JP2597381Y2 - Temperature compensated crystal oscillator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature-compensated crystal oscillator, and more particularly to a small, low-profile temperature-compensated crystal oscillator.

[0002]

2. Description of the Related Art As shown in FIG. 3, a typical circuit of a temperature-compensated crystal oscillator includes a crystal resonator element that performs thickness-shear vibration, capacitors C ₁ and C ₂ , a variable resistor and a variable resistor. a frequency adjustment circuit W consisting of trimer components 8 such as a capacitor, a thermistor 5, 5 ', a capacitor C _3,
A temperature compensation circuit X composed of C ₄ , resistors R ₅ and R ₆ , an oscillation circuit Z mainly composed of an oscillation transistor Tr ₂ ,
Consisted of the amplifying transistor Tr ₁ and mainly comprises an amplifier circuit Y.

Conventionally, a temperature-compensated crystal oscillator 40 having such a circuit is, as shown in FIG. 4, a crystal resonator in which a crystal resonator element is sealed on an insulating substrate 41 on which a wiring pattern is formed. After arranging elements 43 such as a transistor, a capacitor, a resistor, and a samister necessary for the above-described circuit configuration including the element 42, the whole was covered with a cap body 44.

[0004] At present, it is often used to integrate transistors, small capacitors, resistors, and the like into one IC chip to reduce the overall shape.

[0005] The reason for such a structure is that a crystal oscillator piece is arranged on a circuit board together with other electronic parts, and the entire circuit board is constituted by a crystal oscillator covered with a cap that can be hermetically sealed. However, in general, a baking (120 ° C.) step is required to improve the aging characteristics of the quartz oscillator piece after the quartz oscillator piece is hermetically sealed with a cap or the like. When the baking step is performed, organic gas and moisture such as resin components are filled in the cap from the resin mold portion of the IC chip, and a variation of the oscillation frequency of ± 5 ppm or more occurs over time. That's why.

In such a configuration, a crystal oscillator (actually, a stem, a can case, and a lead terminal) 42 arranged on a substrate 41 is arranged and further covered with a cap body 44. It has been difficult to achieve a low-profile temperature-compensated crystal oscillator of, for example, 4 mm or less due to the thickness of the crystal oscillator.

The present invention has been devised in view of the above-mentioned problems, and has a small substrate area and a low profile, and furthermore, has a temperature at which the oscillation frequency of the crystal unit has a very small fluctuation. An object of the present invention is to provide a compensated crystal oscillator.

[0008]

According to the present invention, according to the present invention, a temperature-compensated crystal in which a crystal resonator element, a frequency adjustment circuit, a temperature compensation circuit, an oscillation circuit, and an amplifier circuit are arranged on a multilayer circuit board. An oscillator, wherein the crystal resonator element and the predetermined circuit are connected to the multilayer circuit board via internal conductors, and only the crystal element is covered with a cap on the multilayer circuit board. That is, hermetically sealed.

[0009]

According to the present invention, an IC chip integrated in a crystal resonator element, a frequency adjustment circuit, a temperature compensation circuit, an oscillation circuit, and an amplification circuit, and a variable resistance component that cannot be integrated are provided on a circuit board. Only the electronic elements such as the power supply and the thermistor are arranged. Thereby, the area of the substrate can be made extremely small.

In addition, since a cap for hermetically sealing only the crystal oscillator piece is attached, unnecessary gas does not accumulate in the cap even if the crystal oscillator piece is heat-treated in a baking process. The oscillation frequency characteristics of the child piece can be stabilized for a long time. In addition, since the thickness of the entire oscillator is limited only by the thickness of the circuit board and the thickness of the cap that seals the crystal resonator piece, an extremely low-profile temperature-compensated crystal oscillator is achieved. .
Further, since the connection between the crystal resonator element and the IC chip or other electronic element is connected via the internal conductor of the multilayer circuit board, the crystal resonator element including the cap body and the multilayer circuit board is stored. The airtightness of the space can be maintained with very high reliability, so that the oscillation frequency characteristics of the crystal unit can be stabilized for a long time.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a temperature-compensated crystal oscillator according to the present invention. FIG. 1 is a plan view of the temperature-compensated crystal oscillator of the present invention, in which an upper surface of a cap for sealing a crystal resonator element is omitted. FIG. 2 is a sectional view thereof.

In FIG. 1, a temperature-compensated crystal oscillator is integrated on a multilayer circuit board 1 in a crystal resonator element 2, a frequency adjustment circuit W, a temperature compensation circuit X, an amplifier circuit Y and an oscillation circuit Z. IC chip 6, resistance network element 7 that cannot be integrated, variable electronic components such as variable resistors, 8
And thermistors 5, 5 'and a decoupling capacitor 9 are arranged.

The multilayer circuit board 1 is made of alumina ceramic or the like, and has a conductor 16 having a predetermined wiring pattern formed therein. A wiring pad (not shown) is formed. Terminals 11 to 14 formed by conductive through holes are formed at the ends of the substrate 1, respectively.
Each terminal 11 to 14 is connected to the internal conductor 16. Specifically, holes serving as via holes and through holes are formed in an alumina green sheet, and a predetermined wiring pattern serving as the conductor 16 is printed on the green sheet using a conductive paste.

At this time, a conductor paste is applied to the end surfaces of the through holes, and the via holes are filled with a conductor base. By laminating a plurality of such green sheets,
A laminate having the internal conductor 16 and the wiring pads formed on the surface is obtained. Subsequently, the green sheet is sintered to cause a sintering reaction, and each conductor 16 is baked on a substrate.

The crystal resonator element 2 has resonator electrodes formed on both main surfaces of the crystal element in the thickness-shear mode. Note that the crystal resonator element 2 is cut into a roughly oval shape in order to reduce the size. This crystal resonator element 2 is connected to a pad (not shown) communicating with the internal conductor 16 of the multilayer circuit board 1.
It is connected to the supports 3, 3 'via a conductive adhesive. Further, the quartz-crystal vibrating piece 2 is hermetically sealed with a cap 4 made of ceramic, metal or the like, which is hollow and has a substantially rectangular parallelepiped shape.

On the outside of the cap body 4 of the multilayer circuit board 1, an IC chip 6 connected to a pad (not shown) communicating with the internal conductor 16 of the multilayer circuit board 1 and the resistance network element 7 cannot be integrated. variable resistor 8, a thermistor 5, 5 ', decoupling capacitor 9 (C ₉₎ are joined by soldering or the like.

The IC chip 6 integrates a portion shown by a dotted line of the temperature-compensated crystal oscillation circuit shown in FIG.
The capacitors C ₁ and C _{2 of the} frequency adjustment circuit W, the capacitors C ₃ and C _{4 of the} temperature compensation circuit X, the amplifying transistor Tr ₁ of the amplifier circuit Y, the capacitor C ₇ , and the resistors R ₁ , R ₂ , R
₄ , an oscillation transistor Tr ₂ of the oscillation circuit Z, a capacitor C ₅ , and a C ₆ resistor R ₃ are integrated. The IC chip 6 is bonded to predetermined wiring pads by face bonding, wire bonding, or the like, and is further potted with a silicone resin or the like from above. Each of the integrated capacitors has a capacity of several tens of pico-F, and can be easily integrated. .

The resistance network element 7 includes resistance elements R ₅ and R ₆ constituting the temperature compensation circuit W. This is because the low-temperature region (−30 ° C. to 25 ° C.) and the high-temperature region (25 ° C.
℃ ~ 80 ℃) to perform temperature compensation, but actually,
Since it is necessary to finely adjust the resistance values of the resistance elements R ₅ and R ₆ , it is desirable not to integrate them. That is, fine adjustment can be performed by laser trimming the resistor film of the resistor network element 7.

In the drawing, reference numeral 10 denotes a support 3 of the quartz oscillator piece 2.
This is a terminal for checking the characteristics of the crystal resonator element 2 connected to the terminal. The terminals 10, 10 are electrically connected to the support 3 through the internal conductor 16 of the multilayer circuit board 1.

As a result, since no wiring pattern is formed on the surface where the cap body 4 and the multilayer circuit board 1 are in contact with each other, the cap body 4 and the multilayer circuit board 1 come into direct contact with each other, so that sealing is performed. Even when the members are joined via the material 15, extremely stable hermetic sealing can be achieved. If the cap body 4 is made of ceramic, a glass sealing material 15 is used. If the cap body 4 is made of metal, a metal film is formed on a portion of the multilayer circuit board 1 in contact with the cap body 4, and the multilayer circuit board 1 is made of a brazing material.
And the cap body 4 are joined.

In the figure, 11, 12, 13, and 14 are:
This is a terminal of an end face through hole in which a conductor film formed over the end face of the multilayer circuit board 1 is formed. Terminal 11 is a control terminal of the oscillation circuit, terminal 12 is a ground terminal,
Terminal 13 is an oscillation output terminal, and 14 is a drive power supply terminal.

The temperature-compensated crystal oscillator having such a configuration is constituted by the temperature-compensated crystal oscillation circuit shown in FIG.
Here, to explain the circuit, the frequency adjustment circuit W is composed of capacitors C ₁ and C ₂ and a variable resistor 8,
It is connected between the crystal blank 2 and the ground, and adjusts the oscillation frequency of the crystal resonator blank 2 at normal temperature.

The temperature compensating and adjusting circuit X includes a Samister 5,
5 ', is a capacitor C _3, C _4, and resistors R _5, R _6, Samisuta 5 performs change of the compensation of the frequency-temperature characteristic at the high temperature region by the capacitor C _4, the resistor R _5, also Samisuta 5 , Capacitor C ₃ , and resistor R ₆
Thus, a change in the frequency temperature characteristic in the low temperature region is compensated.

The oscillation circuit Z includes an oscillation transistor Tr ₂
Primarily consists amplifier circuit Y are mainly mainly composed of the amplifying transistor Tr _1.

[0025] That is, the base of the oscillation transistor Tr _2, the oscillating signal from the crystal oscillator piece 2 is supplied, emitting mutabilis signal outputted from the collector of the transistor Tr ₂ is the emitter of the amplifying transistor Tr ₁ Is input to Input signal of the amplification transistor Tr ₁ is amplified here is output from the collector of the amplifying transistor Tr _1. This output signal is a DC component is cut through the capacitor C _7, a predetermined level oscillation output. still,
The capacitors C ₅ and C ₆ are oscillation capacitors for forming a Colpitts type oscillation circuit.

In the temperature-compensated crystal oscillator having the above-described configuration, the multilayer circuit board 1 may be a circuit board having about two to three layers, and can be formed with a thickness of about 0.6 mm. Also, the height of the support 3 of the crystal resonator element 2 may be such that a gap is formed between the support 1 and the substrate 1 to such an extent that the crystal resonator element can be vibrated, and the height can be about 0.3 mm. Further, the thickness of the quartz oscillator piece 2 is about 0.1 to 0.15 mm, and the thickness of the conductive adhesive material required for bonding the support 3 and the quartz oscillator piece 2 is 0.2 to 0.3 mm. For this reason, it is sufficient that the height of the hollow portion of the cap body 4 is about 0.85 mm.
2 mm. In other words, the thickness of the substrate 1 is 0.6 mm and the thickness of the cap body 4 is 1.2 mm.
mm, and an unprecedented low-profile temperature-compensated crystal oscillator is achieved.

Further, the quartz oscillator piece 2 is provided in the cap body 4.
Only the cap member 4 is disposed even if heat treatment is performed in a baking step to improve aging characteristics.
Unnecessary gas is not generated inside, so that the frequency temperature characteristic does not fluctuate greatly over a long period of time. With the temperature compensated crystal oscillator of the present invention, even a long-term change over time is 2-3.
The fluctuation can be suppressed to about ppm.

Further, a multilayer circuit board 1 is used as a circuit board, and each of the conductors 16 connecting the quartz oscillator piece 2 to the frequency adjustment circuit W, the temperature compensation circuit X, the oscillation circuit Z, and the amplification circuit Y.
Can be formed inside the multilayer circuit board 1,
Since the circuit occupation area of the multilayer circuit board 1 can be integrated, a small temperature-compensated crystal oscillator can be obtained.

Further, since a wiring pattern for connecting the quartz oscillator piece 2 and each circuit is not formed on the substrate contacting surface of the cap body 4 attached to the multilayer circuit board 1, the wiring pattern is not used for solder sealing. It is not necessary to form a conductor film for sealing by insulating the pattern, and even in the case of performing glass sealing, sealing can be performed with high airtightness. As a result, sealing of the cap body 4 is extremely reliable. Become.

[0030]

According to the present invention, the oscillation frequency of the crystal resonator is stabilized because the crystal resonator piece is attached with the cap body capable of hermetically sealing only the crystal resonator piece.

Further, by forming the conductors for attaching the cap body and connecting the respective circuits on the circuit board, a small-sized, low-profile temperature-compensated crystal oscillator is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a temperature-compensated crystal oscillator according to the present invention.

FIG. 2 is a cross-sectional view of the temperature-compensated crystal oscillator according to the present invention.

FIG. 3 is a circuit diagram showing a typical temperature-compensated crystal oscillation circuit.

FIG. 4 is a cross-sectional view of a conventional temperature-compensated crystal oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer circuit board 2 ... Crystal oscillator piece 3 ... Support body 4 ... Cap body W ... Frequency adjustment circuit X ... Temperature compensation circuit Y ... Oscillation circuit Z ...・ Amplifier circuit

Claims (1)

(57) [Scope of request for utility model registration] 1. A temperature-compensated crystal oscillator in which a crystal resonator element , a frequency adjustment circuit, a temperature compensation circuit, an oscillation circuit, and an amplifier circuit are arranged on a multilayer circuit board , wherein the crystal element is used.
And the predetermined circuit on the multilayer circuit board via an internal conductor.
With connecting Te, the multilayer circuit temperature compensated crystal oscillator on a substrate Te only crystal oscillator piece and envelope in the cap member, characterized in that hermetically sealed.