Integrated channel isolation radio frequency transformer module

Abstract

The utility model discloses an integrated channel isolation radio-frequency transformer module, which belongs to the technical field of radio-frequency transformers and specifically structurally comprises a PCB (printed circuit board), radio-frequency transformer modules and a metal shielding shell, the radio-frequency transformer modules with a plurality of channels are arranged side by side in the length direction of the PCB, and the metal shielding shell is provided with an accommodating cavity with an opening at the lower end. The PCB is provided with a containing cavity, the containing cavity is provided with a plurality of metal partition plates at equal intervals to form a plurality of isolation cavities, the metal partition plates are arranged in the length direction of the PCB, each isolation cavity contains one radio frequency transformer module, and the PCB is provided with an input bonding pad and an output bonding pad corresponding to each channel radio frequency transformer module. According to the utility model, the isolation degree of two adjacent channels is improved, crosstalk between the two channels is avoided, and miniaturization is facilitated.

Description

Technical Field

[0001] This utility model relates to an integrated channel isolation radio frequency transformer module, belonging to the field of multi-channel radio frequency transformer technology. Background Technology

[0002] A radio frequency transformer is a transformer specifically designed to process high-frequency signals. Its core function is to realize key functions such as impedance matching, signal coupling, voltage transformation, isolation, and power transmission in high-frequency circuits.

[0003] Digital and analog circuits in radio frequency (RF) circuits require a large number of ADCs and DACs. To meet the needs of integration and miniaturization, ADC and DAC chips are generally multi-channel (5, 8, 10, 16, etc.). Each channel of the ADC front end and DAC back end requires a large number of RF transformers. There are isolation requirements between each channel. Since the magnetic core of the RF transformer has a magnetic field, crosstalk will be generated between transformers. The distance between two transformers will affect the isolation between channels. If the RF transformers of two channels are placed too close, the isolation will be reduced, resulting in crosstalk between the two channels. Moreover, if an isolation enclosure is added, it will result in a large space occupation and affect the equipment. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an integrated channel isolation radio frequency transformer module, which improves the isolation between two adjacent channels, avoids crosstalk between the two channels, and facilitates miniaturization.

[0005] The technical solution adopted by this utility model is as follows: an integrated channel isolation RF transformer module, including a PCB board, an RF transformer module and a metal shielding shell. Multiple RF transformer modules with multiple channels are arranged side by side along the length of the PCB board. The metal shielding shell is provided with a receiving cavity with an opening at the lower end. The receiving cavity is provided with multiple metal partitions with the same spacing to form multiple isolation cavities. The multiple metal partitions are arranged along the length of the PCB board. Each isolation cavity accommodates one RF transformer module. The PCB board is provided with input pads and output pads corresponding to each channel RF transformer module.

[0006] Furthermore, each of the above-mentioned RF transformer modules includes a ferrite core, enameled wire, and an isolation capacitor. The enameled wire is wound around the ferrite core, and the free end of the enameled wire is electrically connected to the enameled wire pad using a high-temperature tin layer. The ferrite core is bonded to the PCB board using an epoxy resin layer, and the isolation capacitor is electrically connected to the capacitor pad using a high-temperature tin layer.

[0007] Furthermore, the metal shielding shell has two positioning plugs at one end of its opening, and the PCB board has two positioning holes corresponding to the positioning plugs. The two positioning plugs are inserted into the two positioning holes.

[0008] Furthermore, the PCB board is provided with a metal isolation frame around the bottom of each isolation cavity, and the metal isolation frame is fixedly connected to the isolation cavity by high-temperature solder.

[0009] The beneficial effects of this utility model are as follows: Compared with the prior art, this utility model integrates a multi-channel RF transformer module onto a PCB board and uses a metal shielded shell with partitions to form an independent isolation cavity to physically isolate each RF transformer module, improve the isolation between channels, avoid crosstalk between channels, and allow adjacent RF transformer modules to be placed closer together while avoiding crosstalk, making the multi-channel RF transformer module more compact and smaller in structure, which is conducive to miniaturization and can reduce the size by more than half. Attached Figure Description

[0010] Figure 1 This is a three-dimensional structural diagram of an integrated channel isolation RF transformer module;

[0011] Figure 2 This is a front view schematic diagram of the integrated channel isolation RF transformer module;

[0012] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the middle AA section;

[0013] Figure 4 This is a top view of the integrated channel isolation RF transformer module (with the metal shielding shell removed).

[0014] Figure 5 This is a three-dimensional structural diagram of the metal shielding shell from the bottom view;

[0015] Figure 6 This is the pin layout diagram of the integrated channel isolation RF transformer module;

[0016] Figure 7 This is a functional schematic diagram of an integrated channel isolation radio frequency transformer module;

[0017] Figure 8 This is the circuit schematic of an integrated channel isolation RF transformer module.

[0018] Figure 6 Pin definitions: 2, 5, 8, 11, 14 - Single-ended input; First channel: 30: Differential N; 29: Differential P; Second channel: 27: Differential N; 26: Differential P;

[0019] Third channel: 24: Differential N; 23: Differential P; Fourth channel: 21: Differential N; 20: Differential P;

[0020] Fifth channel: 18: Differential N; 17: Differential P;

[0021] Other pins: Ground. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1: As Figure 1-8 As shown, an integrated channel isolation RF transformer module includes a high-frequency PCB board 1, an RF transformer module 2, and a metal shielding shell 3. Multiple RF transformer modules 2 with multiple channels are arranged side by side along the length of the PCB board 1. The metal shielding shell 3 has a receiving cavity with an opening at the lower end. The receiving cavity is provided with multiple metal partitions 4 with the same spacing to form multiple isolation cavities 5. The multiple metal partitions 4 are arranged along the length of the PCB board 1. Each isolation cavity 5 accommodates one RF transformer module 2. The PCB board 1 is provided with input pads 6 and output pads 7 corresponding to each channel RF transformer module 2.

[0024] By integrating a single-channel RF transformer into a single module, a multi-channel RF transformer module can be created. 2-channel, 3-channel, 4-channel...N-channel RF transformer modules are available. Depending on the application requirements, capacitors can be used to block DC signals from the output signal, achieving the goal of multi-channel integration and miniaturization of RF transformers.

[0025] Specifically, each of the above-mentioned RF transformer modules 2 includes a ferrite core 201, an enameled wire 202, and an isolation capacitor 203. The enameled wire 202 is wound on the ferrite core 201, and the free end of the enameled wire 202 is electrically connected to the enameled wire pad 204 by a high-temperature tin layer. The ferrite core 201 is bonded to the PCB board 1 by an epoxy resin layer, and the isolation capacitor 203 is electrically connected to the capacitor pad 205 by a high-temperature tin layer.

[0026] To enable rapid positioning of the metal shielding shell during installation, two positioning insertion parts 301 are provided at one end of the opening of the metal shielding shell 3. Two positioning holes 101 corresponding to the positioning insertion parts 301 are provided on the PCB board 1. The two positioning insertion parts 301 are inserted into the two positioning holes 101. Through the positioning insertion parts and positioning holes, the metal shielding shell can be quickly positioned on the PCB board, which is conducive to the reflow welding and sealing of the metal isolation frame and the isolation cavity of the metal shielding shell.

[0027] Specifically, the PCB board 1 is provided with a metal isolation frame 8 around the bottom of each isolation cavity 5. The metal isolation frame 8 and the isolation cavity 5 are fixedly connected by high temperature tin. The RF transformer is multi-channel integrated, and a metal isolation frame is designed for each channel on the PCB. The frame of the metal shielding shell corresponds one-to-one with the isolation frame of the PCB board and is encapsulated with tin to achieve complete physical isolation between each channel.

[0028] Using SMT (Surface Mount Technology) automatic placement technology, isolation capacitors are mounted onto the high-frequency PCB board using high-temperature solder paste. The PCB is designed with pads for connecting the transformer input and output, as well as pads for the isolation capacitors. Ferrite core 2 is bonded to the high-frequency PCB board with epoxy resin and cured at high temperature. Enamelled wire for the transformer input and output windings is then wound onto the ferrite core, and the ends of the transformer input and output windings are soldered to the enamelled wire pads on the PCB board using an electronic spot welder. High-temperature solder is used to solder the joints. A metal shielding shell and high-temperature solder are used to shield and seal the channels between the transformer modules.

[0029] The main function of the integrated channel isolation RF transformer module is that each channel can independently convert between single-ended and differential signals. It is mainly used in the front end of multi-channel ADCs and the back end of multi-channel DACs. The operating frequency is between 0.001MHz and 9000MHz, which belongs to the field of microwave technology.

[0030] Integrated channel isolation RF transformer modules are widely used in various RF circuits, including ADC front-ends and DAC back-ends, as well as in scenarios requiring conversion between single-ended and differential signals. They can achieve the following:

[0031] 1) The channel can independently convert between single-ended and differential signals;

[0032] 2. It features low insertion loss (insertion loss less than 3dB) and physical isolation between channels;

[0033] 3. Lightweight, compact, and high-temperature resistant (using high-temperature resistant materials: 180-grade enameled wire, core Curie temperature greater than 130℃, high-temperature solder paste, Rogers high-temperature PCB board, epoxy resin with a temperature resistance of 180℃).

[0034] Example 2: A method for fabricating an integrated channel isolation radio frequency transformer module, the method comprising the following steps:

[0035] 1) Isolation capacitor patch: Using a stencil that matches the PCB board, high-temperature solder paste is printed onto the enameled wire pads and capacitor pads on the PCB board using an automatic printing method. The isolation capacitor is then patched onto the capacitor pads using an automatic patching device, and then reflow soldering is used.

[0036] 2) Core bonding: using a shear force greater than 20 N / mm 2 The epoxy resin is used to bond the ferrite core of each channel's RF transformer module to the corresponding position of each channel's RF transformer module on the PCB board; and it is cured according to the epoxy resin curing temperature, which is 125-130℃.

[0037] 3) Wire threading: Wind the enameled wire of the primary and secondary windings of each channel's RF transformer module (the free ends of the primary winding are the two free ends of the enameled wire away from the isolation capacitor, and the free ends of the secondary winding are the two free ends of the enameled wire close to the isolation capacitor) onto the center column or both sides of the double-hole ferrite core according to the schematic diagram and the specified number of turns.

[0038] 4) Spot welding: Use a pulse electronic spot welding machine to weld the free ends of the enameled wires of the primary and secondary windings to the corresponding pads; the parameters of the spot welding machine are as follows: maximum output current is greater than or equal to 1000A, output waveform is adjustable (pulse, square wave); output pulse amplitude: 0.30-2.99V, output pulse time: 1-39.9ms, welding force 10-70 OZ, the pulse output of the spot welding machine includes paint removal pulse and welding pulse;

[0039] 5) Soldering and sealing of metal shielding shell: Use an automatic or semi-automatic dispensing machine to apply high-temperature solder paste to the enameled wire pads and capacitor pads for spot welding, as well as the metal isolation frame of the PCB board. Assemble the metal shielding shell onto the PCB board. Then use a reflow soldering machine to reflow the solder, where the high-temperature solder paste has a melting point of 240-245℃.

[0040] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. An integrated channel isolation radio frequency transformer module, characterized in that, The PCB board (1), the radio frequency transformer module (2) and the metal shielding shell (3) are provided. The PCB board (1) has multiple radio frequency transformer modules (2) arranged side by side along its length. The metal shielding shell (3) has a receiving cavity with an opening at the bottom. The receiving cavity is provided with multiple metal partitions (4) with the same spacing to form multiple isolation cavities (5). The multiple metal partitions (4) are arranged along the length of the PCB board (1). Each isolation cavity (5) accommodates one radio frequency transformer module (2). The PCB board (1) is provided with input pads (6) and output pads (7) corresponding to each channel radio frequency transformer module (2).

2. The integrated channel isolation radio frequency transformer module according to claim 1, characterized in that, Each RF transformer module (2) includes a ferrite core (201), an enameled wire (202), and an isolation capacitor (203). The enameled wire (202) is wound on the ferrite core (201). The free end of the enameled wire (202) is electrically connected to the enameled wire pad (204) by a high-temperature tin layer. The ferrite core (201) is bonded to the PCB board (1) by an epoxy resin layer. The isolation capacitor (203) is electrically connected to the capacitor pad (205) by a high-temperature tin layer.

3. The integrated channel isolation radio frequency transformer module according to claim 1, characterized in that, The metal shielding shell (3) has two positioning plugs (301) at one end of the opening. The PCB board (1) has two positioning holes (101) corresponding to the positioning plugs (301). The two positioning plugs (301) are inserted into the two positioning holes (101).

4. The integrated channel isolation radio frequency transformer module according to claim 1, characterized in that, The PCB board (1) is provided with a metal isolation frame (8) around the bottom of each isolation cavity (5), and the metal isolation frame (8) and the isolation cavity (5) are fixedly connected by high temperature tin.

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