSM900 / DCS / PCS (Personal Communication Services) / UMTS.

  In this way, when multi-bands / modes are advanced and it becomes necessary to support more bands / modes with one high-frequency module, the surface layer space of the high-frequency module mounting board proportional to the number of bands / modes is required, resulting in an increase in size. However, the high-frequency module 200 is also required to be downsized.

  On the other hand, recently, as a means for performing transmission / reception switching inside the high-frequency module 200 with the aim of downsizing and low loss, a high-frequency switch that can be switched corresponding to a plurality of communication systems and control for switching the high-frequency switch. A configuration using a semiconductor integrated circuit element in which circuits are integrated, for example, a semiconductor integrated circuit element made of GaAs (gallium arsenide) has been studied.

When such a semiconductor integrated circuit element is used for a multiband system such as GSM850 / GSM900 / DCS / PCS / UMTS, which is a multiband / mode, normally, as shown in FIG. Is connected to a demultiplexing circuit (DIPX) 600 for demultiplexing the transmission / reception system circuits on the high side and the high band side, and a low band side low pass filter (LPF) of the demultiplexing circuit 600, for example, a transmission system circuit T in transmission / reception of GSM850 / GSM900 a semiconductor integrated circuit device 701 to switch between _X and the receiving system circuit _{R X,} is connected to the High band high-pass filter of the diplexer circuit 600 (HPF), for example, DCS / PCS / transmitting circuit in the transmitting and receiving UMTS _{T X} and a semiconductor integrated circuit device 702 for switching the reception system circuit _{R X} and UMTS and It is necessary to prepare a high frequency module 204. At this time, the semiconductor integrated circuit element 702 needs to satisfy good linearity and power durability in order to support the GSM method and the CDMA or UMTS method which are two different modes.

Also, when not using a demultiplexing circuit, as shown in FIG. 11, is connected to the antenna terminal, for example GSM850 / GSM900 / DCS / PCS / reception system circuit and the transmission circuit _{T X} each transmission and reception of UMTS _{R X} It is necessary to prepare the high frequency module 205 including the semiconductor integrated circuit element 703 to be switched to.

As a high-frequency module as described above, a semiconductor integrated circuit element 42 and a filter element (LPF) 43 are mounted side by side on a lead frame 41 as shown in FIG. A structure in which the pads 421 and a plurality of lead terminals 411 formed on the surface of the lead frame 41 are connected by bonding wires 44 and the surface is sealed with resin has been adopted (see Patent Document 1).
JP 2004-304581 A

  However, in the structure shown in FIG. 12, the size of the high-frequency module is limited by the size of the semiconductor integrated circuit element 2 and the filter element 3, and cannot be further reduced. For example, in correspondence with GSM850 / GSM900 / DCS / PCS / UMTS, the size of the high-frequency module is about 4.5 × 3.2 mm.

  In addition, when the multi-band / mode is supported, the number of switching transistors configured in the semiconductor integrated circuit element is increased, and further, in order to realize low loss, power durability, and low distortion characteristics, The transistor size increases.

  As described above, it is difficult to reduce the size of the conventional high-frequency module due to its structure, and there is a problem in that the size of the conventional high-frequency module increases as a whole due to the multiband / mode compatibility.

  Further, in the case of supporting the multiband / mode, there is a problem that the number of terminals configured in the semiconductor integrated circuit element increases and the isolation characteristic between the terminals deteriorates. In order to solve this problem, FIG. As shown in FIG. 2, when the path from the ANT terminal to the a terminal via the transistor Tr1 and the path from the ANT terminal to the b terminal via the transistor Tr3 are provided to be branched, A configuration is used in which a shunt transistor Tr2 is formed in this path while being connected between the transistors Tr1. This is because when the transistor Tr1 in the path from the ANT terminal to the a terminal is off and the transistor Tr3 in the path from the ANT terminal to the b terminal is in the on state, the transistor Tr2 is on and the terminal b to the terminal a The isolation characteristics are improved. When the transistor Tr1 is on and the transistor Tr3 is off, the transistor Tr2 is off, improving the isolation characteristics from the terminal a to the terminal b.

  However, the isolation characteristics are affected by the potential of the ground electrode. In general, a ground electrode is formed on the lower surface of the semiconductor integrated circuit element. In the conventional configuration in which the semiconductor integrated circuit element is directly mounted on the lead frame, the potential of the ground electrode cannot be corrected. In order to improve the transmission characteristics, it is necessary to change the structure of the semiconductor integrated circuit element. If it does so, there will be a problem that it takes time and cost to newly manufacture a semiconductor integrated circuit element.

  An object of the present invention is to provide a small high-frequency module that can improve isolation characteristics between terminals of a semiconductor integrated circuit element without changing the structure of the semiconductor integrated circuit element, and has good characteristics.

  The high frequency module of the present invention is a high frequency module disposed between a transmission system circuit or a reception system circuit of a plurality of communication systems having different frequency bands or communication methods and an antenna terminal, and corresponds to the plurality of communication systems. A semiconductor integrated circuit element in which a switchable high-frequency switch and a control circuit for controlling the switching of the high-frequency switch are integrated, and is connected to a transmission terminal of the semiconductor integrated circuit element to attenuate a harmonic signal of the transmission signal A filter element, a semiconductor integrated circuit element, and a lead frame on which the filter element is mounted. The filter element is mounted on the lead frame, and the semiconductor integrated circuit element is mounted on the filter element. It is characterized by being mounted.

  Thus, by mounting the semiconductor integrated circuit element on the filter element, the size of the high frequency module can be reduced. Furthermore, by optimizing the potential of the ground electrode on the surface of the filter element, the isolation characteristic between the terminals of the high-frequency semiconductor integrated circuit element can be improved.

  Here, in the high-frequency module of the present invention, a circuit element for attenuating a transient high voltage surge applied to the antenna terminal is arranged in a path from the antenna terminal to the semiconductor integrated circuit element. As described above, it is preferable that the filter element is juxtaposed with the filter element on the lead frame.

  Thus, by providing the filter element for high voltage surge attenuation, it is possible to prevent the high frequency semiconductor integrated circuit element from being damaged by the high voltage surge.

  ADVANTAGE OF THE INVENTION According to this invention, the isolation characteristic between the terminals of a semiconductor integrated circuit element can be improved, without changing the structure of a semiconductor integrated circuit element, and the small high frequency module which has a favorable characteristic is obtained.

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

  The high-frequency module of the present invention is premised on the use of a high-frequency switch having one terminal connected to the antenna terminal side and the other terminal having M (M is an integer of 2 or more). Hereinafter, examples corresponding to five communication systems will be described.

  FIG. 1 is a block diagram for explaining an example of a high-frequency module of a multi-band mobile phone terminal according to the present invention, and a region surrounded by a dotted line in the figure indicates the high-frequency module.

  A high-frequency module 201 shown in FIG. 1 is connected to one common antenna terminal ANT, and includes GSM850 (850 MHz band), GSM900 (900 MHz band), DCS (1800 MHz band), PCS (1900 MHz band), and UMTS (2100 MHz band). This module switches between five communication systems.

The RF module _201, a high frequency switching _{GSM850 / 900-T X, GSM850} -R X, GSM900-R X, DCS / PCS-T X, DCS-R X, PCS-R X, the _{UMTS-T X} / _R X A semiconductor integrated circuit element 2 having a function as a switch is provided. The semiconductor integrated circuit element 2 includes a control circuit that controls the switching state of the switches.

Further, GSM850 / _{900-T X} and the semiconductor integrated circuit elements 2 and the low-pass filter LPF1 for attenuating harmonic components of the transmitted signal in the path of, the path of the DCS / _{PCS-T X} and the semiconductor integrated circuit device 2 And a low-pass filter LPF2 for attenuating the harmonic component of the transmission signal. These low-pass filters LPF1 and LPF2 are low-pass filters arranged for the purpose of removing harmonics generated from a transmission power amplifier (not shown).

Transmission system terminal GSM850 _/ 900-T X of the semiconductor integrated circuit device 2, the DCS / _{PCS-T X} power amplifier (not shown) is connected, the receiving system terminal _{GSM850-R X, GSM900-R} X, DCS- R _X, a low noise amplifier (not shown) in _{PCS-R X} are a duplexer (not shown) is connected to the _{UMTS-T X} / _R X.

  On the other hand, FIG. 2A is a schematic circuit of a semiconductor integrated circuit element including switching transistors Q1 to Q4 (generally indicated by Q), and FIG. 2B is a characteristic diagram of the switching transistor Q. It is. In FIG. 2B, the horizontal axis represents the gate-source voltage Vgs, and the vertical axis represents the drain current Id. The switching transistor Q is a so-called depletion type that can be turned off by making the gate-source voltage Vgs negative. The semiconductor integrated circuit element 21 is simplified by taking out only the minimum necessary part of the semiconductor integrated circuit element 2 shown in FIG.

The operation of the semiconductor integrated circuit element 21 having the above characteristics will be described.
When the path between the ANT terminal and the T _X 1 terminal is on, the control voltage V1 is set to High (2.8V) and the control voltages V2 to V4 are set to Low (0.2V), so that the transistor Q1 is in a conductive state, and the transistor Q2 ˜Q4 becomes non-conducting and the path is turned on. Similarly, when the path of the ANT terminal and the T _X 2 terminal, the path of the ANT terminal and the R _X 1 terminal, and the path of the ANT terminal and the R _X 2 terminal are turned on, the voltage for controlling the transistor of the path is also set to High. By setting the voltage for controlling the transistor to Low, the path can be turned on.

Next, the structure of the high frequency module of the present invention will be described.
FIG. 3 is a structural diagram of the high-frequency module 201 configured by the circuit of FIG. 1, and FIG. 4 is a plan view of the lead frame shown in FIG.

  As shown in FIG. 4, the lead frame 1 includes a lead frame body 12 made of a resin material, a ground electrode pad 11 formed at a substantially central portion of the surface of the lead frame body 12, and a plurality of leads formed at the peripheral edge. Consists of a terminal 10. A filter element (LPF) 3 is mounted in a region surrounded by a dotted line A.

  As shown in FIG. 3, the filter element 3 is mounted on the ground electrode pad 11 located substantially in the center of the lead frame 1, and both are electrically connected by a conductive binder such as a metal paste or a solder paste. Connection is made. On the lower surface of the filter element 3, land grid array terminals (LGA terminals) corresponding to the shapes of the lead terminals 10 and the ground electrode pads 11 of the lead frame 1 are formed. The LGA terminal includes a connection terminal with the semiconductor integrated circuit element 2, a connection terminal with a lead terminal for connection to an external component, and a ground electrode terminal.

As shown in FIG. 5, the filter element 3 is constituted by a dielectric multilayer substrate B in which a dielectric layer and a conductor layer are laminated. As shown in FIG. 1, the filter element 3 is connected to the semiconductor integrated circuit element 2 and the GSM850 / a low-pass filter LPF1 which is inserted between the _{900-T X} terminal, the low-pass filter LPF2 is the inner layer that is likewise inserted between the semiconductor integrated circuit device 2 and the DCS / _{PCS-T X} terminal.

  The dielectric multilayer substrate B is formed by laminating dielectric layers 51 to 57 having the same size and shape, and a conductor layer having a pattern constituting the low-pass filters LPF1 and LPF2 between the dielectric layers 51 to 57. 61 is formed. Such dielectric layers 51 to 57 are formed of, for example, ceramic for low-temperature firing, and the conductor layer 61 is formed of a low resistance conductor such as copper or silver.

Each dielectric layer 51 to 57 is appropriately formed with a via-hole conductor (not shown) necessary for configuring or connecting a circuit across a plurality of layers. Further, a ground electrode pattern 62 for mounting the semiconductor integrated circuit element 2 is formed on the upper surface of the filter element 3, and is connected to the ground electrode terminal on the lower surface by a plurality of via hole conductors (not shown). . These are formed by a well-known multilayer ceramic technology. For example, a conductive paste is applied to the surface of a ceramic green sheet to form conductor patterns constituting the above-described circuits, and then the green sheets are laminated. Then, it is formed by thermocompression bonding and firing under the required pressure and temperature.

Then, as shown in FIG. 3, the semiconductor integrated circuit element 2 is mounted on the ground electrode pattern 62. The semiconductor integrated circuit element 2 includes a semiconductor element such as p-HEMT mounted on a substrate mainly composed of a GaAs (gallium arsenide) compound, Si (silicon), or Al ₂ O ₃ (sapphire). A switching circuit pattern and a control circuit using semiconductor elements are formed.

  A ground electrode is formed on the lower surface of the semiconductor integrated circuit element 2 (not shown). The ground electrode and the ground electrode pattern 62 on the upper surface of the filter element 3 are made of conductive material in which an adhesive is mixed with Ag or AuSn. Electrical connection is made by a conductive adhesive or an organic resin non-conductive adhesive. An electrode pad 20 is formed on the upper surface of the semiconductor integrated circuit element 2, and the electrode pad 20 and the lead terminal 10 are electrically connected by a bonding wire 30. The lead terminal 10 is connected to an external component of the high frequency module.

  After being configured as described above, these surfaces are sealed with a sealing resin such as an epoxy resin to complete a high-frequency module.

  As described above, the structure in which the semiconductor integrated circuit element is mounted on the filter element has the following effects.

  The potential of the ground electrode pattern 62 formed on the upper surface of the filter element 3 can be changed by changing the number of via-hole conductors that connect the ground electrode pattern 62 and the ground electrode terminal on the lower surface. Since the potential of the ground electrode pattern 62 affects the isolation characteristics between the terminals of the semiconductor integrated circuit element 2, the potential of the ground electrode pattern 62 on the upper surface of the filter element 3 is optimized, whereby the semiconductor integrated circuit element 2. The isolation characteristic between the terminals can be optimized. That is, the potential can be adjusted by changing the structure of the filter element 3 which is advantageous in terms of cost without changing the structure of the semiconductor integrated circuit element 2.

FIG. 6 shows a circuit diagram of a second embodiment of the high-frequency module of the present invention.
In the high frequency module 202 shown in FIG. 6, in the path of the GSM850 / _{900-T X,} between the semiconductor integrated circuit device 2 and a low-pass filter LPF1, the phase adjustment line SL1 is inserted. Similarly, also in the DCS / PCS-TX path, the phase adjustment line SL2 is inserted between the semiconductor integrated circuit element 2 and the low-pass filter LPF2.

According to such insertion of the phase adjustment line, when a signal transmitted from a power amplifier circuit (not shown) is input to the _TX path of the high frequency module 202, it is generated due to nonlinearity of the semiconductor integrated circuit element 2. It is possible to suppress unnecessary harmonic components that would occur.

  When the phase adjustment lines SL1 and SL2 are formed of distributed constant lines, the phase adjustment lines SL1 and SL2 are inner layers of the filter element 3, but by adjusting the length of the wire connecting the semiconductor integrated circuit element 2 and the filter element 3 It may be formed.

Here, FIG. 7 shows a graph of changes in unnecessary harmonic components due to phase adjustment.
The graph of Figure 7, when _{GSM900-T X} mode shows an unnecessary harmonic component of double frequency (1800 MHz) and 3 times the frequency of 900MHz fundamental frequency (2700 MHz). The horizontal axis represents the phase of the impedance when the semiconductor integrated circuit element 2 is viewed from the phase adjustment line SL1 side. The vertical axis represents the difference between the electric energy of the unnecessary harmonic component and the electric energy of the fundamental frequency signal. The larger the numerical value, the smaller the unnecessary harmonic component and the better the characteristics.

  From the graph of FIG. 7, in the case of double frequency, by adjusting the impedance phase in the range of 80 ° to 180 ° and −120 ° to −180 °, the unnecessary harmonic component becomes 70 dBc or more, and good characteristics are obtained. Obtainable. In the case of triple frequency, by adjusting the impedance phase in the range of −120 ° to −180 °, the unnecessary harmonic component becomes 70 dBc or more, and good characteristics can be obtained.

  As described above, an unnecessary harmonic component generated from the semiconductor integrated circuit element 2 can be suppressed by optimizing the phase of the impedance viewed from the semiconductor integrated circuit element 2 toward the filter element 3 by the phase adjustment line.

FIG. 8 shows a structural diagram of a third embodiment of the high-frequency module of the present invention.
In the high-frequency module 203 shown in FIG. 8, the filter element 3 is mounted on the lead frame 1 so as to be electrically connected to the ground electrode pad 11 located at the center of the lead frame 1, and the upper surface of the filter element 3 is grounded. The semiconductor integrated circuit element 2 is mounted on the electrode, the electrode pad 20 on the upper surface of the semiconductor integrated circuit element 2 and the lead terminal 10 are connected by the bonding wire 30, and the semiconductor integrated circuit is further connected from the antenna terminal of the high frequency module 203. A high voltage surge attenuating circuit element 70 is juxtaposed with the filter element 3 on the lead frame 1 so as to be arranged in a path leading to the circuit element 2.

  One end of the high-voltage surge attenuation circuit element 70 is connected to the lead terminal 12 connected to the antenna terminal of the high-frequency module 203, and the other end is connected to the ground electrode pad 11. For example, the high-voltage surge attenuation circuit element 70 includes an inductor element or a parallel circuit of an inductor element and a varistor element.

  In general, a semiconductor integrated circuit element that does not take high voltage surge countermeasures is destroyed when a voltage of about 0.1 kV is applied to an antenna terminal. In the standard regarding the high voltage surge of the electronic component, it is usually necessary that the high voltage surge of 4 kV is not broken even in the contact mode. Thus, by providing the circuit element for high voltage surge attenuation, The destruction of the high-frequency semiconductor integrated circuit element due to the high voltage surge can be prevented.

Having described the embodiments of the present invention, the present invention is not limited to these embodiments, for example, it is connected to the GSM850 / _{900-T X} terminal and the DCS / _{PCS-T X} terminal power An amplifier circuit, an automatic power control circuit, a band pass filter such as a SAW filter, and the like may be integrated and mounted inside the high frequency module shown in the present embodiment.

Further, a duplexer connected to the UMTS terminal, a power amplifier circuit, an automatic power control circuit, a band pass filter such as a SAW filter, and the like may be integrated and mounted inside the high frequency module shown in the present embodiment. Furthermore, _{GSM850-R X} terminal, _{GSM900-R X} terminal, _{DCS-R X} terminal, band pass filter such as a SAW filter connected to the _{PCS-R X} terminals, integrated within a high-frequency module shown in this embodiment May be installed.

It is a circuit block diagram which shows an example of the high frequency module of this invention. (A) is a schematic circuit diagram of the semiconductor integrated circuit device of the present invention, and (b) is a graph showing the basic operation of the transistors constituting the semiconductor integrated circuit device. It is a structural diagram showing an example of a high frequency module of the present invention. FIG. 4 is a structural diagram of the lead frame 1 shown in FIG. 3. FIG. 4 is a partially cutaway perspective view showing the internal structure of the filter element 3 shown in FIG. 3. It is a circuit diagram which shows 2nd Embodiment of the high frequency module of this invention. It is a graph which shows the change of the unnecessary harmonic component by the change of the phase of the impedance which looked at the filter element side from the semiconductor integrated circuit element based on 2nd Embodiment of the high frequency module of this invention. It is a block diagram which shows 3rd Embodiment of the high frequency module of this invention. It is a block diagram showing a radio frequency transmission modules _(T X M) 100 of the portable telephone terminal of the dual band system of the GSM / DCS system. It is a block diagram which shows the conventional high frequency module. It is a block diagram which shows the conventional high frequency module. It is a structural diagram showing a conventional high-frequency module. It is a typical circuit diagram of the conventional semiconductor integrated circuit element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lead frame 10 ... Lead terminal 11 ... Ground electrode pad 12 ... Lead frame main body 2, 21 ... Semiconductor integrated circuit element 20 ... Electrode pad 3 ... ... Filter elements 201, 202, 203 ... High frequency module 30 ... Bonding wires LPF1, LPF2 ... Low-pass filter SL1, SL2 ... Phase adjustment lines 51, 52, 53, 54, 55, 56, 57 .. Dielectric layer 61... Conductor pattern 62... Ground electrode pattern 70... High voltage surge attenuation circuit element A. Multilayer board

Claims (2)

A high frequency module disposed between a transmission system circuit or a reception system circuit of a plurality of communication systems having different frequency bands or communication methods, and an antenna terminal,
A semiconductor integrated circuit element in which a switchable high-frequency switch corresponding to the plurality of communication systems and a control circuit for controlling switching of the high-frequency switch are integrated;
A filter element that is connected to a transmission terminal of the semiconductor integrated circuit element and attenuates a harmonic signal of a transmission signal;
A lead frame on which the semiconductor integrated circuit element and the filter element are mounted;
The high-frequency module, wherein the filter element is mounted on the lead frame, and further the semiconductor integrated circuit element is mounted on the filter element. The filter on the lead frame so that a circuit element for attenuating a transient high voltage surge applied to the antenna terminal is disposed in a path from the antenna terminal to the semiconductor integrated circuit element. The high-frequency module according to claim 1, wherein the high-frequency module is arranged in parallel with the element.

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