JP3423253B2 - Surface mount crystal oscillator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-mounted crystal oscillator (hereinafter referred to as a surface-mounted oscillator) in an industrial technical field, and particularly to a crystal resonator and a surface-mounted substrate (mounted). (Hereinafter referred to as a substrate). (Background of the Invention) Surface mount oscillators are frequently used in mobile communication devices such as mobile phones and digital control devices such as computers, and their miniaturization is being further promoted. In recent years, there is a device in which a crystal blank and an IC chip for oscillation are housed in separate spaces to reduce the size and economical efficiency (see Japanese Patent Application Laid-Open Nos. 7-106891 and 7-1069).
No. 01, No. 8-204452, No. 9-167918
No. 10-98151). (Example by Applicant) FIGS. 5 and 6 are diagrams for explaining an example of a surface mount oscillator according to the present applicant.
FIG. 5 is a schematic sectional view, and FIG. 6 is an exploded view. The surface-mounted oscillator includes a crystal resonator for surface mounting (referred to as a surface-mounted resonator) 1 and a surface-mounted substrate 2 (referred to as a mounting substrate). The surface mount resonator 1 hermetically encloses a crystal blank 4 in a concave portion of a ceramic base 3 of a laminated type. The ceramic base 3 has a metal ring 5 on the upper surface, and a metal cover 6 is joined by seam welding. The crystal blank 4 has excitation electrodes 7 (ab) on both main surfaces, and extraction electrodes 8 (ab) on both sides of one end.
Is extended (FIG. 7). Then, both ends of one end are fixed by a conductive adhesive 9 and are electrically and mechanically held. [0004] On the back side of the surface mount vibrator 1, a surface mount terminal electrode 10 (a) is passed through a side electrode formed by a through hole.
bcd). Normally, the terminal electrode 10 (ac) provided on the right diagonal diagonal part is connected to a pair of extraction electrodes 8 of the crystal blank 4.
Crystal terminals X1 and X2 connected to (ab). In addition, the terminal electrodes 10 (bd) provided at the diagonal portions on the left oblique side are ground terminals GND1 and GND2 for grounding the metal cover 6. The arrangement of these electrodes of the surface mount resonator 1 has been customary as an established fact, and has been a so-called ready-made standard. [0005] The mounting substrate 2 is formed of a laminated ceramic substrate, and accommodates an IC chip 11 and a capacitor 12 constituting an oscillation circuit in a concave portion. On the obstructed surface side,
It has a connection electrode 13 (abcd) connected to the terminal electrode 10 (abcd) of the surface mount resonator 1. Then, the surface mount oscillator 1 and the mounting substrate 2 are joined and integrated by solder (not shown) or the like to form a surface mount oscillator. The crystal terminals X1 and X2 of the surface mount resonator 1
Is connected (input) to the IC chip 12 by a circuit pattern (not shown). Then, from the IC chip 12, the mounting electrodes 14 (abc
d) is extended. Normally, it is formed as a voltage input terminal (VC) for frequency control, a ground terminal (GND), an output terminal (OUT), and a power supply terminal (DC) clockwise with reference to the lower left corner in the figure. The arrangement of these electrodes as a surface mount oscillator has also been customary as an established fact, as described above, and has become a ready-made standard. In such a device, since the mounting substrate 2 may be joined to the ready-made surface mount resonator 1, it is necessary to newly develop, for example, a ceramic base which integrally accommodates the IC chip 11 and the crystal blank 1. There is no. In addition, the surface mount vibrator 1
Since only the non-defective products need to be selected and joined, the defective rate in the final product can be reduced. Further, the bottom surface of the surface mount resonator 1 and the mounting substrate 2
Are joined with their closed surfaces facing each other. Therefore, the area of the connection electrode 13 (abcd) of the mounting substrate 2 facing the terminal electrode 11 (abcd) of the surface mount resonator 1 is made sufficient. In addition, an insulating adhesive can be applied to the facing surface to increase the bonding strength. For example, when the opening side of the mounting substrate 2 is opposed to the bottom surface of the surface mount vibrator 1, only the upper surface of the outer peripheral frame of the mounting substrate 2 becomes the bonding surface. Therefore, as the miniaturization progresses, the area of the connection electrode 13 (abcd) decreases,
Decrease bonding strength. (Problems to be Solved by the Applicant) However, in the surface-mounted oscillator having the above configuration, the electrode arrangement uses the surface-mounted vibrator 1 of a ready-made standard. Either X1 or X2 overlaps with the output terminal 14c (OUT) as a surface mount oscillator. Therefore, in this case, there is a problem that the output from the surface-mounted oscillator interferes with the oscillation frequency of the crystal oscillator, causing, for example, phase modulation or phase noise, which adversely affects the oscillation characteristics. (Object of the Invention) It is an object of the present invention to provide a surface mount oscillator having improved oscillation characteristics. The basic solution of the present invention is that a pair of crystal terminals of a surface mount resonator and an output electrode terminal on a mounting board are not overlapped. In the present invention, since the crystal terminal and the electrode terminal for output are not overlapped, interference of the oscillation output with the crystal oscillator is prevented. Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a diagram of a surface mount oscillator for explaining an embodiment of the present invention. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified. Surface mounted oscillators
As described above, the surface mount resonator 1 in which the crystal piece 4 is hermetically sealed in the ceramic base 3 and the cover 6 and the IC chip 11 and the capacitor 12 are accommodated in the concave portions and the closed surface is bonded to the bottom surface of the surface mount resonator 1. And the mounting substrate 2. In this embodiment, the mounting electrodes 1 on the mounting substrate 2
4 (abcd) is a clock input terminal (V
C), ground terminal, output terminal (OUT) and power terminal (DC)
And Then, the terminal electrode 10 (ab
cd) counterclockwise with crystal terminals X1, X2, ground terminal GN
D2 and GND1. In short, the crystal terminals X1 and X2 are arranged on one end (the left side in the figure), and the ground terminals GND1 and GND2 are arranged on the other end (the same right). Note that these terminal electrodes 10 (ab
cd) is derived only by partially changing the wiring pattern of the laminated ceramic base 3. In this way, the crystal terminals X1 and X2 of the surface mount resonator 1 are connected to the voltage input terminals 14a (VC) of the mounting board 2.
And the power supply terminal 14d (DC). The ground terminals 10c (GND2) and 10b (GND1) of the surface mount
Ground terminal 14b (GND) and output terminal 1 of mounting substrate 2
4c (OUT). Therefore, the crystal terminals X1, X
2 and the output terminal 14c (OUT) do not overlap. From this, since the oscillation output of the surface mount oscillator does not interfere with the oscillation of the crystal oscillator, the generation of phase modulation, phase noise, etc. is suppressed, and the oscillation characteristics are favorably maintained. The power supply terminal 14d (DC) which overlaps the crystal terminals X1 and X2
Is a direct current and can be ignored. Further, the voltage input terminal 14a (VC) for frequency control has a completely low frequency, and has very little influence on the vibration of the crystal resonator. In the above embodiment, the crystal terminals X1 and X2 of the surface mount resonator 1 are overlapped with the voltage input terminal 14a (VC) and the power supply terminal 14d (DC) of the mounting board 2. It may be configured as shown in FIG. That is, while the mounting electrode 14 (abcd) of the mounting substrate 2 is kept as it is, the terminal electrode 10 (abcd) of the surface mounting vibrator 1 is turned clockwise in the ground terminal (GND1), the crystal terminal X1, the ground terminal (GND2) and the crystal terminal. X2. In this way, the crystal terminals X1 and X2 of the surface mount resonator 1 are connected to the power supply terminals 14d (D
C) and the ground terminal 14b (GND), so that the oscillation of the crystal unit is not affected at all, and the oscillation characteristics are further improved. Further, in the above embodiment, the bottom surface of the surface mount resonator 1 and the closed surface of the mounting substrate 2 are joined to face each other.
For example, as shown in FIG. 3, the opening side of the mounting substrate 2 may be opposed. Further, the mounting substrate 2 is only a frame, and circuit elements such as the IC chip 11 and the capacitor 12 may be fixed to the back surface of the surface mounting resonator 1 on which a circuit pattern (not shown) is formed (FIG. 4). ). Note that the reference numerals in the respective drawings are the same as those in FIG. 1 and their description is omitted. Although the plane area of the mounting substrate 2 is larger than that of the surface mounting vibrator 1, the dimensions may be the same. In addition, the crystal piece 4 held at one end is hermetically sealed in the ceramic base 3 by seam welding, but the holding form such as holding at both ends and the structure of the surface mounted oscillator 1 such as glass sealing are not limited. Basically, it can take any form. In short, according to the present invention, the terminal electrode 10 (abcd) of the existing surface mount resonator 1 is changed, and the output of the mounting substrate 2 having the crystal terminals X1 and X2 and the mounting terminal 14 (abcd) of the ready-made standard is changed. The terminal 14C (OUT) is not overlapped, and the purpose is to prevent mutual interference between the oscillation output and the vibration of the crystal unit. Belonging to the target range. According to the present invention, the pair of crystal terminals of the surface mount resonator and the output electrode terminals on the mounting board are not overlapped, so that a surface mount oscillator having good oscillation characteristics can be provided. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic exploded view of a surface mount oscillator for explaining an embodiment of the present invention. FIG. 2 is a schematic exploded view of a surface-mounted oscillator illustrating another embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a surface-mount oscillator illustrating another embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a surface-mount oscillator illustrating another embodiment of the present invention. FIG. 5 is a schematic sectional view of a surface mount oscillator according to the present applicant. FIG. 6 is an exploded view of a surface mount oscillator according to the present applicant. FIG. 7 is a diagram of a crystal blank applied to the surface mount oscillator according to the present applicant. [Description of Signs] 1 surface mount oscillator, 2 mounting board, 3 ceramic base, 4 crystal pieces, 5 metal ring, 6 metal cover, 7
Excitation electrode, 8 extraction electrode, 9 conductive adhesive, 10 terminal electrode, 11 IC chip, 12 capacitor, 13
Connection electrode, 14 mounting electrode.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03B 5/32 H03H 9/02 H03H 9/19

Claims (1)

(57) [Claims 1] An outer periphery of a crystal piece extending from a pair of extraction electrodes is electrically and mechanically held to hermetically seal the crystal piece in a rectangular container. A crystal oscillator having terminal electrodes including a pair of crystal terminals connected to the extraction electrode at four corners of the back surface of the container, and a surface joined to the bottom surface of the crystal oscillator and accommodating an integrated element in a frame. In a surface-mounted crystal oscillator having a surface-mounted substrate having mounting terminals including power, output and ground terminals at four corners on the surface side, the pair of crystal terminals and the mounting terminal for output are not overlapped. Characteristic surface mount crystal oscillator.