JP2012156352A - Mounting structure of noise countermeasure electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of a noise countermeasure electronic component capable of significantly suppressing time and cost required for designing a circuit board.SOLUTION: A power feeding path for connecting a power supply terminal 1a of an IC1 to a power feeding circuit, in the case where a two-terminal type resistive element 7 is interposed between first wiring patterns 2a and 2b for power source line, is comprised of a first power feeding path which goes through the two-terminal type resistive element 7 and a second power feeding path that goes through a three-terminal capacitor 8. Here, the three-terminal capacitor 8 is used as a bypass capacitor, to lower the impedance of a power supply wiring, resulting in stable operation of the IC1. In the case where the two- terminal type resistive element 7 is not interposed between the first wiring pattern 2a and 2b for power supply line, the power feeding path only comprises the second power feeding path. In this case, the three-terminal capacitor 8 is used as a decoupling capacitor, for noise countermeasure having a large noise elimination effect.

Description

  The present invention relates to a mounting structure of a noise countermeasure electronic component on a circuit board having a power supply path for connecting a power supply terminal of a load to a power supply circuit.

  As electronic devices become more sophisticated and multifunctional, ICs (highly integrated circuits) such as CPUs (central processing units) are being driven at high speeds by low voltage and large current. For this reason, in a multilayer circuit board, circuit pattern design and noise countermeasures for low voltage / large current driving and stable operation are required. In order to meet these demands, conventionally, for example, a method of arranging a low ESL (residual inductance) decoupling capacitor around the IC for noise countermeasures, and for a stable operation of the IC, for example, a power supply using a bypass capacitor There are techniques for reducing the impedance of wiring.

  As a noise countermeasure technique using the former low ESL decoupling capacitor, there is conventionally a multilayer circuit board disclosed in, for example, Patent Document 1 as Embodiment 3. In this multilayer circuit board, the IC power supply pattern for the IC power supply terminal connected to the IC power supply terminal in any layer is spatially separated from the power supply pattern for the external power supply connected to the external power supply. Is provided. The IC power supply terminal power supply pattern and the external power supply power supply pattern are connected to each other through a through internal electrode between the input / output terminals of the three-terminal capacitor. Therefore, in order to reach the power pattern for the external power source from the IC power source terminal, it is necessary to pass through the through-terminal electrode of the three-terminal capacitor. For this reason, the three-terminal capacitor functions as a low ESL decoupling capacitor, and noise countermeasures against high-frequency current noise generated at the IC power supply terminal are effectively performed.

  In addition, as a technique for lowering impedance using the latter bypass capacitor, there is a conventional through capacitor mounting method disclosed in Patent Document 2, for example. In this mounting method, a short-circuit conductor that short-circuits both conductive terminals of the feedthrough capacitor is separately provided on the side surface of the feedthrough capacitor. Alternatively, a short circuit path for short-circuiting both conductive terminals of the feedthrough capacitor is provided on the surface of the substrate on which the feedthrough capacitor is mounted. The feedthrough capacitor is a three-terminal capacitor in which an internal electrode penetrates between both conductive terminals, and a short-circuit conductor or a short-circuit path that short-circuits both conductive terminals is configured such that the equivalent series resistance is smaller than that of the through-electrode. ing. Therefore, when the feedthrough capacitor mounted in this way is used as a bypass capacitor in the wiring pattern for the power supply line of the IC, the power supply wiring has a low impedance, and the stable operation of the IC is achieved.

JP 2003-297963 A JP-A-6-349678

  However, the conventional noise countermeasure technique disclosed in Patent Document 1 and the like and the low impedance technique disclosed in Patent Document 2 and the like performed using a three-terminal type noise filter such as a three-terminal capacitor are simultaneously realized. It is difficult. Accordingly, the three-terminal type noise is emphasized in either the usage mode as a decoupling capacitor as disclosed in Patent Document 1 or the like or the usage mode as a bypass capacitor as disclosed in Patent Document 2 or the like. It is necessary to design a circuit using a filter. In order to consider which usage mode to place emphasis on, in the conventional circuit board design stage, the effect of noise countermeasure design that puts emphasis on the usage mode as a decoupling capacitor and the usage mode as a bypass capacitor It was necessary to confirm by comparing the effect of the power supply wiring design with low impedance. For this reason, conventionally, at the design stage of the circuit board, it is necessary to produce a plurality of circuit boards based on these designs, and it takes a lot of time and cost to design the circuit board on which the noise countermeasure electronic component is mounted.

The present invention has been made to solve such problems,
A first power supply path for connecting a power supply terminal of a load to a power supply circuit, wherein a two-terminal resistance element or a two-terminal induction element is detachably inserted;
A circuit board includes a second power supply path connecting a power supply terminal to the power supply circuit in parallel with the first power supply path, in which a three-terminal noise filter having an input / output terminal and a ground terminal is interposed between the input / output terminals. In addition, a mounting structure for noise-reducing electronic components was constructed.

  According to this configuration, the power supply path that connects the power supply terminal of the load to the power supply circuit is the first power supply when a two-terminal resistance element or a two-terminal induction element is inserted in the first power supply path. It is configured by two paths, a path and a second power supply path. In this case, a two-terminal resistive element or a two-terminal inductive element and a three-terminal noise filter are inserted in parallel between the power supply terminal of the load and the power supply circuit, and between the input and output terminals of the three-terminal noise filter. A two-terminal resistive element or a two-terminal inductive element is connected in parallel. Therefore, the three-terminal type noise filter is used as a bypass capacitor, the impedance of the power supply wiring is lowered, and the stable operation of the load is achieved.

  On the other hand, the power supply path for connecting the power supply terminal of the load to the power supply circuit is a two-terminal resistance element or a two-terminal type when a two-terminal resistance element or a two-terminal induction element is not inserted in the first power supply path. The first power supply path is opened at the place where the inductive element is inserted, and is configured by a single path including only the second power supply path. In this case, only the three-terminal type noise filter is inserted between the power supply terminal of the load and the power supply circuit, and only the input / output terminals of the three-terminal type noise filter are interposed alone in the power supply path. Therefore, a three-terminal type noise filter is used as a decoupling capacitor, and a noise countermeasure with a large effect of removing high frequency noise generated at the power supply terminal can be achieved.

  Therefore, the usage mode of the 3-terminal type noise filter as the bypass capacitor and the usage mode as the decoupling capacitor can be easily switched by attaching / detaching the 2-terminal resistance element or the 2-terminal induction element to / from the first power supply path. It becomes possible. Therefore, it becomes possible to easily examine which usage mode should be emphasized and design a circuit board without producing a plurality of circuit boards as in the prior art. As a result, it is possible to provide a mounting structure for a noise countermeasure electronic component that can significantly reduce the time and cost required for designing a circuit board on which the noise countermeasure electronic component is mounted.

The present invention also provides:
The first power supply path is formed as a first power line pattern on the circuit board surface on which the load is mounted, and the two-terminal resistance element or the two-terminal induction element is mounted on the substrate surface adjacent to the load. And
The second power supply path is formed as a second power line wiring pattern on the back side of the circuit board, and the three-terminal noise filter is mounted on the back side of the board located behind the load mounting position. To do.

  According to this configuration, since the two-terminal resistance element or the two-terminal induction element is mounted on the substrate surface adjacent to the load, the physical distance between the load and the two-terminal resistance element or the two-terminal induction element The power supply path by the first power supply line wiring pattern from the power terminal of the load to the two-terminal resistive element or the two-terminal inductive element is shortened. In addition, since the three-terminal type noise filter is mounted on the back side of the substrate located behind the load mounting position, the physical distance between the load and the three-terminal type noise filter is shortened, and the three terminals from the power supply terminal of the load are reduced. The power supply path by the second power line wiring pattern reaching the input / output terminal of the type noise filter is shortened. For this reason, the wiring impedance formed by the power supply path between the power supply terminal and the two-terminal type resistive element or the two-terminal type inductive element, and the wiring formed by the power supply path between the power supply terminal and the three-terminal type noise filter The impedance is reduced, the impedance of the power supply wiring can be further reduced, and the noise removal effect by the three-terminal noise filter is further enhanced.

  In the present invention, the three-terminal type noise filter is a three-terminal capacitor.

  According to this configuration, since there is only a penetrating internal electrode having no resistance element or induction element between the input / output terminals of the three-terminal noise filter, the impedance between the input / output terminals of the three-terminal noise filter is reduced. For this reason, even with this configuration, the impedance of the power supply wiring can be further reduced, and the noise removal effect by the three-terminal noise filter is further enhanced.

  According to the present invention, as described above, there is provided a mounting structure for a noise countermeasure electronic component capable of significantly reducing the time and cost required for designing a circuit board on which the noise countermeasure electronic component is mounted.

It is sectional drawing which shows notionally the mounting structure of the noise countermeasure electronic component by one embodiment of this invention. It is a perspective view which shows the external appearance structure and internal structure of a 3-terminal capacitor | condenser in the mounting structure shown in FIG. It is a figure which shows the simulation model in case the 2 terminal type resistance element is inserted between the wiring patterns for 1st power supply lines in the mounting structure shown in FIG. It is a figure which shows the simulation model in case the 2 terminal type resistive element is not inserted between the wiring patterns for 1st power supply lines in the mounting structure shown in FIG. It is a graph which shows the result of having carried out the simulation analysis of the power supply impedance in each model shown in FIG. 3 and FIG. It is a graph which shows the result of having carried out the simulation analysis of the insertion loss by each model shown in FIG. 3 and FIG.

  Next, the mounting structure of the noise countermeasure electronic component according to the embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view conceptually showing a mounting structure according to an embodiment of these components when the noise countermeasure electronic component is a two-terminal resistance element and a three-terminal capacitor.

  A digital IC 1 having a terminal array of BGA (Ball Grid Array) type is mounted on the surface of the multilayer circuit board. In the multilayer circuit board, first power supply line wiring patterns 2a and 2b are formed on the first layer on the substrate surface, and a ground pattern layer 3 is formed on the second layer in the board. Further, second power supply line wiring patterns 4a and 4b and a ground wiring pattern 5 are formed in the third layer on the back surface of the substrate.

  The power supply terminal 1a of the IC 1 is connected to the first power supply line wiring pattern 2a, and is also connected to the second power supply line wiring through the IC via 6a and through the hole 3a formed in the ground pattern layer 3. It is connected to the pattern 4a. The ground terminal 1b of the IC 1 is connected to the ground pattern layer 3 via the IC via 6b without contacting the first power supply line wiring pattern 2a.

  Between the first power supply line wiring patterns 2a and 2b, a two-terminal resistance element 7 is detachably inserted by solder connection. For this reason, lands for solder connection are formed at the contact portions of the first power supply line wiring patterns 2a and 2b that are in contact with both terminals 7a and 7b of the two-terminal resistance element 7. The mounting position of the two-terminal resistance element 7 on the substrate surface is a position adjacent to the IC 1 as shown in FIG. In this embodiment, a short chip resistor of 0Ω is used as the two-terminal resistance element 7.

  A three-terminal capacitor 8 that is a three-terminal type noise filter is interposed between the second power supply line wiring patterns 4a and 4b by solder connection between the input / output terminals 8a and 8b. The ground terminal 8 c of the three-terminal capacitor 8 is connected to the ground wiring pattern 5 by solder connection, and the ground wiring pattern 5 is connected to the ground pattern layer 3 by the component via 9. The mounting position of the three-terminal capacitor 8 on the back surface of the substrate is located behind the mounting position of the IC 1 on the front surface of the substrate as shown in FIG. The second power supply line wiring pattern 4b connected to the input / output terminal 8b is connected to the first power supply line wiring pattern 2b by the interlayer via 10 passing through the hole 3b formed in the ground pattern layer 3. ing.

  The first power supply line wiring patterns 2a and 2b form a first power supply path for connecting the power supply terminal 1a of the IC 1 to the power supply circuit via the two-terminal resistance element 7, and the IC via 6a and the second power supply. The line wiring patterns 4a and 4b, the interlayer via 10 and the first power line wiring pattern 2b are connected to the power supply circuit via the three-terminal capacitor 8 in parallel with the first power supply path. A power supply path is formed. The power supply circuit (not shown) includes a battery, a switching regulator, and the like. As will be described later, the power supply circuit of the IC 1 passes through both the first power supply path and the second power supply path, or only through the second power supply path. Power is supplied to the power supply terminal 1a. That is, IC1 constitutes a load of the power feeding circuit.

  2A is an external perspective view of the three-terminal capacitor 8, and FIG. 2B is an exploded perspective view showing an internal configuration thereof.

  The three-terminal capacitor 8 is a multilayer ceramic chip capacitor or the like, and includes a through internal electrode 21 provided so as to linearly pass through a rectangular parallelepiped dielectric 20. The penetrating internal electrode 21 has both ends in the length direction connected to the pair of input / output terminals 8a and 8b. In addition, a substantially cross-shaped ground internal electrode 22 that forms a capacitance with the penetrating internal electrode 21 is provided in the dielectric 20. Both ends of the ground internal electrode 22 in the width direction are connected to the ground terminal 8c. In the dielectric 20, a plurality of through internal electrodes and ground internal electrodes (not shown) similar to the through internal electrode 21 and the ground internal electrode 22 are alternately stacked to form a plurality of capacitors. These through internal electrodes and ground internal electrodes (not shown) are also connected to the input / output terminals 8a and 8b and the ground terminal 8c, respectively, similarly to the through internal electrode 21 and the ground internal electrode 22.

  In such a configuration, the power supply path for connecting the power supply terminal 1a of the IC 1 to the power supply circuit is when the two-terminal resistance element 7 is inserted by soldering between the first power supply line wiring patterns 2a and 2b. Is composed of two paths, a first power supply path and a second power supply path. The first power supply path is a path that passes through the first power supply line wiring pattern 2a, the two-terminal resistance element 7, and the first power supply line wiring pattern 2b, and the second power supply path includes the IC via 6a, This is a path passing through the second power supply line wiring pattern 4a, the through electrode 21 of the three-terminal capacitor 8, the second power supply line wiring pattern 4b, the interlayer via 10, and the first power supply line wiring pattern 2b.

  In this case, a two-terminal resistive element 7 and a three-terminal capacitor 8 are inserted in parallel between the power supply terminal 1a of the IC 1 and the power supply circuit, and a two-terminal type is connected between the input / output terminals 8a and 8b of the three-terminal capacitor 8. The resistance element 7 is connected in parallel. Therefore, the three-terminal capacitor 8 is used as a bypass capacitor and is used as a bypass capacitor, the impedance of the power supply wiring is reduced, and the stable operation of the IC 1 is achieved.

  On the other hand, the power supply path for connecting the power supply terminal 1a of the IC 1 to the power supply circuit is the two-terminal resistance element 7 when the two-terminal resistance element 7 is not interposed between the first power supply line wiring patterns 2a and 2b. The first power supply line wiring pattern 2a, 2b is in a disconnected state at the intervening location of, and is constituted by a single path including only the second power feeding path.

  In this case, the second power supply wiring pattern 4a connected to the power supply terminal 1a and superimposed with noise, and the first power supply wiring pattern 2b and the second power supply wiring pattern 4b connected to the power feeding circuit are spatially separated. Separated. Only the three-terminal capacitor 8 is inserted between the power supply terminal 1a of the IC 1 and the power supply circuit, and only the through internal electrode 21 between the input / output terminals 8a and 8b of the three-terminal capacitor 8 is interposed alone in the power supply path. It is done. Therefore, the three-terminal capacitor 8 is used as a decoupling capacitor, and noise always passes through the three-terminal capacitor 8, and the high-frequency noise generated at the power supply terminal 1a is effectively returned to the ground terminal 1b. Noise countermeasures with a large removal effect are achieved. This noise countermeasure effect is commensurate with the use of a three-terminal capacitor 8 having a large insertion loss.

  For this reason, according to the mounting structure according to the present embodiment, the use and decoupling of the three-terminal capacitor 8 as a bypass capacitor can be achieved by attaching and detaching the two-terminal resistance element 7 between the first power supply line wiring patterns 2a and 2b. It is possible to easily switch the usage mode as a ring capacitor. Therefore, it becomes possible to easily examine which usage mode should be emphasized and design a circuit board without producing a plurality of circuit boards as in the prior art. As a result, it is possible to provide a mounting structure for a noise countermeasure electronic component that can significantly reduce the time and cost required for designing a circuit board on which the noise countermeasure electronic component is mounted.

  In order to confirm the effect produced by the mounting structure of the above-mentioned noise countermeasure electronic component, the applicant quantitatively quantifies the power source impedance and the noise countermeasure effect, which are indexes for stable operation of the IC, by a three-dimensional electromagnetic field simulation. The insertion loss, which is the indicated amount, was analyzed.

  In this simulation, the mounting structure of the above-described noise countermeasure electronic component was analyzed as a model shown in FIGS. 3 and 4, the same reference numerals are given to the same or corresponding parts as in FIG. 1 and the description thereof is omitted.

  FIG. 3 shows a model of the mounting structure A of the noise countermeasure electronic component when the two-terminal resistance element 7 is inserted between the first power supply line wiring patterns 2a and 2b, and FIG. 4 shows the first power supply line. The model of the mounting structure B of the noise countermeasure electronic component in the case where the two-terminal resistive element 7 is not interposed between the wiring patterns 2a and 2b is shown. The partial diagram (a) of each figure is an exploded perspective view of the model, the partial diagram (b) is the pattern of the first layer of the model shown in the partial diagram (a), and the partial diagram (c) is shown in the partial diagram (a). The pattern of the second layer of the model, and part (d) is a plan view showing the pattern of the third layer of the model shown in part (a).

  In the model of the mounting structure A shown in FIG. 3, the two-terminal resistance element 7 is expressed as a wiring pattern. The model of the mounting structure A shown in FIG. 3 and the model of the mounting structure B shown in FIG. 4 are such that the two-terminal resistance element 7 is as shown in FIGS. 3A and 3B in the model of the mounting structure A. On the other hand, the model of the mounting structure B is different only in that it is not shown in FIGS. 4 (a) and 4 (b).

  In each model, the first and second ports 31 and 32 are provided for analysis. As shown in FIGS. 3A and 3B and FIGS. 4A and 4B, the first port 31 has an IC via 6a connected to the power supply terminal 1a and an IC connected to the ground terminal 1b. It is provided between the vias 6b and is regarded as an impedance between the power supply terminal 1a and the ground terminal 1b of the IC1. The impedance of the first port 31 is assumed to be 50 [Ω]. Further, as shown in FIGS. 3A and 4A, the second port 32 is provided between the first wiring power supply pattern 2b and the ground pattern layer 3 connected to the power supply circuit. This is regarded as the impedance between the power supply pattern and the ground pattern.

  Using each of these models, the impedance (power supply impedance) expected from the power supply circuit side from the first port 31 was analyzed, and the insertion loss between the first port 31 and the second port 32 was analyzed.

  The graph shown in FIG. 5 shows the simulation analysis result of the power supply impedance, the horizontal axis shows the signal frequency [MHz], and the vertical axis shows the impedance [Ω]. In addition, a characteristic line 41a indicated by a solid line is a simulation analysis result of the power supply impedance in the model of the mounting structure A shown in FIG. 3, and a characteristic line 42a indicated by a dotted line is a simulation analysis of the power supply impedance in the model of the mounting structure B shown in FIG. Represents the result.

  As shown in the graph, the power supply impedance of the model of the mounting structure A represented by the characteristic line 41a is lower than that of the model of the mounting structure B represented by the characteristic line 42a. It is understood that this is a structure in which stable operation can be expected.

  The graph shown in FIG. 6 shows the simulation analysis result of the insertion loss, the horizontal axis shows the signal frequency [MHz], and the vertical axis shows the insertion loss [dB]. Further, a characteristic line 41b shown by a solid line is a simulation analysis result of the insertion loss in the model of the mounting structure A shown in FIG. 3, and a characteristic line 42b shown by a dotted line is a simulation analysis of the insertion loss in the model of the mounting structure B shown in FIG. Represents the result.

  As shown in the graph, the mounting structure B model represented by the characteristic line 42b has a larger insertion loss than the model of the mounting structure A represented by the characteristic line 41b. It is understood that the structure is more effective.

  Further, according to the mounting structure according to the present embodiment described above, since the two-terminal resistance element 7 is mounted on the substrate surface adjacent to the IC 1, the physical distance between the IC 1 and the two-terminal resistance element 7 is short. Thus, the power supply path by the first power supply wiring pattern 2a from the power supply terminal 1a of the IC 1 to the two-terminal resistance element 7 is shortened. Further, since the three-terminal capacitor 8 is mounted on the back surface of the substrate located behind the mounting position of the IC1, the physical distance between the IC1 and the three-terminal capacitor 8 is shortened, and the power supply terminal 1a of the IC1 to the three-terminal capacitor The power supply path by the IC via 6a and the second power supply wiring pattern 4a leading to the eight input / output terminals 8a is shortened. For this reason, the wiring impedance formed by the feeding path between the power supply terminal 1a and the two-terminal resistance element 7 and the wiring impedance formed by the feeding path between the power supply terminal 1a and the three-terminal capacitor 8 are reduced. Further, the impedance of the power supply wiring can be further reduced, and the noise removal effect by the three-terminal capacitor 8 is further enhanced.

  Further, in the mounting structure according to the present embodiment described above, the three-terminal capacitor 8 is used as a three-terminal type noise filter, and the through internal electrode 21 having no resistance element or induction element between the input / output terminals 8a and 8b of the three-terminal capacitor 8 is used. Therefore, the impedance between the input / output terminals 8a and 8b of the three-terminal capacitor 8 becomes small. For this reason, the impedance of the power supply wiring can be further reduced, and the noise removal effect by the three-terminal capacitor 8 is further enhanced.

  In the above embodiment, the case where the two-terminal resistance element 7 is inserted between the first power supply line wiring patterns 2a and 2b has been described. However, a two-terminal induction element such as a ferrite bead is inserted. You may comprise. What type of two-terminal element is used is appropriately selected as necessary.

  In the above-described embodiment, the case where the three-terminal capacitor 8 is inserted as the three-terminal type noise filter between the second power supply line wiring patterns 4a and 4b has been described. However, a three-terminal LC filter having an inductive element between the input and output terminals and a capacitive element between the ground terminal and a three-terminal type having a resistive element between the input and output terminals and a capacitive element between the ground terminal A three-terminal noise filter such as an RC filter may be interposed between the second power line wiring patterns 4a and 4b. What type of three-terminal noise filter is used is appropriately selected as necessary.

  The mounting structure of the noise countermeasure electronic component according to the present embodiment is used as a power noise countermeasure when designing a circuit board such as a high frequency electronic circuit in which signal transmission is performed at a high frequency. In addition, it can be obtained at low cost.

1 ... IC (load)
DESCRIPTION OF SYMBOLS 1a ... Power supply terminal 1b ... Ground terminal 2a, 2b ... 1st power supply wiring pattern 3 ... Ground pattern layer 3a, 3b ... Hole 4a, 4b ... 2nd power supply wiring pattern 5 ... Ground wiring pattern 6a, 6b ... IC via 7... Two-terminal resistance element 7 a, 7 b. Terminal of the two-terminal resistance element 7 8. Three-terminal capacitor 8 a, 8 b... Input / output terminal of the three-terminal capacitor 8 8 c. Via 10 ... interlayer via

Claims (3)

A first power supply path for connecting a power supply terminal of a load to a power supply circuit, wherein a two-terminal resistance element or a two-terminal induction element is detachably inserted;
A second power supply path for connecting the power supply terminal to the power supply circuit in parallel with the first power supply path, wherein a three-terminal noise filter having an input / output terminal and a ground terminal is interposed between the input / output terminals; A mounting structure for noise-reducing electronic components configured with a circuit board. The first power supply path is formed as a first power line pattern on the circuit board surface on which the load is mounted, and the two-terminal resistance element or the two-terminal induction element is adjacent to the load. Mounted on the substrate surface,
The second power supply path is formed as a second power line wiring pattern on the back surface of the circuit board, and the three-terminal noise filter is mounted on the back surface of the board located behind the load mounting position. The mounting structure of the noise-reducing electronic component according to claim 1   3. The mounting structure for noise-reducing electronic components according to claim 1, wherein the three-terminal type noise filter is a three-terminal capacitor.

Images