JP2007067967A - Temperature compensated crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature compensated crystal oscillator in which an initial frequency drift caused by heat generation after power supply is reduced. <P>SOLUTION: In the temperature compensated crystal oscillator having a substrate where a semiconductor component provided with a temperature sensor circuit, an oscillation stage circuit and an output buffer circuit inside is loaded and the semiconductor component is connected through a connection terminal, the temperature sensor circuit and a heat generation circuit in the semiconductor component are arranged at diagonal corners or the same side corners of the semiconductor component. Also, a pattern surrounding the temperature sensor circuit and the heat generation circuit is formed on the substrate where the semiconductor component is loaded, the pattern is wider than the width of the other wiring pattern on the substrate, the pattern is composed of aluminum, and the temperature sensor circuit and the heat generation circuit inside the semiconductor component are arranged on the outer side of a region surrounded by the connection terminal of the semiconductor component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

          The present invention relates to a temperature compensated crystal oscillator that reduces initial frequency drift due to heat generation after power is turned on.

          As a recent trend, extremely rapid development has been seen in items such as miniaturization, low profile, light weight, and low price of equipment mainly in the field of mobile communication such as wireless communication equipment and mobile phones. For this reason, it is necessary to realize a temperature-compensated crystal oscillator that meets these requirements, such as downsizing, low profile, and low price.

          Conventionally, as shown in FIG. 6, a single-plate substrate is subjected to multilayer printing, and a semiconductor component such as a capacitor, a resistor, and an integrated circuit constituting an oscillation circuit is mounted on a substrate on which a conductive pattern is further arranged. Starting with a temperature-compensated crystal oscillator having a structure in which a crystal unit is mounted and hermetically sealed in the same space, a printed circuit pattern for an oscillation circuit is arranged on the multilayer substrate as shown in FIG. A temperature-compensated crystal oscillator having a structure in which a container on which a semiconductor component is placed and another container on which a crystal resonator is mounted and hermetically sealed are stacked, or in recent years, a sealed structure as shown in FIG. There are many temperature-compensated crystal oscillators in the market that have a structure in which a crystal resonator and a semiconductor component such as an integrated circuit are mounted in a container with a concave opening and a container with a concave opening. It is.

          The crystal oscillator constituting the temperature-compensated crystal oscillator has a temperature characteristic in which the frequency changes depending on the environmental temperature. As an example, an AT-cut crystal oscillator mounted on the temperature-compensated crystal oscillator has a center frequency of It is known that the temperature with the smallest fluctuation is set to around 25 ° C., and the temperature characteristic peculiar to an AT-cut crystal resonator in which the frequency fluctuation becomes large on the high temperature side and the low temperature side.

          The land pattern applied to the outer surface of the temperature-compensated crystal oscillator is roughly divided into terminals used when manufacturing the temperature-compensated crystal oscillator, and customer mounting after the temperature-compensated crystal oscillator is shipped. There are two types of terminals used on the board. The terminals used at the time of manufacture include a memory access terminal and an inspection terminal. On the customer mounting board, terminals used by the customer include a control voltage terminal (Vdd) and a power supply terminal (Vc). ), A ground terminal (GND), and an output terminal (Output). Also, the terminals used only during the former manufacturing are those provided on the outer surface of the temperature-compensated crystal oscillator housing, and the latter terminals are used for the temperature-compensated crystal oscillator on the same surface as the mounting land. Some are provided on the outer bottom surface of the housing. On the other hand, the land pattern applied inside the casing of the temperature-compensated crystal oscillator includes a temperature sensor circuit section, an oscillation stage circuit section that forms one circuit block as a heating circuit section, and an output buffer circuit section inside. There is a connection terminal that is used when mounting a semiconductor component having a semiconductor component on a substrate inside a casing of a temperature-compensated crystal oscillator.

On the other hand, in recent wireless communication devices and mobile phones, the frequency drift (in the order of several tens of 10 ⁻⁹ ) of the temperature compensated crystal oscillator after power-on may be a problem. A temperature-compensated crystal oscillator used for a cellular phone usually has a low current consumption, and the current consumption is often about 1 mA. When the power is turned on, the IC chip, which is a semiconductor component mounted inside the temperature compensated crystal oscillator, starts to generate heat, and the temperature sensor voltage in the IC chip drifts. For example, the drift amount of the temperature sensor voltage is approximately 0.2 ° C. in terms of temperature.

          In addition, the applicant has not found prior art documents related to the present invention by the time of filing of the present application.

          However, since the structure of the temperature-compensated crystal oscillator is as shown in FIG. 8 described above, the heat generated by the IC chip, which is a semiconductor component, is thermally conducted to the crystal oscillator, and the crystal oscillator and IC It takes time for the temperature of the chip to be the same, and during this time, the temperature compensation circuit section in the IC chip and the temperature of the crystal unit are in a state of deviation, and the amount of this deviation is As shown in FIG. 9, there is a problem that it appears as a frequency drift immediately after the power is turned on.

          The present invention has been made under the technical background as described above. Accordingly, an object of the present invention is to provide a temperature compensated crystal oscillator in which the initial frequency drift due to heat generation after power-on is reduced.

          In order to solve these problems, the present invention provides a substrate on which a semiconductor component having a temperature sensor circuit portion, an oscillation stage circuit portion, and an output buffer circuit portion is mounted, and the semiconductor components are connected via connection terminals. In the temperature-compensated crystal oscillator having the temperature sensor circuit unit, the oscillation stage circuit unit, and the output buffer circuit unit inside the semiconductor component are located at the corner on the diagonal line of the previous semiconductor component or the corner on the same side. It is arranged.

          In addition, a pattern surrounding the temperature sensor circuit portion, the oscillation stage circuit portion, and the output buffer circuit portion is formed on the substrate on which the semiconductor component is mounted.

          The pattern is wider than the wiring pattern width on another substrate, and the pattern is made of aluminum.

          The temperature sensor circuit portion, the oscillation stage circuit portion, and the output buffer circuit portion inside the semiconductor component are arranged outside the region surrounded by the connection terminals of the semiconductor component.

          According to the temperature-compensated crystal oscillator of the present invention, the temperature-compensated crystal oscillator is configured by separating the oscillation stage circuit unit, which is a circuit unit that generates heat in the IC chip, and the output buffer circuit unit and the temperature sensor circuit unit from each other. The temperature drift due to heat generation can be significantly reduced.

          In addition, according to the temperature compensated crystal oscillator of the present invention, a pattern made of aluminum having a high heat dissipation effect, an oscillation stage circuit unit that is a circuit unit that generates heat inside a semiconductor component, an output buffer circuit unit, and a temperature sensor The temperature drift due to heat generation of the temperature compensated crystal oscillator can be remarkably reduced by effectively wiring on the substrate on which the semiconductor component is mounted so that the circuit portion is subjected to guard ring processing.

          Further, according to the temperature compensated crystal oscillator of the present invention, the temperature sensor circuit portion inside the semiconductor component, the oscillation stage circuit portion that is the heat generating circuit portion, and the output buffer circuit portion are surrounded by the connection terminals of the previous semiconductor component. By disposing each outside of the region, heat is radiated from the connection terminal portion, and temperature drift due to heat generation can be remarkably reduced.

          Further, according to the temperature-compensated crystal oscillator of the present invention, by arranging the oscillation stage circuit unit, which is a heat generating circuit unit inside the semiconductor component, the output buffer circuit unit, and the temperature sensor circuit unit adjacent to each other, The temperature generated by the heat generated by the previous temperature-compensated crystal oscillator that gradually changes the output oscillation frequency by conducting heat to the temperature sensor within a very short period of time. Drift can be significantly reduced.

          Further, according to the temperature compensated crystal oscillator of the present invention, the temperature drift due to heat generation can be remarkably reduced, and at the same time, the frequency stability of the temperature compensated crystal oscillator including the temperature drift can be improved.

          Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol in each figure shall show the same object.

          FIG. 1 shows a temperature sensor circuit unit 1 inside a semiconductor component according to an embodiment of the present invention, an oscillation stage circuit unit 2 as a heat generating circuit unit, and an output buffer circuit unit 3 on a diagonal line of the semiconductor component 4 described above. It is the schematic diagram which looked at the board | substrate 6 in which the semiconductor component 4 which shows a mode that it has been arrange | positioned in the corner part 9 was seen from the semiconductor component 4 mounting surface side. An IC chip that is a semiconductor component 4 is formed by disposing a heat generating circuit portion including a temperature sensor circuit portion 1 and an oscillation stage circuit portion 2 having a particularly large amount of heat generation and an output buffer circuit portion 3 at a corner portion 9 on a diagonal line. The arrangement is designed to suppress internal heat conduction as much as possible. This is because the heat generating circuit unit is arranged by maximizing the distance between the temperature sensor circuit unit 1 and the heat generating circuit unit comprising the oscillation stage circuit unit 2 and the output buffer circuit unit 3 that generate a large amount of heat. While the heat generated in step 1 is thermally conducted to the temperature sensor circuit unit 1, heat is radiated from the IC chip itself, and the effect of reducing the heat conduction is obtained.

          FIG. 2 shows a temperature sensor circuit section 1 inside a semiconductor component 4 according to an embodiment of the present invention, an oscillation stage circuit section 2 that is a heating circuit section, and an output buffer circuit section 3 that are on the same side of the previous semiconductor component 4. It is the schematic diagram which looked at the board | substrate 6 in which the semiconductor component 4 which shows a mode that it has been arrange | positioned in the corner 10 of the side was seen from the semiconductor component 4 mounting surface side. By disposing the temperature sensor circuit unit 1 and the heat generating circuit unit 2 including the oscillation stage circuit unit 2 and the output buffer circuit unit 3 that generate a particularly large amount of heat at the corners 10 on the same side, the IC as the semiconductor component 4 can be obtained. In this arrangement, the heat conduction inside the chip is suppressed as much as possible. This is achieved by arranging the distance between the temperature sensor circuit unit 1 and the heat generating circuit unit comprising the oscillation stage circuit unit 2 and the output buffer circuit unit 3 that generate a large amount of heat, as compared with the first embodiment. Similarly, while the heat generated in the heat generating circuit portion is thermally conducted to the temperature sensor circuit portion 1, heat is radiated from the IC chip itself, thereby reducing the effect of heat conduction.

          FIG. 3 shows a temperature sensor circuit unit 1 inside the semiconductor component 4 mounted on the substrate 6 on which the semiconductor component 4 according to another embodiment of the present invention is mounted, and an oscillation stage circuit unit 2 which is a heat generating circuit unit. FIG. 2 is a schematic diagram showing a substrate 6 on which a semiconductor component 4 is mounted, as viewed from the semiconductor component 4 mounting surface side, showing a state in which a pattern 11 surrounding the output buffer circuit section 3 is formed. In order to suppress the heat conduction from the heat generating circuit part to the temperature sensor circuit part 1, the heat of each circuit part is cut off using a guard ring technique, and it is made of aluminum with high heat dissipation and others. An IC chip is mounted so that the wiring pattern wider than the wiring pattern width surrounds the temperature sensor circuit section 1 inside the semiconductor component 4, the oscillation stage circuit section 2 that is a heat generation circuit section, and the output buffer circuit section 3. By forming on the substrate 6, the heat dissipation is improved and the heat conducted to the temperature sensor circuit unit 1 is reduced, and the temperature drift due to heat generation is remarkably reduced.

          FIG. 4 shows a temperature sensor circuit portion 1 inside a semiconductor component 4 according to another embodiment of the present invention, an oscillation stage circuit portion 2 as a heat generating circuit portion, and an output buffer circuit portion 3 connected to a connection terminal 5 of the semiconductor component 4. Schematic view of the substrate 6 on which the semiconductor component 4 is mounted as viewed from the semiconductor component 4 mounting surface side, showing a state in which the semiconductor component 4 is disposed outside the region surrounded by, and at the corner 9 on the diagonal line of the previous semiconductor component 4 FIG. Normally, the IC pad is provided to connect the IC chip and the package, but the heat dissipation is enhanced by connecting to the circuit portion of the package. In the first embodiment and the second embodiment, the position of the IC pad is arranged along two or more sides of the semiconductor component 4. The IC pad blocks the temperature sensor circuit portion 1 and the heat generating circuit portion. In other words, the temperature sensor circuit unit 1 inside the semiconductor component 4, the oscillation stage circuit unit 2 that is a heat generating circuit unit, and the output buffer circuit unit 3 are surrounded by the connection terminals 5 of the semiconductor component 4. By disposing outside the region, the heat generated in the heat generating circuit unit is efficiently radiated, the heat conducted to the temperature sensor circuit unit 1 including the temperature sensor is reduced, and the temperature drift due to the heat generation is remarkably reduced. It plays.

          FIG. 5 shows a temperature sensor circuit portion 1 inside a semiconductor component 4 according to another embodiment of the present invention, an oscillation stage circuit portion 2 that is a heat generating circuit portion, and an output buffer circuit portion 3 that are connected to a connection terminal 5 of the semiconductor component 4. The substrate 6 on which the semiconductor component 4 is mounted is shown from the side of the semiconductor component 4 mounting surface, showing a state in which the semiconductor component 4 is disposed outside the region surrounded by and on the same side of the previous semiconductor component 4. It is a schematic diagram. The heat generated in the heat generation circuit unit is conducted to the temperature sensor and the temperature sensor circuit unit 1 within a very short time, so that the output oscillation frequency is gradually increased. This has the effect of significantly reducing temperature drift due to heat generation such as change.

          FIG. 6 shows a conventional single plate substrate that is subjected to multilayer printing, and a semiconductor component 4 such as a capacitor, a resistor, and an integrated circuit constituting an oscillation circuit is mounted on the substrate on which a conductive pattern is further arranged. 1 is a schematic side cross-sectional view of a temperature compensated crystal oscillator 7 having a structure in which a quartz resonator is mounted and hermetically sealed, as viewed from the side.

          FIG. 7 shows a temperature compensated crystal oscillator 7 having a structure in which a conventional container on which a semiconductor component 4 is placed on a multilayer substrate and another container hermetically sealed with a crystal resonator mounted thereon are stacked. FIG. In the temperature compensated crystal oscillator 7 having the configuration shown in FIG. 7, the heat generated by the IC chip as the semiconductor component 4 is conducted to the crystal resonator, and the temperature of the crystal resonator and the IC chip is the same. It takes time to become, and during this time, the temperature compensation circuit portion in the IC chip and the temperature of the crystal resonator are in a state of deviation, and the amount of this deviation is shown in FIG. Thus, there is a problem that it appears as a frequency drift immediately after power-on.

          FIG. 8 shows a temperature-compensated crystal oscillator having a different structure in which a crystal resonator and a semiconductor component 4 such as an integrated circuit are mounted on a conventional container having a sealed structure and a container having a concave opening. FIG. 7 is a schematic side sectional view of 7 viewed from the side surface direction.

          FIG. 9 shows an IC, which is a semiconductor component mounted in the temperature-compensated crystal oscillator 7 after turning on the power, which appears in the conventional temperature-compensated crystal oscillator 7 as shown in FIG. 6, FIG. 7, and FIG. FIG. 6 is a schematic characteristic diagram showing a state in which heat generation of the chip starts, the temperature sensor voltage in the IC chip drifts, and as a result, the oscillation frequency drifts.

          The case of the temperature compensated crystal oscillator 7 of the present invention may be made of a material other than ceramic, such as a low-temperature fired ceramic multilayer substrate, and such a case is also included in the technical scope of the present invention. Needless to say.

The temperature sensor circuit portion inside the semiconductor component which is an embodiment of the present invention, the oscillation stage circuit portion which is a heat generating circuit portion, and the output buffer circuit portion are arranged at the diagonal corners of the previous semiconductor component. It is the schematic diagram which looked at the board | substrate with which the semiconductor component which shows a mode is mounted from the semiconductor component mounting surface side. The temperature sensor circuit portion inside the semiconductor component which is an embodiment of the present invention, the oscillation stage circuit portion which is a heat generating circuit portion, and the output buffer circuit portion are arranged at corners on the same side of the previous semiconductor component. It is the schematic diagram which looked at the board | substrate with which the semiconductor component which shows a mode to be mounted was seen from the semiconductor component mounting surface side. On a substrate on which a semiconductor component according to another embodiment of the present invention is mounted, a temperature sensor circuit section inside the mounted semiconductor component, an oscillation stage circuit section that is a heat generating circuit section, and an output buffer circuit section are enclosed. It is the schematic diagram which looked at the board | substrate with which a semiconductor component is mounted which shows a mode that such a pattern is formed from the semiconductor component mounting surface side. The temperature sensor circuit part inside the semiconductor component which is another embodiment of the present invention, the oscillation stage circuit part which is a heat generating circuit part, and the output buffer circuit part are outside the region surrounded by the connection terminals of the semiconductor component, FIG. 3 is a schematic diagram showing a substrate on which a semiconductor component is mounted, as viewed from the semiconductor component mounting surface side, showing a state where the semiconductor component is disposed at a corner on a diagonal line of the previous semiconductor component. The temperature sensor circuit part inside the semiconductor component which is another embodiment of the present invention, the oscillation stage circuit part which is a heat generating circuit part, and the output buffer circuit part are outside the region surrounded by the connection terminals of the semiconductor component, FIG. 3 is a schematic diagram showing a substrate on which a semiconductor component is mounted as viewed from the semiconductor component mounting surface side, showing a state in which the semiconductor component is disposed adjacent to each other on the same side of the previous semiconductor component. Semiconductor components such as capacitors, resistors, and integrated circuits that constitute an oscillation circuit are mounted on a substrate on which a conventional single plate substrate is subjected to multi-layer printing and a conductive pattern is further disposed, and a crystal resonator is placed in the same space. FIG. 2 is a schematic side cross-sectional view of a temperature compensated crystal oscillator having an airtightly sealed configuration mounted from the side. A temperature compensated type with a printed circuit pattern for an oscillation circuit placed on a conventional multilayer substrate, a container in which a semiconductor component is placed on the multilayer substrate, and another container hermetically sealed with a crystal resonator mounted 1 is a schematic side cross-sectional view of a crystal oscillator as viewed from the side. Schematic view of a temperature compensated crystal oscillator with a structure composed of a conventional container with a sealed structure and a container with a concave opening mounted with a crystal resonator and semiconductor components such as an integrated circuit, as seen from the side. FIG. Heat generation of the IC chip, which is a semiconductor component mounted in the temperature compensated crystal oscillator after turning on the power, appears in the conventional temperature compensated crystal oscillator, and the temperature sensor voltage in the IC chip drifts. It is a rough characteristic figure which shows a mode that an oscillation frequency drifts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature sensor circuit part 2 Oscillation stage circuit part 3 Output buffer circuit part 4 Semiconductor component 5 Connection terminal 6 Substrate 7 Temperature compensation type crystal oscillator 9 Diagonal corner,
10 Corners on the same side 11 Pattern 12 Wiring pattern width 13 Outside the area surrounded by the connection terminals

Claims (4)

In a temperature compensated crystal oscillator including a temperature sensor circuit unit, a semiconductor component having an oscillation stage circuit unit, and an output buffer circuit unit therein, and a substrate to which the semiconductor component is connected via a connection terminal.
A temperature characterized in that the temperature sensor circuit part, the oscillation stage circuit part, and the output buffer circuit part inside the semiconductor component are arranged at a corner on the diagonal line of the semiconductor component or at a corner on the same side. Compensated crystal oscillator.           2. A pattern surrounding the temperature sensor circuit portion, the oscillation stage circuit portion, and the output buffer circuit portion is formed on the substrate on which the semiconductor component is mounted. The temperature compensated crystal oscillator described.           3. The temperature compensated crystal oscillator according to claim 1, wherein the pattern is wider than the wiring pattern width on the other substrate, and the pattern is made of aluminum.           The temperature sensor circuit portion, the oscillation stage circuit portion, and the output buffer circuit portion inside the semiconductor component are arranged outside a region surrounded by the connection terminals of the semiconductor component. The temperature-compensated crystal oscillator according to claim 1, claim 2, or claim 3.

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