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CN-121997397-A - Microminiaturization design method for high-precision temperature compensation crystal oscillator

CN121997397ACN 121997397 ACN121997397 ACN 121997397ACN-121997397-A

Abstract

The invention discloses a microminiaturization design method of a high-precision temperature compensation crystal oscillator, which belongs to the technical field of temperature compensation crystal oscillator design, and comprises a microminiaturization design of a multilayer surface-mounted ceramic base, a design of a metal cover plate, a microminiaturization design of a quartz oscillator and a microminiaturization design of an integrated circuit temperature compensation chip, wherein the microminiaturization design of the multilayer surface-mounted ceramic base comprises an SMD3225 type package, the design of the metal cover plate comprises an integrated package with the multilayer surface-mounted ceramic base, and the microminiaturization design of the quartz oscillator comprises a miniature rectangular quartz wafer which is cut by AT and has a high Q value. The design method successfully reduces the main flow packaging size of the temperature compensation crystal oscillator from SMD5032 to SMD3225 by adopting the innovative multilayer surface-mounted ceramic base, the ultra-small-size quartz oscillator and the miniaturized temperature compensation chip, thereby meeting the urgent requirement of modern electronic equipment on the weight reduction and the miniaturization of a core frequency source. Meanwhile, the metal cover plate and the ceramic base are sealed by adopting resistance parallel welding, so that the leakage rate of the device is obviously reduced.

Inventors

  • XIA QI
  • ZHENG WENQIANG
  • CUI WEI
  • DUAN YOUFENG
  • HUI JIANPING
  • LIU XIAOGUANG

Assignees

  • 北京无线电计量测试研究所

Dates

Publication Date
20260508
Application Date
20251226

Claims (8)

  1. 1. The high-precision temperature compensation crystal oscillator microminiaturization design method is characterized by comprising microminiaturization design of a multilayer surface-mounted ceramic base (1), design of a metal cover plate (2), microminiaturization design of a quartz vibrator (3) and microminiaturization design of an integrated circuit temperature compensation chip (4); The miniaturized design of the multilayer surface-mounted ceramic base (1) comprises adopting an SMD3225 type package; the design of the metal cover plate (2) comprises the adoption of integrated packaging between the metal cover plate and the multilayer surface-mounted ceramic base (1); The microminiaturization design of the quartz vibrator (3) comprises selecting a small rectangular quartz wafer with AT cutting and high Q value; the miniaturized design of the integrated circuit temperature compensation chip (4) comprises the construction of a CMOS LSI structure.
  2. 2. The miniaturized design method of the high-precision temperature compensation crystal oscillator according to claim 1, wherein the miniaturized design of the multilayer surface-mounted ceramic base (1) further comprises: The multilayer surface-mounted ceramic base (1) is designed to be 5 layers, and the back of the 5 th layer is provided with 4 gold-plated leading-out ends which are the functional leading-out ends of the high-precision temperature compensation crystal oscillator; the 4 gold-plated leading-out ends are respectively power supply, ground, output and debugging, the 3 rd layer and the 4 th layer of the multilayer surface-mounted ceramic base (1) are led into the cavity of the multilayer surface-mounted ceramic base by means of up-down through and wiring conduction, and the 2 nd layer comprises at least two gold-plated platforms for bonding the quartz vibrator (3); The gold plating platform is connected with the 3 rd layer wiring, the 4 th layer wiring and the 5 th layer gold plating leading-out end of the multilayer surface-mounted ceramic base (1) in a vertically through mode, and the 1 st layer of the multilayer surface-mounted ceramic base (1) is a sealing ring.
  3. 3. The miniaturized design method of the high-precision temperature compensation crystal oscillator according to claim 2, wherein the design of the metal cover (2) further comprises: The size of the metal cover (2) is designed to be (2.85 mm plus or minus 0.2 mm) multiplied by (2.15 mm plus or minus 0.2 mm), the metal cover is matched with the size of a sealing ring on the multilayer surface-mounted ceramic base (1), and the metal cover (2) and the multilayer surface-mounted ceramic base (1) are packaged integrally in a resistance parallel welding mode.
  4. 4. The miniaturized design method of the high-precision temperature compensated crystal oscillator according to claim 3, wherein the miniaturized design of the quartz vibrator (3) further comprises: the quartz vibrator (3) is designed to be long multiplied by width= (2 mm plus or minus 0.1 mm) multiplied by (1.3 mm plus or minus 0.1 mm), and the chamfer angle is designed according to the frequency of the quartz wafer; The metal electrode on the quartz vibrator (3) is a rectangular electrode concentric with the quartz wafer, the size is designed to be 0.79mm multiplied by 0.59mm, the line width is 60 mu m, and the size of the bonding pad is 70 mu m multiplied by 70 mu m; Gold is selected as a material of the metal electrode, and a substrate material of the metal electrode is chromium; two end points led out from the edge of the wide side of the quartz vibrator (3) are respectively adhered to the gold plating platform of the multilayer surface-mounted ceramic base (2) through conductive adhesive.
  5. 5. The method for miniaturizing a high-precision temperature compensated crystal oscillator according to claim 4, wherein the miniaturizing the integrated circuit temperature compensated chip (4) further comprises: The integrated circuit temperature compensation chip (4) integrates a temperature sensor, a 5-order voltage function generator, an automatic frequency control circuit, a VCXO circuit and a erasable nonvolatile memory.
  6. 6. The miniaturized design method of the high-precision temperature compensation crystal oscillator according to claim 5, wherein the miniaturized design of the integrated circuit temperature compensation chip (4) further comprises: providing negative impedance of the integrated circuit temperature compensation chip (4) through the voltage-controlled circuit to enable the quartz vibrator (3) to vibrate; The resonance frequency of the quartz vibrator (3) is finely tuned and corrected by providing the external voltage of the integrated circuit temperature compensation chip (4) through an AFC circuit; Compensating for a temperature deviation inherent to the quartz vibrator (3) by a temperature compensation circuit; The temperature compensation coefficient of the temperature compensation circuit is trimmed through the erasable nonvolatile memory so as to adapt to the direct discreteness of different quartz vibrators (3).
  7. 7. The method of claim 6, wherein the temperature compensation circuit integrates a bandgap reference circuit, an adder, and voltage function generators of 1 st, 3 rd, 4 th and 5 th orders.
  8. 8. The miniaturized design method of the high-precision temperature compensation crystal oscillator according to claim 7, wherein the bandgap reference circuit carries out up-and-down translation trimming on the 1 st-order temperature voltage of the 5-order voltage function generator; The adder amplifies, reduces and adjusts the 4 th and 5 th order temperature voltages of the 5 th order voltage function generator; the integrated circuit temperature compensation chip 4 senses the ambient temperature through the temperature sensor, the 5-order voltage function generator generates 1 st-order and 3 rd-5 th-order temperature voltages from the ambient temperature, the 1 st-order and 3 th-5 th-order temperature voltages are added to the voltage-controlled end of the temperature compensation varactor, the integrated circuit temperature compensation chip 4 generates a compensation frequency curve opposite to the frequency of the quartz vibrator (3) along with the temperature change, and the frequency drift of the AT cut quartz vibrator (3) is compensated.

Description

Microminiaturization design method for high-precision temperature compensation crystal oscillator Technical Field The invention belongs to the technical field of temperature compensation crystal oscillator design, and particularly relates to a microminiaturization design method of a high-precision temperature compensation crystal oscillator. Background The crystal oscillator is a key device for time-frequency reference and frequency control of an electronic system because of good frequency stability and high reliability. With the gradual improvement of the performance of electronic devices, higher requirements are also put on the performance index of the crystal oscillator. Crystal oscillators are classified into a constant temperature crystal oscillator, a temperature compensation crystal oscillator, a common crystal oscillator, and the like. The temperature compensation crystal oscillator not only has the characteristics of miniaturization, low power consumption, low cost and the like which are not possessed by the constant-temperature crystal oscillator, but also has the advantages of high accuracy, high stability, low aging rate and the like compared with the common crystal oscillator, becomes a preferred variety of the electronic equipment for selecting a high-precision frequency source, and meets the requirements of accurate and stable signal transmission. The research on the aspects of miniaturization and high reliability of the temperature compensation crystal oscillator is an important direction of the technology iteration of the temperature compensation crystal oscillator. The temperature compensation crystal oscillator with the smallest volume commonly used in the current system is surface-mounted SMD5032 packaging, and in order to achieve the purposes of light weight and miniaturization, the volume and weight of an internal frequency source are required to be further reduced, and meanwhile, high precision and high reliability are maintained. The invention designs a surface-mounted SMD3225 package, namely a miniature high-precision surface-mounted temperature-compensated crystal oscillator with the external dimension of 3.2mm multiplied by 2.5mm multiplied by 1.1mm, the frequency range of 10 MHz-50 MHz, the frequency temperature stability of minus 40 ℃ to minus 85 ℃ is better than +/-1 ppm, and the phase noise is better than-130 dBc/Hz@1kHz. The foregoing is not necessarily a prior art, and falls within the technical scope of the inventors. Disclosure of Invention In order to solve the above problems, the present invention provides a miniaturized design method of a high-precision temperature compensation crystal oscillator, which successfully reduces the main flow packaging size of the temperature compensation crystal oscillator from the SMD5032 to the SMD3225 by adopting an innovative multilayer surface-mounted ceramic base, an ultra-small size quartz oscillator and a miniaturized temperature compensation chip, thereby remarkably reducing the volume and meeting the urgent requirements of modern electronic equipment on the weight and the miniaturization of a core frequency source. Meanwhile, the metal cover plate and the ceramic base are sealed by adopting resistance parallel welding, so that the leakage rate of the device is obviously reduced, and the tightness and the long-term environmental reliability are enhanced. In order to achieve the above purpose, the invention provides a microminiaturization design method of a high-precision temperature compensation crystal oscillator, which comprises the microminiaturization design of a multilayer surface-mounted ceramic base, the design of a metal cover plate, the microminiaturization design of a quartz vibrator and the microminiaturization design of an integrated circuit temperature compensation chip. The miniaturized design of the multilayer surface-mounted ceramic base comprises adopting an SMD3225 type package. The design of the metal cover plate comprises the adoption of integrated packaging between the metal cover plate and the multilayer surface-mounted ceramic base. The miniaturized design of the quartz oscillator comprises a small rectangular quartz wafer which is cut by AT and has a high Q value. The miniaturized design of the integrated circuit temperature compensation chip comprises the construction of a CMOS LSI structure. Preferably, the miniaturized design of the multilayer surface-mounted ceramic base further comprises: The multilayer surface-mounted ceramic base is designed to be 5 layers, and 4 gold-plated leading-out ends are arranged on the back of the 5 th layer and serve as functional leading-out ends of the high-precision temperature compensation crystal oscillator. The 4 gold-plated leading-out ends are respectively power supply, ground, output and debugging, the 3 rd layer and the 4 th layer of the multilayer surface-mounted ceramic base lead the gold-plated leading-out ends into the cavity of the multilayer surface-mounted c