Phase-locked crystal oscillator with ultra-small volume

Abstract

The utility model discloses a phase-locked crystal oscillator with an ultra-small volume, which comprises a PCB (printed circuit board) and a component assembly mounted on the PCB, a metal shell is packaged on the PCB, the edge of the PCB is provided with a positioning part, an opening of the metal shell is provided with a positioning piece, and the metal shell is connected and positioned with the positioning part through the positioning piece. The opening edge of the metal shell is close to the edge of the PCB, and the component assembly is accommodated in the metal shell; the overall size of the PCB and the metal shell is 14 mm * 9 mm * 2.1 mm. By adopting the arrangement, the size of the phase-locked crystal oscillator can be further miniaturized, so that the phase-locked crystal oscillator is convenient and rapid to install, easy to produce in batches, low in cost and convenient to maintain and process.

Description

Technical Field

[0001] The utility model belongs to the technical field of crystal oscillator packaging structure, and in particular relates to an ultra-small phase-locked crystal oscillator. Background Art

[0002] The structure of a phase-locked crystal oscillator consists mainly of the oscillator itself and analog or digital auxiliary control circuits used to improve the stability of the oscillator. This composite structure corrects and "locks" the desired frequency characteristics through a feedback network, thereby achieving adjustment of the resonant characteristics or oscillator excitation.

[0003] The existing phase-locked crystal oscillator mostly adopts a miniaturized sampling phase-locked dielectric oscillator or a PT14C surface-mount phase-locked constant temperature crystal oscillator; among them, the miniaturized sampling phase-locked dielectric oscillator usually adopts a hybrid integrated circuit process, the circuit board adopts a ceramic substrate, most of the components are bare chips, and are sealed by laser welding, and its volume is usually 40mm*40mm*12.8mm; while the PT14C surface-mount phase-locked constant temperature crystal oscillator usually adopts a surface-mount package, and the size is usually 20.32mm*12.7mm*6.0mm. It can be seen from this that the volume of the existing phase-locked crystal oscillator still has the improvement breakthrough that can be miniaturized, so there is still room for improvement. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide an ultra-small phase-locked crystal oscillator, which can further miniaturize the volume of the phase-locked crystal oscillator to save production costs.

[0005] The purpose of the utility model is achieved through the following technical solutions:

[0006] An ultra-small phase-locked crystal oscillator comprises a PCB board and a component assembly mounted on the PCB board, wherein the PCB board is encapsulated with a metal shell, a positioning portion is provided at the edge of the PCB board, a positioning piece is provided at the opening of the metal shell, the metal shell is connected and positioned with the positioning portion through the positioning piece, the opening edge of the metal shell is close to the edge of the PCB board, and the component assembly is accommodated in the metal shell; the overall size of the PCB board and the metal shell is 14mm*9mm*2.1mm.

[0007] Furthermore, the positioning portion includes a positioning notch opened on the edge of the PCB board, and the positioning member includes a positioning block arranged on the opening edge of the metal shell, the positioning block is adapted to the positioning notch, and the positioning block is welded and fixed in the positioning notch.

[0008] Furthermore, the positioning portion includes a magnetic patch embedded in the edge of the PCB board, and the positioning piece includes a metal protrusion arranged on the opening edge of the metal shell, the metal protrusion is magnetically fixed to the magnetic patch, and the metal protrusion is welded and fixed to the magnetic patch.

[0009] Furthermore, the number of the positioning parts is two, and the two positioning parts are respectively located at two vertex corners of the relative edges of the PCB board; the number of the positioning pieces is two, and the two positioning pieces are respectively located at two vertex corners of the relative edges in the opening of the metal shell; the two positioning pieces of the metal shell respectively correspond to the two positioning parts of the PCB board.

[0010] Furthermore, the component assembly includes a resistor patch, a capacitor patch, a phase-locked loop, a transistor, a crystal, an LDO regulator and a gate circuit mounted on the PCB board.

[0011] Furthermore, the crystal is a 3525 chip crystal.

[0012] Furthermore, the resistor patch and the capacitor patch are both packaged in 0201.

[0013] The utility model has the following beneficial effects:

[0014] The ultra-small phase-locked crystal oscillator of the utility model has a positioning portion arranged on the edge of a PCB board, and the middle position thereof is used for mounting component assemblies, so that the mounting positions of the component assemblies are more integrated, thereby achieving the effect of reducing the mounting space; at the same time, a positioning piece corresponding to the positioning portion is arranged through the opening edge of a metal shell, and the positioning piece of the metal shell is connected and positioned with the positioning portion of the PCB board so that the component assembly is accommodated in the metal shell, thereby reducing the overall structural integration volume of the phase-locked crystal oscillator of the PCB board and the metal shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic cross-sectional view of the overall structure of the utility model.

[0016] Figure 2 It is a three-view drawing of the metal shell of the utility model.

[0017] Figure 3 It is a structural diagram of the PCB board of the utility model.

[0018] Figure 4 It is a schematic diagram of the overall structure of the utility model from a side perspective.

[0019] Figure 5 This is a schematic diagram of the phase-locked crystal oscillator of the utility model.

[0020] Figure 6 The utility model is a circuit diagram of a phase-locked crystal oscillator.

[0021] In the figure: 1. PCB board; 11. Positioning part; 2. Metal shell; 21. Positioning piece; 3. Component assembly; 31. Resistor patch; 32. Capacitor patch; 33. Phase-locked loop; 34. Transistor; 35. Crystal; 36. LDO regulator; 37. Gate circuit. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. The terms such as "upper", "inner", "middle", "left", "right" and "one" used in this specification are only used to facilitate the description and are not used to limit the scope of the present invention. The changes or adjustments in their relative relationships shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0023] An ultra-small phase-locked crystal oscillator, such as Figures 1 to 4 As shown, it includes a PCB board and a component assembly mounted on the PCB board, the PCB board is rectangular, the PCB board is encapsulated with a metal shell, the edge of the PCB board is provided with a positioning portion, the metal shell is cube-shaped, the metal shell has an inner cavity, the inner cavity opening of the metal shell is provided with a positioning piece, the metal shell is connected and positioned with the positioning piece and the positioning portion, the opening edge of the metal shell is close to the edge of the PCB board, so that the opening edge of the metal shell and the edge of the PCB board are basically overlapped, and at this time, the component assembly is accommodated in the inner cavity of the metal shell; wherein, the overall size of the connected PCB board and the metal shell is 14mm*9mm*2.1mm.

[0024] Therefore, by setting a positioning portion on the edge of the PCB board, and the middle position thereof is used for mounting component assemblies, the mounting position of the component assemblies can be more integrated, thereby achieving the effect of reducing the mounting space; at the same time, when the metal shell is installed on the PCB board, the positioning piece of the metal shell can be connected and positioned with the positioning portion of the PCB board, and the component assembly can be covered with the inner cavity of the metal shell, thereby reducing the overall volume of the connected PCB board and the phase-locked crystal oscillator of the metal shell.

[0025] In this embodiment, Figure 2 and Figure 3As shown, in order to improve the connection and positioning stability of the metal shell, the number of positioning parts is two, and the two positioning parts are respectively located at two vertex positions of the opposite edges of the PCB board, the number of positioning members is two, and the two positioning members are respectively located at two vertex positions of the opposite edges in the opening of the metal shell, and the two positioning members of the metal shell correspond to the two positioning parts of the PCB board respectively. Thus, the metal shell is connected and positioned with the two positioning parts of the PCB board through the two positioning members, so that the connection point position is evenly stressed, thereby improving the advantage of installation stability.

[0026] In this embodiment, the positioning member and the positioning portion can be connected and positioned in the following two ways:

[0027] 1) The positioning portion includes a positioning notch opened at the edge of the PCB board. When the positioning notch is opened, it will avoid the connection position of the relevant component assembly in the PCB. The positioning piece includes a positioning block integrally connected to the opening edge of the metal shell. The positioning block is plugged and adapted to the positioning notch. The positioning block is welded and fixed in the positioning notch, so that the opening edge of the metal shell is close to the edge of the PCB board, and the component assembly is accommodated in the inner cavity of the metal shell.

[0028] 2) The positioning portion includes a magnetic patch embedded in the edge of the PCB board, and the positioning piece includes a metal protrusion integrally connected to the opening edge of the metal shell, the metal protrusion is magnetically fixed to the magnetic patch, and the metal protrusion is welded and fixed to the magnetic patch, so that the opening edge of the metal shell is close to the edge of the PCB board, and the component assembly is stored in the inner cavity of the metal shell.

[0029] In this embodiment, Figures 1 to 3 As shown, the component assembly includes resistor patches, capacitor patches, phase-locked loops, transistors, crystals, LDO regulators, and gate circuits mounted on the PCB. The number of resistor patches, capacitor patches, and transistors is limited according to the model and function of the phase-locked crystal oscillator. During the mounting process, each component assembly is mounted according to the position of the component on the component board diagram, and then each component assembly is fixed on the PCB by reflow soldering.

[0030] In this embodiment, the crystal uses a 3525 chip crystal. Since the 3525 chip crystal has the advantages of high precision, high reliability, low power consumption and small size, the use of this crystal can further reduce the overall size of the phase-locked crystal oscillator, while improving the high precision and reliability of the oscillator.

[0031] At the same time, the resistor patch and capacitor patch of this embodiment are both packaged in 0201; the 0201 package is a packaging form of a very small chip capacitor or chip resistor, with a size of 0.6mm*0.3mm, which is suitable for circuit designs with high space requirements; thus, the use of resistor patches and capacitor patches in the form of 0201 packages can reduce the overall volume of the phase-locked crystal oscillator.

[0032] In summary, the ultra-small phase-locked crystal oscillator of the utility model is provided with a positioning portion on the edge of the PCB board, and the middle position thereof is used for mounting component assemblies, so that the mounting position of the component assemblies is more integrated, thereby achieving the effect of reducing the mounting space, and at the same time, a positioning piece corresponding to the positioning portion is provided through the opening edge of the metal shell, and the positioning piece of the metal shell is connected and positioned with the positioning portion of the PCB board so that the component assemblies can be accommodated in the metal shell, thereby reducing the overall structural integration volume of the phase-locked crystal oscillator of the PCB board and the metal shell.

[0033] Based on the above structure of the phase-locked crystal oscillator of the utility model, as Figure 5 and Figure 6 As shown, the working principle of the phase-locked crystal oscillator is further introduced as follows:

[0034] The PCB board of the utility model and the corresponding component assembly form a corresponding crystal oscillator, and the crystal oscillator includes a phase-locked loop, a voltage-controlled oscillator, an amplifier circuit (i.e., the above-mentioned triode), a reference crystal oscillator (i.e., the above-mentioned crystal, which is a 100M crystal in this embodiment), a voltage stabilizing circuit (i.e., the above-mentioned LDO voltage regulator), and a waveform conversion circuit; wherein the voltage-controlled oscillator, the reference crystal oscillator, and the voltage stabilizing circuit are all electrically connected to the phase-locked loop, the voltage stabilizing circuit is electrically connected to the reference crystal oscillator, and the voltage-controlled oscillator, the voltage stabilizing circuit, and the waveform conversion circuit are electrically connected to the amplifier circuit (i.e., Figure 5 and Figure 6 shown).

[0035] Therefore, when working, the phase-locked loop circuit compares the phase of the 20MHz reference frequency output by the reference crystal oscillator and the 100MHz frequency output by the voltage-controlled oscillator, and then outputs the voltage to the voltage-controlled oscillator VCXO, so that the VCXO can provide a 100MHz frequency to the amplifier output circuit more stably. The 100MHz high-frequency signal is amplified after passing through the amplifier circuit, and the square wave signal is output. The LC and π-type filter circuits of the output circuit process the square wave into a sine wave, and then output a stable and high-power high-frequency 100MHz signal. The voltage stabilizing circuit provides a stable 3.3V operating voltage to each level of the unit circuit.

[0036] Based on the working principle of the phase-locked crystal oscillator, the ultra-small phase-locked crystal oscillator of the utility model has the following beneficial effects:

[0037] 1. Based on the frequency oscillation circuit design of the phase-locked circuit-voltage controlled oscillator (VCO), the frequency temperature stability index of the crystal oscillator is better than ±0.5ppm within the temperature range (-40℃~85℃) in a miniaturized volume (14.2mm×9.2mm×3.0mm).

[0038] 2. The 100MHz high-stability crystal oscillator source is realized by frequency division phase-locked technology. The frequency accuracy index is significantly improved after locking, and the frequency accuracy reaches 5-7 orders of magnitude, which improves the frequency stability and has high measurement accuracy.

[0039] 3. The aging index of the phase-locked crystal oscillator meets 0.02ppm / day, and the phase noise is better than -140dBc / Hz@1KHz.

[0040] 4. The crystal uses 3525 chip crystal, and the resistors and capacitors use 0201 package chip resistors and capacitors. They can be directly mounted using a chip mounter without manual mounting and welding, simplifying the processing technology.

[0041] 5. The phase-locked crystal oscillator adopts a single-layer PCB structure of SMD devices, which is conducive to circuit layout and device selection, effectively reducing space without affecting performance.

[0042] 6. The product dimensions of the phase-locked crystal oscillator are length: 14.2±0.2mm, width: 9.2±0.2mm, height: 3.0mm, which meet the customer's requirements for appearance dimensions, and the performance indicators also meet customer needs.

[0043] 7. The phase-locked crystal oscillator is easy and quick to install, easy to mass produce, low cost, and also easy to maintain and handle.

[0044] The implementation methods of the utility model are not limited to this. According to the above content of the utility model, by using common technical knowledge and customary means in the field, without departing from the above basic technical ideas of the utility model, the utility model can also make other various forms of modification, replacement or combination, all of which fall within the scope of protection of the utility model.

Claims

1. An ultra-small phase-locked crystal oscillator, comprising a PCB board and a component assembly mounted on the PCB board, characterized in that: The PCB board is encapsulated with a metal shell, a positioning portion is provided at the edge of the PCB board, a positioning piece is provided at the opening of the metal shell, the metal shell is connected and positioned with the positioning portion through the positioning piece, the opening edge of the metal shell is close to the edge of the PCB board, and the component assembly is accommodated in the metal shell; the overall size of the PCB board and the metal shell is 14mm*9mm*2.1mm.

2. The ultra-small phase-locked crystal oscillator according to claim 1, characterized in that: The positioning portion includes a positioning notch provided at the edge of the PCB board, and the positioning member includes a positioning block provided at the opening edge of the metal shell, the positioning block is adapted to the positioning notch, and the positioning block is welded and fixed in the positioning notch.

3. The ultra-small phase-locked crystal oscillator according to claim 1, characterized in that: The positioning portion includes a magnetic patch embedded in the edge of the PCB board, and the positioning member includes a metal protrusion arranged on the opening edge of the metal shell. The metal protrusion is magnetically fixed on the magnetic patch, and the metal protrusion is welded and fixed on the magnetic patch.

4. The ultra-small phase-locked crystal oscillator according to any one of claims 1 to 3, characterized in that: There are two positioning parts, which are respectively located at two vertex angles of opposite edges of the PCB board; there are two positioning pieces, which are respectively located at two vertex angles of opposite edges in the opening of the metal shell; and the two positioning pieces of the metal shell correspond to the two positioning parts of the PCB board respectively.

5. The ultra-small phase-locked crystal oscillator according to claim 1, characterized in that: The component assembly includes a resistor patch, a capacitor patch, a phase-locked loop, a triode, a crystal, an LDO regulator and a gate circuit mounted on the PCB board.

6. The ultra-small phase-locked crystal oscillator according to claim 5, characterized in that: The crystal is a 3525 chip crystal.

7. The ultra-small phase-locked crystal oscillator according to claim 5, characterized in that: The resistor patch and capacitor patch are both packaged in 0201.

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