Low-phase noise quartz crystal oscillator with double-layer packaging structure

Abstract

The utility model discloses a low-phase noise quartz crystal oscillator with a double-layer packaging structure, which comprises a metal base and a PCB (Printed Circuit Board) arranged at the top of the metal base, and further comprises an outer layer packaging mechanism, an inner layer packaging mechanism, a lower layer packaging mechanism and an upper layer packaging mechanism, the inner-layer packaging mechanism comprises a low-phase noise quartz crystal oscillator body arranged on the PCB, the low-phase noise quartz crystal oscillator body is composed of a ceramic base, a crystal plate, an IC integrated circuit and a gold thread, the IC integrated circuit is fixed on the ceramic base, and the gold thread is fixed on the ceramic base. And two ends of the gold thread are respectively connected with the ceramic base and the IC integrated circuit. According to the low-phase noise quartz crystal oscillator with the double-layer packaging structure provided by the utility model, the influence of external signal interference and power supply noise on internal oscillation is effectively reduced, and the oscillation stability is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of quartz crystal oscillation, in particular to a low phase noise quartz crystal oscillator with a double-layer packaging structure. Background Art

[0002] The clock signal plays a very important role in the circuit. It provides a reference clock for the chip and directs the chip to run in an orderly and step-by-step manner. At the same time, it is also the oscillator source of the carrier signal in the RF field, providing the carrier signal for wireless communication. The stability of the clock signal is related to whether the chip or the system composed of the chip can run stably and reliably.

[0003] At present, the market can provide stable active clock products such as quartz crystal oscillators, MEMS silicon oscillators, rubidium clocks, cesium atomic clocks, etc. Each of these products has its own advantages and disadvantages. From the perspective of product clock accuracy, rubidium clocks and cesium atomic clocks have better frequency stability, but they are expensive. Quartz crystal oscillators and MEMS silicon oscillators have very good cost performance and are widely used in various consumer and industrial control electronic products.

[0004] With the rapid development of electronic technology, electronic products have higher and higher requirements for the stability of clock signals, especially some high-speed communication products, HIFI high-fidelity audio products, etc., which have higher requirements for the phase noise of clock signals. Phase noise is an important microscopic indicator to measure clock stability. Any periodic clock signal has a phase-frequency characteristic, that is, frequency and phase are related, and changes in phase will lead to changes in frequency. Therefore, the stability of phase can reflect the stability of frequency, and clock products with low phase noise are becoming more and more popular.

[0005] Compared with MEMS silicon oscillators, quartz crystal oscillators have a natural advantage in phase noise, which is due to the difference in oscillation source materials. Quartz crystal oscillators use quartz wafers as oscillation source materials, and their inherent frequency is more stable; however, the demand for clock stability in electronic products is getting higher and higher. Oscillators made of quartz wafers, product structural design and production process, and the matching of quartz wafers and oscillation chips determine the phase noise of the product. Therefore, a low phase noise quartz crystal oscillator with a double-layer packaging structure is urgently needed to optimize the phase noise of the oscillator and solve the above problems. Utility Model Content

[0006] The utility model discloses a low phase noise quartz crystal oscillator with a double-layer packaging structure, aiming to solve the technical problems of phase noise deterioration and power supply ripple effect on phase noise of a traditional single-layer packaging quartz crystal oscillator after SMT high-temperature reflow soldering.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A low phase noise quartz crystal oscillator with a double-layer packaging structure comprises a metal base and a PCB board mounted on the top of the metal base, and further comprises: an outer packaging mechanism: the outer packaging mechanism is arranged on the PCB board; an inner packaging mechanism: the inner packaging mechanism comprises a low phase noise quartz crystal oscillator body arranged on the PCB board, the low phase noise quartz crystal oscillator body comprises: a ceramic base, a crystal piece, an IC integrated circuit and a gold wire, the IC integrated circuit is fixed on the ceramic base, two ends of the gold wire are respectively connected to the ceramic base and the IC integrated circuit, the crystal piece is bonded to the ceramic base, and a power supply filter element is attached to the PCB board by SMT method.

[0009] In this scheme, a double-layer packaging structure formed by an outer packaging mechanism and an inner packaging mechanism can effectively reduce the influence of external wall noise on the low phase noise quartz crystal oscillator body. A PCB board is used internally, and power supply filtering components are added. This can effectively remove the influence of power supply noise on internal oscillation. The crystal piece and IC integrated circuit sealing technology are used in the low phase noise quartz crystal oscillator body, which greatly shortens the line routing and reduces the signal reflection caused by impedance discontinuity of the clock routing.

[0010] In a preferred solution, the outer packaging mechanism includes a metal shell arranged on the top of the metal base, and the metal shell is used to surround the inner packaging mechanism.

[0011] By setting up a metal shell and a metal bottom plate, external signal interference can be well shielded in the outer packaging structure. At the same time, from the outermost packaging, the influence of high temperature on the phase noise parameters of the internal low phase noise quartz crystal oscillator body can be reduced when the user is in use.

[0012] As can be seen from the above, a low phase noise quartz crystal oscillator with a double-layer packaging structure includes a metal base and a PCB board installed on the top of the metal base, and also includes: an outer packaging mechanism: the outer packaging mechanism is arranged on the PCB board; an inner packaging mechanism: the inner packaging mechanism includes a low phase noise quartz crystal oscillator body arranged on the PCB board, and the low phase noise quartz crystal oscillator body is composed of: a ceramic base, a crystal piece, an IC integrated circuit and a gold wire, the IC integrated circuit is fixed on the ceramic base, the two ends of the gold wire are respectively connected to the ceramic base and the IC integrated circuit, the crystal piece is bonded to the ceramic base, and the PCB board is bonded with a power supply filter element by SMT. The low phase noise quartz crystal oscillator with a double-layer packaging structure provided by the utility model effectively reduces the influence of external signal interference and power supply noise on internal oscillation, and ensures the stability of oscillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the outer packaging structure of a low phase noise quartz crystal oscillator with a double-layer packaging structure proposed by the utility model.

[0014] Figure 2 This is a top view of the interior of the outer package of a low phase noise quartz crystal oscillator with a double-layer packaging structure proposed by the utility model.

[0015] Figure 3 This is a top view of the inner layer package of a low phase noise quartz crystal oscillator with a double-layer package structure proposed by the utility model.

[0016] Figure 4 This is a cross-sectional side view of the inner layer package of a low phase noise quartz crystal oscillator with a double-layer package structure proposed by the utility model.

[0017] Figure 5 The utility model provides a schematic diagram of the solder pad installation structure of a low phase noise quartz crystal oscillator with a double-layer packaging structure.

[0018] Figure 6 This is a schematic circuit diagram of a low phase noise quartz crystal oscillator body in an inner package of a low phase noise quartz crystal oscillator with a double-layer packaging structure proposed by the utility model.

[0019] In the attached figure: 1. Metal base; 2. Metal shell; 3. PCB board; 301. Power supply filter element; 302. Low phase noise quartz crystal oscillator body; 4. Ceramic base; 5. Crystal piece; 6. Electrode; 7. Conductive glue; 8. Gold wire; 9. Top cover; 10. IC integrated circuit; 11. Solder pad. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application usually described and marked in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0021] The utility model discloses a low phase noise quartz crystal oscillator with a double-layer packaging structure, which is mainly used in scenarios where electronic products have high requirements on clock stability, especially requirements on low clock phase noise.

[0022] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , a low phase noise quartz crystal oscillator with a double-layer packaging structure, comprising a metal base 1 and a PCB board 3 mounted on the top of the metal base 1, and further comprising: an outer packaging mechanism: the outer packaging mechanism is arranged on the PCB board 3;

[0023] Inner packaging mechanism: The inner packaging mechanism includes a low phase noise quartz crystal oscillator body 302 arranged on the PCB board 3. The low phase noise quartz crystal oscillator body 302 is composed of: a ceramic base 4, a crystal piece 5, an IC integrated circuit 10 and a gold wire 8. The IC integrated circuit 10 is fixed on the ceramic base 4. The two ends of the gold wire 8 are respectively connected to the ceramic base 4 and the IC integrated circuit 10. The crystal piece 5 is bonded to the ceramic base 4. The power supply filter element 301 is attached to the PCB board 3 by SMT.

[0024] It should be noted that the IC integrated circuit 10 has a three-point oscillation circuit composed of an inverting amplifier integrated inside. The circuit is connected to the crystal piece 5. The frequency output by the inverting amplifier is shaped by the inverter, output to the frequency divider, and then output to the three-state controller; the other way is output to the oscillation waveform detection circuit, which is used to detect whether the frequency amplitude output by the inverting amplifier is stable. If it is stable, it outputs a high level, and if it is unstable, it outputs a low level. The high and low levels of the output are connected to the three-state controller to control whether the three-state controller outputs the frequency externally. The purpose of this method is to make the oscillator not output the frequency externally when it is not stable at the moment of power-on, thereby improving the frequency output reliability of the product. In actual use, the double-layer packaging structure formed by the outer packaging mechanism and the inner packaging mechanism can effectively reduce the influence of the external wall noise on the low phase noise quartz crystal oscillator body 302.

[0025] At the same time, the internal PCB board 3 is used, and the power supply filter element 301 is added, which can effectively remove the influence of power supply noise on internal oscillation. The crystal piece 5 and IC integrated circuit 10 sealing technology are used in the low phase noise quartz crystal oscillator body 302, which greatly shortens the line routing and reduces the signal reflection caused by impedance discontinuity of the clock routing.

[0026] Reference Figure 1 and Figure 4 In a preferred embodiment, an electrode 6 is provided above the crystal piece 5, and the electrode 6 is connected to the ceramic base 4. A conductive glue 7 is provided on one side of the top outer wall of the crystal piece 5, and one end of the electrode 6 is also connected to the conductive glue 7. The conductive glue 7 is used to conduct the crystal piece 5, the electrode 6 and the ceramic base 4. Solder pads 11 are provided at the four corners of the bottom outer wall of the ceramic base 4. The low phase noise quartz crystal oscillator body 302 is connected to the PCB board 3 through the soldering pads 11. A top cover 9 is provided on one side of the top outer wall of the low phase noise quartz crystal oscillator body 302. The top cover 9 is located directly above the crystal piece 5, and the inner layer is encapsulated by the top cover 9.

[0027] Reference Figure 3 , Figure 4 and Figure 5 In a preferred embodiment, the outer packaging mechanism includes a metal shell 2 arranged on the top of the metal base 1, and the metal shell 2 is used to surround the inner packaging mechanism.

[0028] Specifically, by providing a metal shell 2 and a metal base plate, external signal interference can be well shielded in the outer packaging structure. At the same time, from the outermost packaging, the influence of high temperature on the phase noise parameters of the internal low phase noise quartz crystal oscillator body 302 can be reduced when the user is in use.

[0029] Reference Figure 1In a preferred embodiment, metal leads and insulating blocks are respectively provided on both sides of the outer wall of the bottom of the metal base 1 , and the metal leads are connected to the PCB board 3 .

[0030] Reference Figure 6 In the attached figure, U1, Rf, Cd, Cg, and Y1 constitute a three-point oscillation circuit, which is the oscillation source of the product.

[0031] Among them, Y1 is a crystal piece 5 with an electrode 6 attached, which constitutes a crystal resonator; U1 is a reverse amplifier, which provides amplitude and phase conditions for the oscillation circuit; Rf is a feedback resistor, which makes the reverse amplifier work in the linear amplification area, Gg and Cd are the load capacitors of the oscillation circuit, and are also two necessary capacitors to form a three-point oscillation circuit. The frequency output by the inverter U1 is buffered and output through the U2 inverter. The frequency output by U2 is divided according to user needs through the U3 divider to facilitate low-frequency output. The frequency output by U3 is finally output through the U4 end buffer with three-state control to better isolate the impact of the load on the oscillation circuit. The U5 oscillator signal detection unit is used to detect whether the oscillator is oscillating to control the three-state controller.

[0032] Working principle: When in use, the metal shell 2 and the metal bottom plate can well shield the external signal interference in the outer packaging structure. At the same time, the PCB board 3 is used inside and the power supply filter element 301 is added, which can well remove the influence of the power supply noise on the internal oscillation. The crystal piece 5 and the IC integrated circuit 10 sealing technology are adopted in the low phase noise quartz crystal oscillator body 302, which greatly shortens the line routing and reduces the signal reflection caused by the impedance discontinuity of the clock routing, thereby ensuring the stability of the use of the low phase noise quartz crystal oscillator body 302.

[0033] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model is not limited to this. The replacement can be a replacement of part of the structure, device, method step, or a complete technical solution. Equivalent replacement or change based on the technical solution of the utility model and its utility model concept should be included in the protection scope of the utility model.

Claims

1. A low phase noise quartz crystal oscillator with a double-layer packaging structure, comprising a metal base (1) and a PCB board (3) mounted on top of the metal base (1), characterized in that: Also includes: Outer packaging mechanism: the outer packaging mechanism is arranged on the PCB board (3); Inner packaging mechanism: the inner packaging mechanism comprises a low phase noise quartz crystal oscillator body (302) arranged on the PCB board (3), the low phase noise quartz crystal oscillator body (302) comprising: a ceramic base (4), a crystal piece (5), an IC integrated circuit (10) and a gold wire (8), the IC integrated circuit (10) being fixed on the ceramic base (4), the two ends of the gold wire (8) being respectively connected to the ceramic base (4) and the IC integrated circuit (10), the crystal piece (5) being bonded to the ceramic base (4), and a power supply filter element (301) being bonded to the PCB board (3) by means of SMT.

2. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 1 is characterized in that: An electrode (6) is provided above the crystal sheet (5), and the electrode (6) is connected to the ceramic base (4).

3. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 2 is characterized in that: A conductive glue (7) is provided on one side of the top outer wall of the crystal sheet (5), and one end of the electrode (6) is also connected to the conductive glue (7). The conductive glue (7) is used to conduct electricity between the crystal sheet (5), the electrode (6) and the ceramic base (4).

4. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 3 is characterized in that: Solder pads (11) are provided at the four corners of the outer wall of the bottom of the ceramic base (4), and the low phase noise quartz crystal oscillator body (302) is connected to the PCB board (3) via the solder pads (11).

5. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 4 is characterized in that: A top cover (9) is provided on one side of the top outer wall of the low phase noise quartz crystal oscillator body (302), and the top cover (9) is located directly above the crystal plate (5).

6. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 1, characterized in that: The outer packaging mechanism comprises a metal shell (2) arranged on the top of the metal base (1), and the metal shell (2) is used to surround the inner packaging mechanism.

7. The low phase noise quartz crystal oscillator with a double-layer packaging structure according to claim 6, characterized in that: Metal leads and insulating blocks are respectively provided on both sides of the outer wall of the bottom of the metal base (1), and the metal leads are connected to the PCB board (3).

Images