JP2018142899A - Crystal oscillator - Google Patents

Abstract

Disclosed is a crystal oscillator that is reduced in size and free from the problem of heat treatment and in which the influence of heat of a frequency control circuit on a temperature compensation circuit and a crystal resonator is reduced. In an oscillator, a packaged crystal resonator, a temperature compensation circuit provided on the upper surface thereof, and a frequency control circuit are disposed in a plane of a ceramic base with a bypass capacitor interposed therebetween. The temperature compensation circuit 4 and the crystal resonator 2 are not easily affected by the heat of the frequency control circuit 3, and the crystal resonator 1 and the temperature compensation circuit 4 are in close contact with each other. Operates by reflecting the temperature of the crystal unit 1. [Selection] Figure 1

Description

  The present invention relates to a crystal oscillator, and more particularly, to a crystal oscillator that can be reduced in size, can be free from heat treatment problems, and can reduce the influence of the heat of a crystal resonator on a frequency control circuit.

[Conventional technology]
The conventional communication protocol NTP (Network Time Protocol) has a hierarchical structure called Stratum, and a highly accurate temperature-compensated crystal oscillator (TCXO) to comply with the Stratum 3 standard, The operating frequency of the integrated circuit (IC) is up to about 60 MHz.
For this reason, when an output frequency exceeding 60 MHz is required, it is necessary to multiply the output frequency, thereby increasing the outer shape of the oscillator.

  In addition, in order to cope with high accuracy, measures to improve aging and hysteresis are generally taken, such as heat treatment of crystal units, but when a crystal blank is mounted in the same cavity as the IC In addition, there is a concern that the IC may be damaged by the heat treatment.

[Related technologies]
As related prior arts, Japanese Unexamined Patent Application Publication No. 2006-134636 “Oscillator, Electronic Device and Moving Body” (Seiko Epson Corporation) [Patent Document 1], Japanese Unexamined Patent Application Publication No. 2007-013569 “Piezoelectric Oscillator” (Kyocera Kinseki) Co., Ltd.) [Patent Document 2], Japanese Patent No. 3841304, “Piezoelectric Oscillator and Manufacturing Method Therefor” (Seiko Epson Corporation) [Patent Document 3].

Patent Document 1 discloses an oscillator in which a crystal resonator, an oscillation IC, and a control IC are arranged on a mounting substrate.
Patent Document 2 discloses a piezoelectric oscillator in which a piezoelectric vibrator packaged on a substrate having a cavity structure and an integrated circuit element are mounted.
Patent Document 3 discloses a piezoelectric oscillator in which an IC chip is mounted on a packaged piezoelectric vibrator.

Japanese Patent Application Laid-Open No. 2006-134736 JP 2007-013569 A Japanese Patent No. 3841304

  However, the conventional crystal oscillator has a problem in that it requires a separate multiplication circuit, which increases the shape, and the IC may be damaged by the heat treatment of the crystal resonator.

  The present invention has been made in view of the above circumstances, and is a crystal oscillator that is downsized, has no heat treatment problems, and further reduces the influence of the heat of the frequency control circuit on the temperature compensation circuit and the crystal unit. The purpose is to provide.

  The present invention for solving the problems of the above-described conventional example is a crystal oscillator having a concave ceramic base, wherein the package is arranged on one half of the inner plane inside the concave shape of the ceramic base. And a frequency control circuit disposed on the other half of the plane, and a temperature compensation circuit provided on the crystal resonator.

  The present invention is characterized in that in the above-described crystal oscillator, the crystal resonator and the temperature compensation circuit are bonded with a heat conductive adhesive.

  The present invention is characterized in that in the crystal oscillator, a bypass capacitor connected between a power source and a ground is disposed between the crystal resonator and the frequency control circuit.

  According to the present invention, the quartz resonator is provided with a concave ceramic base, and the packaged crystal resonator is disposed on one half of the inner flat surface inside the concave shape of the ceramic base, and the other half of the flat surface is disposed. Since the frequency control circuit is arranged and the crystal oscillator is provided with the temperature compensation circuit on the crystal unit, it can be downsized and there is no problem of heat treatment, and the temperature control circuit and the frequency control circuit to the crystal unit There is an effect that the influence of heat can be reduced.

It is a plane explanatory view of this oscillator. It is a cross-sectional explanatory view of the present oscillator.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
In the crystal oscillator according to the embodiment of the present invention, in the plane of the concave cavity, the packaged crystal oscillator is arranged in half, the frequency control circuit is arranged in the other half, and the crystal oscillator Since the temperature compensation circuit is provided in the cavity, the crystal resonator, the frequency control circuit and the temperature compensation circuit can be accommodated in the cavity to reduce the size, and by separating the crystal resonator and the frequency control circuit, The temperature control circuit and the crystal unit are not affected by the heat of the frequency control circuit, and the crystal unit that has been heat-treated and inspected is mounted. Can be prevented.

[Oscillator: Fig. 1 and Fig. 2]
A crystal oscillator (present oscillator) according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory plan view of the present oscillator, and FIG. 2 is a sectional explanatory view of the present oscillator.
As shown in FIGS. 1 and 2, this oscillator has a cavity in which the ceramic base 1 has a concave shape, and a packaged crystal resonator 2 and a frequency control circuit 3 are disposed on the inner plane. Further, a temperature compensation circuit 4 is provided on the crystal unit 2, and a lid 6 as a lid is provided on the upper surface.

[Each oscillator part]
Next, each part of the oscillator will be described.
The ceramic base 1 forms a cavity structure by laminating a plurality of ceramic plates.
On the plane of the ceramic base 1 (bottom surface inside the cavity), metal electrodes and wiring patterns are formed, and lead lines to the outside are also formed.

The crystal unit 2 is a package in which a crystal blank that has already been heat-treated is contained in a package.
A metal electrode is formed on the bottom surface of the crystal unit 2 and connected to the metal electrode of the ceramic base 1 by soldering.
The crystal resonator 2 is disposed in the left half (one half) region of the plane of the ceramic base 1 in FIG.

The frequency control circuit 3 is a circuit that controls the oscillation frequency and performs multiplication or the like, and is, for example, a PLL (Phase Locked Loop) IC or the like.
The frequency control circuit 3 is arranged in the right half (the other half) region of the plane of the ceramic base 1 in FIG.

The temperature compensation circuit 4 is, for example, an IC for TCXO.
The IC is an oscillation circuit having a temperature compensation function, and includes a temperature sensor, a temperature compensation circuit, a crystal oscillation circuit, and the like. Here, the IC is referred to as a “temperature compensation circuit”.
Since the temperature sensor in the IC is configured to contact (adhere) the crystal resonator 2, the temperature difference between the crystal blank in the crystal resonator 2 and the temperature sensor can be reduced.

The temperature compensation circuit 4 is bonded on the crystal resonator 2 with a heat conductive adhesive.
The thermally conductive adhesive is an adhesive having a high thermal conductivity. For example, silver (Ag) is contained as a metal powder having a high thermal conductivity in a silicon resin.
Thereby, the heat of the crystal unit 2 is easily transmitted to the temperature compensation circuit 4, and the temperature compensation circuit 4 can appropriately perform the temperature compensation.

The bypass capacitor 5 is connected between the power supply and the ground, bypasses the noise superimposed on the DC power supply, supplies a stable power supply voltage, and prevents fluctuations in the power supply voltage supplied to the IC. is there.
The bypass capacitor 5 is disposed between the crystal resonator 2 and the frequency control circuit 3.

[Production method]
In the cavity of the ceramic base 1 of the cavity, a crystal resonator 2, a frequency control circuit 3 for performing multiplication, a capacitor 5 and a temperature compensation circuit 4 are mounted, and each component is connected to the electrode of the ceramic base 1 by wire bonding. Then, the lid 6 is provided on the upper surface.

That is, the crystal oscillator can be miniaturized by mounting necessary parts on the plane of the cavity of the ceramic base 1.
The conventional H structure with parts placed on the front and back of the ceramic base is bulky in the height direction, the structure is complicated, and in addition, it is necessary to inject resin, but this oscillator is bulky in the height direction. In addition, since it is not necessary to enclose the resin, the manufacturing process is simple and the manufacturing cost can be reduced.

  In addition, in a conventional crystal oscillator, after mounting an IC on a substrate, a crystal blank is mounted, and when a crystal becomes defective in a DLD (Drive Level Dependency) inspection, temperature characteristic inspection, etc. , Non-defective ICs were also discarded along with the crystal units. However, because this oscillator is equipped with inspected non-defective packaged crystal units, the non-defective ICs are discarded due to defects caused by the crystal units. Thus, the defect cost can be reduced.

  In addition, in the conventional oscillator, when the product size is increased, the temperature characteristics of the TCXO alone are difficult to be reproduced due to the influence of mounting, load, and the like, and it is difficult to achieve high accuracy. Since the temperature characteristics can be adjusted with the temperature compensation circuit 4 mounted thereon, a small and highly accurate high-frequency TCXO can be realized.

[Effect of the embodiment]
According to the present oscillator, the packaged crystal resonator 2, the temperature compensation circuit 4 provided on the upper surface thereof, and the frequency control circuit 3 are arranged in the plane of the ceramic base 1 with the bypass capacitor 5 interposed therebetween. Therefore, the frequency control circuit 3 is not easily affected by the heat of the crystal resonator 1 and the crystal resonator 1 and the temperature compensation circuit 4 are in close contact with each other, so that the temperature compensation circuit 4 becomes a crystal resonator. In addition, there is an effect that it is possible to realize a compact oscillator that does not increase in the height direction in the cavity in a compact manner.

  The present invention is suitable for a crystal oscillator that is miniaturized, has no heat treatment problem, and has less influence of heat from the frequency control circuit on the temperature compensation circuit and the crystal resonator.

  DESCRIPTION OF SYMBOLS 1 ... Ceramic base, 2 ... Crystal oscillator, 3 ... Frequency control circuit, 4 ... Temperature compensation circuit, 5 ... Bypass capacitor, 6 ... Lid

Claims (3)

A crystal oscillator comprising a concave ceramic base,
Inside the concave shape of the ceramic base, a packaged crystal resonator disposed on one half of the inner plane; and
A frequency control circuit disposed on the other half of the plane;
A crystal oscillator comprising a temperature compensation circuit provided on the crystal resonator.   2. The crystal oscillator according to claim 1, wherein the crystal resonator and the temperature compensating circuit are bonded with a heat conductive adhesive.   3. The crystal oscillator according to claim 1, wherein a bypass capacitor connected between the power source and the ground is disposed between the crystal resonator and the frequency control circuit.