JP2011035222A - Electronic equipment and printed wiring board thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment that greatly reduces radiation EMI of high frequency and uses a printed wiring board low in manufacturing cost. <P>SOLUTION: In the electronic equipment including the printed wiring board mounted with an electronic component having a power supply terminal, a ground terminal and a signal terminal, the printed wiring board includes a power supply plane and a ground plane of the electronic component, and an open stub wiring whose electric length is 1/4 of a wavelength at a parallel plate resonance frequency generated between the power supply plane and ground plane is connected to a power supply wiring passing through the power supply terminal and power supply plane of the electronic component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information processing apparatus, an electronic apparatus such as a communication apparatus, and a printed wiring board used therefor in consideration of noise countermeasures corresponding to, for example, standards for unwanted electromagnetic wave noise regulations.

  Conventionally, unnecessary electromagnetic noise generated inside an electronic device and external noise that propagates from the outside and enters the inside of the electronic device has been a serious problem in terms of the influence on the inside and outside of the electronic device. Therefore, EMC (Electromagnetic Compatibility) design that prevents the generation of unnecessary electromagnetic noise generated inside the electronic device or ensures the external noise resistance is important.

  In particular, in recent years, a problem as a source of unnecessary electromagnetic noise has been that when an electronic component mounted on a printed wiring board is switched, the power supply of the electronic component is changed to a power plane provided inside the printed wiring board. High-frequency noise flowing in. Usually, a printed wiring board has a structure in which a power plane and a ground plane are opposed to each other. Due to the generation of parallel plate resonance using the high frequency noise between the power plane and the ground plane as an excitation source, very large unnecessary electromagnetic noise is generated. May radiate to the surroundings.

  As a countermeasure against unnecessary electromagnetic wave noise, there is a conventional technique in which an electronic component called a decoupling capacitor is arranged between a power supply terminal and a power supply plane of a printed wiring board. However, although this technology is effective for reducing noise on the low frequency side, which occurs at the power of about 1 GHz in the power supply in the electronic component, not only the noise emission on the high frequency side cannot be reduced, but also depending on the case. It has become clear that there is a problem of increased noise.

  The unnecessary electromagnetic noise is referred to as EMI (Electromagnetic Interference), and in Japan so as not to affect other electronic devices, VCCI (Voluntary Control Council for Interference by Data Processing Equipment) It is regulated by various standards established by the FCC in the United States, the FCC in the United States, and the EN in Europe. As of March 2009, products used in the home environment in the VCCI are defined as Class B information technology devices, and the electric field intensity of radiated EMI is regulated in the frequency band of 30 MHz to 1 GHz. It is scheduled to be further expanded to 1 GHz to 6 GHz in October, and countermeasures against unnecessary electromagnetic wave noise in this extended frequency band are urgently required in designing electronic devices.

  In order to reduce such radiated EMI problems, the electrical length of the power supply wiring of the power supply path that supplies power from the main power supply to the electronic component (value obtained by multiplying the actual wiring length by the wavelength reduction rate of the substrate material) Is a quarter of the upper limit frequency of radiated EMI, and a technique of a printed wiring board in which one capacitor is connected to each end of the power supply path is disclosed (for example, see Patent Document 1). In addition, by arranging a stub wiring formed so that the electrical length in the mounting substrate is a quarter wavelength that is an integral multiple of the operating frequency of the electronic component, an antiphase current is excited in the power feeding system, and noise is generated. A technique of a printed wiring board that reduces current is disclosed (for example, see Patent Document 2).

JP 2001-119110 A JP 2004-140210 A

  Conventionally, it is as described above, and in Patent Document 1, it is necessary to connect a decoupling capacitor to both ends of a power line having a length of ¼ wavelength, but other electronic components are mounted particularly near the main power source. In such a case, it is difficult to dispose the decoupling capacitor in the portion. Even if the decoupling capacitor is disposed, the decoupling capacitor is compared with the impedance of the power plane of the printed wiring board at a frequency of 1 GHz or more. It is expected that the impedance of the above will be the same or higher and the desired effect cannot be obtained.

  For example, a capacitor of 1608 size has a resistance component and an inductance component of about 0.5 nH in series in addition to the capacitance component, and when the inductance to the ground plane of the via is 0.5 nH, the combined impedance of the capacitor and the via is 1 GHz. It becomes about 6Ω, which is not negligible compared to the impedance of the power plane. In addition, regarding the specific length of the power supply wiring, measures based on the upper limit frequency at which radiated EMI occurs have been studied. However, when designing electronic equipment, the upper limit frequency of radiated EMI that exceeds the regulation value is itself. The difficulty of estimation is also a problem.

  In the prior art of Patent Document 2, by using open stub wiring, it is possible to attenuate noise that is an odd multiple of the operating frequency of electronic components mounted on a printed wiring board, but between the power plane and the ground plane of the printed wiring board. This resonance frequency cannot be particularly addressed, and there is a problem that radiation EMI at this resonance frequency may not be sufficiently suppressed. In addition, when the semiconductor device connected to the power supply of the electronic component is a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), it may not operate at a frequency that is multiplied or divided based on a single clock frequency. However, there is a problem that such frequencies cannot be handled.

  Further, in signal transmission in an electronic device, high frequency noises in various frequency bands are generated due to reflection caused by not all circuits having matching characteristic impedance. In the high-frequency spectrum of the current flowing through the power supply terminal of the electronic component when the electronic device is actually operated, not only the harmonic component of the operating frequency of the electronic component but also other spectra are observed. On the other hand, in the radiated EMI characteristics of the printed wiring board, the radiated electrolysis intensity at the resonance frequency between the power plane and the ground plane is 40 dBμV / m or more (that is, 100 times based on 0 dBμV / m as compared with the non-resonant frequency band). And so on). Therefore, in order to suppress the radiated EMI caused by the power plane, high frequency noise generated by the operation of the electronic component should not be given between the power plane and the ground plane at the resonance frequency between the power plane and the ground plane. It is important to.

  Since the resonance frequency at which this radiated EMI becomes large substantially coincides with the frequency at which a partial peak of the input impedance seen from the power supply terminal and the ground terminal of the electronic component is seen, the power supply of many printed wiring boards in recent years. A simulator for analyzing the input impedance between the terminal land and the ground terminal land and the S-parameter is commercially available. In a relatively low frequency band, simulation by the simulator is performed to improve the input impedance by adding a decoupling capacitor or changing the position, or by using a ferrite bead or a three-terminal capacitor to reduce high-frequency noise from electronic components. Countermeasures against radiated EMI are taken. However, as described above, the capacitor measures have a problem that the impedance becomes high and the effect becomes low at 1 GHz or more, and there is a problem that the manufacturing cost is greatly increased when a ferrite bead or a three-terminal capacitor is used for each power supply terminal.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain an electronic device that can significantly reduce radiation EMI at a high frequency and uses a printed wiring board at a low manufacturing cost.

  The electronic device of the present invention is an electronic device including a printed wiring board on which an electronic component having a power supply terminal, a ground terminal, and a signal terminal is mounted, and the printed wiring board is electrically connected to the ground terminal. A ground plane, a power plane that is provided substantially opposite to the ground plane and is electrically connected to the power terminal via a power wiring, and is connected to the power wiring, and refers to the ground plane. An open stub wiring serving as a surface is provided, and the open stub wiring has an electrical length of ¼ wavelength of a parallel plate resonance frequency generated between the power plane and the ground plane.

  According to the present invention, in the printed wiring board provided in the electronic device, the electrical length of the quarter wavelength of the parallel plate resonance frequency generated between the power plane and the ground plane is formed in the power wiring via the power terminal and the power plane of the electronic component. Since the open stub wiring is connected, it is possible to effectively attenuate the high frequency noise of the resonance frequency at the high frequency, and to suppress radiated EMI from the electronic device.

1 is a schematic top view of a printed wiring board according to Embodiment 1 of the present invention. It is a schematic top view which mounted the electronic component and capacitor of the printed wiring board which concern on Embodiment 1 of this invention. It is a schematic sectional drawing of the printed wiring board which concerns on Embodiment 1 of this invention. It is a graph which shows the filter characteristic of the electronic device which concerns on Embodiment 1 of this invention. 1 is a schematic top view of a printed wiring board according to Embodiment 1 of the present invention. It is a schematic top view of the printed wiring board concerning Embodiment 2 of this invention. It is a schematic top view of the printed wiring board concerning Embodiment 2 of this invention. It is a graph which shows the filter characteristic of the electronic device which concerns on Embodiment 2 of this invention. It is a schematic top view of the printed wiring board concerning Embodiment 3 of this invention. It is a schematic sectional drawing of the printed wiring board which concerns on Embodiment 4 of this invention. It is a schematic sectional drawing of the printed wiring board which concerns on Embodiment 4 of this invention. It is a graph which shows the relationship between the length of the side of the power plane which concerns on Example 1 of this invention, and a resonant frequency. It is a graph which shows the relationship between the diameter of the power plane which concerns on Example 2 of this invention, and a resonant frequency.

Hereinafter, a printed wiring board included in an electronic device according to each embodiment of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic top view of a printed wiring board 1 according to Embodiment 1, FIG. 2 is a schematic top view in which an electronic component 2 and a capacitor 3 are mounted on the printed wiring board 1, and FIG. 2 shows a schematic cross-sectional view along line II of FIG. The illustration of the electronic device provided with the printed wiring board 1 is omitted.

  1 to 3, on the mounting surface of the printed wiring board 1, a power terminal, a ground terminal, an electronic component 2 having a signal terminal, an electronic component signal terminal land 8a for mounting a chip capacitor 3, and an electronic component power source A terminal land 8b, an electronic component ground terminal land 8c, and a capacitor land 9 are provided. The electronic component power supply terminal land 8b is connected to the power supply through hole 10a by the power supply wiring 5, and an open stub wiring 7 having the other end opened is connected to the power supply wiring 5. The power through hole 10a is a conductor electrically connected to the power plane 4 arranged in the inner layer of the printed wiring board, and the ground through hole 10b is electrically connected to the ground plane 6 arranged in the inner layer of the printed wiring board. Conductor. In other words, the electronic component power terminal land 8b is connected to the power plane 4 via the power wiring 5 and the power through hole 10a, and the electronic component ground terminal land 8c is connected to the ground plane 6 via the ground through hole 10b. Connected to. The printed wiring board 1 is a multilayer printed wiring board composed of a signal layer, a power supply layer, and a ground layer. In FIG. 3, in order to facilitate understanding of the configuration, the signal layer and the ground plane that are the surfaces of the printed wiring board 1 are used. 6 includes a ground layer including 6, a power layer including the power plane 4, and a signal layer which is the back surface of the printed wiring board 1.

  As shown in FIG. 2, when the power plane 4 has a rectangular shape having a long side of a and a short side of b, the power plane 4 and the ground plane 6 are described as in Example 1 described later. The lowest resonance frequency of parallel plate resonance occurring between the two is the frequency at which the electrical length twice the long side a becomes one wavelength. Therefore, in the printed wiring board 1 on which the electronic component is mounted, in order to reduce high frequency noise of the lowest resonance frequency between the power plane 4 and the power plane 6, and to suppress radiated EMI from the electronic equipment, An open stub wiring 7 having an electrical length that is ½ of the long side a of the power supply plane 2 is provided on the power supply wiring 5 provided between the land 8 b and the rectangular power supply plane 4.

FIG. 4 shows filter characteristics obtained by providing the power supply wiring 5 with the open stub wiring 7 having an electrical length that is ½ of the long side of the power supply plane 4. In FIG. 4, 11a, 11b, 11c, and 11d indicate characteristics when the wiring widths of the open stub wirings 7 are different, and the wiring widths have a relationship of 11a <11b <11c <11d. As shown in FIG. 4, when the open stub wiring 7 is wider than the power supply wiring 5, a better attenuation characteristic is provided. Conversely, when the open stub wiring 7 is narrower than the power supply wiring 5, the noise attenuation effect is obtained. Fades. FIG. 5 shows a configuration in which the wiring width W ₂ of the open stub wiring 7 is larger than the wiring width W ₁ of the power supply wiring 5 in consideration of this characteristic.

  Here, the operation of the open stub wiring 7 will be described. In the electronic device, high frequency noise leaking from the power supply terminal of the electronic component travels toward the power supply plane 4 through the power supply wiring 5. At this time, when high-frequency noise progresses in the open stub wiring 7 connected to the power supply wiring 5, the open stub wiring 7 is totally open at the tip because it is an open end, and returns to the branch portion of the power supply wiring 5. The high-frequency noise totally reflected at the tip of the open stub wiring 7 travels from the branch portion of the power wiring 5 toward the power plane 4 because the round trip of the open stub wiring 7 has a half wavelength and the phase is shifted by 180 degrees. To cancel the voltage. Therefore, high frequency noise transmitted to the power plane 4 can be suppressed, and high frequency noise generated by resonance between the power plane 4 and the ground plane 6 can be reduced.

  From the above, since the electrical length of the open stub wiring 7 is important, that is, the wiring length corresponding to the electrical length, the shape is not limited to a straight line and may be bent. However, since there is a slight capacitance component at the open end of the open stub wiring, it is better to set the electrical length slightly shorter than ½ wavelength. The open stub wiring 7 can suppress not only the frequency at which the half wavelength is equal to the electrical length but also the radiation EMI having a higher frequency of 2n + 1 times (n is an integer).

  On the other hand, according to the above configuration, since the voltage minimum and the current become the maximum at the branch portion of the power supply wiring 5 and the open stub wiring 7, when the branch portion is physically close to the power supply plane 4, the leakage current is There is a possibility that high-frequency noise is applied between the plane 4 and the ground plane 6 and the effect of suppressing the radiation EMI by the open stub wiring 7 is diminished. In order to avoid this, a method of separating the distance from the branch portion of the power supply wiring 2 to the power supply plane 4 is effective. In addition, the fact that the open stub wiring 7 uses the power plane 4 as a reference plane directly gives high frequency noise to the power plane 4, so that the effect of suppressing radiated EMI cannot be expected. Therefore, the open stub wiring 7 needs to use the ground plane 6 instead of the power plane 4 as a reference plane.

  Further, in the case of a printed wiring board having a large number of layers, if the open stub wiring 7 is arranged between the ground plane 6 and the ground plane 6, radiation is caused more than by the configuration of the open stub wiring 7 and the ground plane 6 arranged on the surface layer. EMI decreases. In that case, in order to avoid resonance between the ground planes, it is necessary to provide ground through holes for connecting the ground planes at intervals sufficiently smaller than the wavelength in the printed wiring board 1 at that frequency. Therefore, it is preferable to mount electronic components that cause high-frequency noise on the surface of the printed wiring board closer to the ground plane 6 instead of the power plane 4 in order to provide the open stub wiring 7 at an effective position.

  As described above, in the printed wiring board 1 on which the electronic component is mounted, the power wiring 5 provided between the electronic component power terminal land 8b and the rectangular power plane 4 is ½ of the long side of the power plane 4. By providing the open stub wiring 7 having the electrical length of the length, the high-frequency noise transmitted to the power plane 4 is suppressed, and the lowest high-frequency noise between the power plane 4 and the ground plane 6 is reduced. The radiated EMI of the device can be suppressed.

  The relationship between the shape of the power plane in the printed wiring board of the present invention and the resonance frequency of the parallel plate resonance that occurs between the power plane and the ground plane, the calculation method, and the calculation of the open stub wiring length that suppresses noise at the resonance frequency A specific example of the method is shown below.

When the power plane is rectangular, the resonance frequency f _{mn at} a high frequency is obtained as follows by solving the Maxwell equation in an isotropic medium of an orthogonal coordinate system by applying boundary conditions based on the structure.

但し、ｃは光速、ε_ｒは電源プレーンとグランドプレーン間にあるプリント配線板材料の比誘電率、ｍ＝０、１、２、…、ｎ＝０、１、２、…である。このとき、最も低い共振周波数ｆ_１０は、ｍ＝１、ｎ＝０の場合であり次式となる。

Where c is the speed of light, ε _r is the relative dielectric constant of the printed wiring board material between the power plane and the ground plane, and m = 0, 1, 2,..., N = 0, 1, 2,. In this case, the lowest resonance frequency _{f 10} is the case of m = 1, n = 0 the following equation.

Further, the open stub wiring length L _mn for canceling the high frequency noise at the resonance frequency shown in Expression 1 is obtained by the following expression.

但し、ε_ｒｅｆｆはオープンスタブ配線や、その周囲の構造や材料定数によって決定される実効比誘電率である。

Here, ε _ref is an effective relative dielectric constant determined by the open stub wiring, the surrounding structure, and material constants.

From the above equations (2) and (3), the open stub line length L ₁₀ to cancel the high-frequency noise in the lowest resonance frequency f _10, obtained by the following equation.

したがって、電源配線５に電源プレーン２の長辺ａの１／２の長さの電気長としたオープンスタブ配線７を設けることにより、電源プレーン６の最も低い共振周波数の高周波ノイズを減らすことができ、電子機器の放射ＥＭＩを抑制することができる。

Therefore, by providing the power supply wiring 5 with the open stub wiring 7 having an electrical length that is ½ of the long side a of the power supply plane 2, high frequency noise of the lowest resonance frequency of the power supply plane 6 can be reduced. The emission EMI of electronic equipment can be suppressed.

Next, specific examples of the resonance frequency f _mn are shown in Table 1. Here, for simplicity, the case where the power plane 4 is a square of a = b = 60 mm is described. Further, the relative dielectric constant ε _{r is set} to 4.3.

When the power plane 4 is a square a = b, the open stub wiring L _mn for canceling high-frequency noise is expressed by the following equation from Equation 3.

したがって、表１の共振周波数に対応したオープンスタブ配線の長さＬ_ｍｎは、表２のとおりとなる。

Therefore, the length L _mn of the open stub wiring corresponding to the resonance frequency in Table 1 is as shown in Table 2.

  According to the above, if the assumed high frequency noise of the electronic component is 2 GHz or less, by connecting the open stub wirings with electrical lengths of about 30 mm and about 21.1 mm to the power supply wirings, these are m = 1, n Since it acts as a filter at the resonance frequency of = 0, m = 1, and n = 1, it is possible to reduce noise to the power supply plane and suppress radiation EMI of the electronic device.

In the present invention, a study on the resonance frequency between the power plane and the ground plane when the power plane is square is shown in FIG. In the figure, the vertical axis represents the resonance frequency, the horizontal axis represents the length of one side, and resonance occurs at f ₁₀ , f ₁₁ , f ₂₁ ,. If the a = b = 60mm, since cross the line of _{f 10} and _{f 11} to 2 _GHz, it open stub line which is a filter at the resonant frequency of _{f 10} and _{f 11} are required two are from FIG. I can judge. f _10, if the shape of the power plane is not square (a ≠ b) likewise the resonance frequency is obtained by taking the long side on the horizontal axis.

When the power plane is circular, the resonance frequency f _{mn at} a high frequency is obtained as follows by solving the Maxwell equation in an isotropic medium of a cylindrical coordinate system and applying boundary conditions based on the structure.

但し、ｃは光速、ｒは円形電源プレーンの半径、ε_ｒは電源プレーンとグランドプレーン間にあるプリント配線板材料の比誘電率、χ_ｍｎはｍ次Ｂｅｓｓｅｌ関数（ｍ＝０、１、２、…）のｎ番目の零点（Ｊｍ（ζ）＝０の根ζの小さい方からｎ番目のもの）である。

Where c is the speed of light, r is the radius of the circular power plane, ε _r is the relative permittivity of the printed wiring board material between the power plane and the ground plane, and χ _mn is the mth order Bessel function (m = 0, 1, 2,. )) (The nth one from the smaller root ζ of Jm (ζ) = 0).

When the diameter of the circular power plane is d, the open stub wiring length L _mn that cancels high-frequency noise at this resonance frequency is obtained by the following equation.

Next, Table 3 shows the nth zero χ _mn of the mth order Bessel function.

The resonance frequency f _mn when the diameter is d = 2r = 60 mm is as shown in Table 4 from Equation 6 when the relative dielectric constant is 4.3.

From Expression 7, the length L _mn of the open stub wiring corresponding to the resonance frequency in Table 4 is as shown in Table 5.

  As shown in Table 4, when the power plane is circular, the lowest resonance mode is not m = 0 and n = 1, but m = 1 and n = 1. If the assumed high frequency noise of the electronic component is up to 2 GHz, the open stub wiring has an electrical length of about 25.6 mm corresponding to m = 1 and n = 1, that is, about 0.43 times the diameter of the circular power plane 60 mm. By connecting to the power supply wiring, the radiated EMI of the electronic device at the resonance frequency can be suppressed regardless of the connection position of the power supply wiring to the power supply plane.

In the present invention, a study on the resonance frequency between the power plane and the ground plane when the power plane is circular is shown in FIG. In the figure, the vertical axis represents the resonance frequency, the horizontal axis represents the diameter, and resonance occurs at f ₁₁ , f ₂₁ , f ₀₁ . If the d = 2r = 60mm, since cross the line of _{f 11} to 2 _GHz, it open stub line which is a filter at the resonant frequency of _{f 11} is required one can be determined from FIG.

  As in the above-described embodiments, by setting the power plane to an arbitrary shape and size such as a square or a circle, the resonance frequency at a high frequency can be predicted at the design stage of the printed wiring board. Then, as in Embodiment 1 of the present invention, radiation EMI can be suppressed by providing an open stub wiring corresponding to this resonance frequency. Since the present invention is realized not by a short stub wiring but by an open stub wiring having a half length as a signal transmission filter, it is possible to deal with noise related to a power supply.

  In addition, the said Example is applicable not only to the printed wiring board of an electronic device but the attenuation | damping of the high frequency noise by resonance of the power plane and ground plane which are comprised in an electronic component. For example, for an electronic component having a power plane of 25 mm square, an open stub wiring having an electrical length of 12.5 mm is provided between the power source of the semiconductor chip mounted on the substrate of the electronic component and the power plane, for example, relative dielectric. When the rate is 4.3, the radiated EMI at 2.893 GHz, which is the lowest resonance frequency, can be suppressed.

Embodiment 2. FIG.
6 and 7 are schematic top views of the printed wiring board according to Embodiment 2 of the present invention. Components denoted by the same reference numerals as those in FIG. 1 indicate the same configurations. The shape of the power plane 24 in FIG. 6 is a circle, and the shape of the power plane 4 in FIG. When the shape of the power supply plane is determined in this way, the resonance frequency between the power supply plane and the ground plane is changed according to the relationship between the shape of the power supply plane and the resonance frequency described in Example 1 and Example 2 of the first embodiment. The mode is uniquely determined. Accordingly, in order from the lowest resonance frequency, two or more open stub lines corresponding to the resonance frequency are connected to the power supply line, thereby suppressing radiation EMI at the resonance frequency corresponding to the electrical length of the open stub line. Is obtained. 6 and 7, the first open stub wiring 7a and the second open stub wiring 7b are connected to both sides of the power supply wiring, respectively. Thereby, radiation | emission EMI in two resonance frequencies can be suppressed from the one where a resonance frequency is low.

  FIG. 8 shows filter characteristics obtained by providing the power supply wiring 5 with the open stub wirings 7a and 7b shown in FIGS. In FIG. 8, 11a, 11b, 11c, and 11d indicate characteristics when the wiring widths of the open stub wirings 7 are different, and the wiring widths have a relationship of 11a <11b <11c <11d. As in the first embodiment, as shown in FIG. 8, a larger attenuation width is provided when the open stub lines 7 a and 7 b are wider than the power supply line 5.

Embodiment 3 FIG.
FIG. 9 shows a schematic top view of a printed wiring board according to Embodiment 3 of the present invention. In addition to the power supply plane 4 of the first embodiment, this printed wiring board includes a rectangular main power supply plane 12 in the same layer or other layers of the power supply plane 4 and the printed wiring board. The power supply plane 12 is connected via a low-pass filter 13.

  Here, the low-pass filter 13 satisfies the condition that does not cause the resonance shown in FIG. 12 described in the first embodiment. For example, if it is a low-pass filter of 300 MHz or less and the main power plane 12 has a long side of 200 mm or less, even if high-frequency noise of 300 MHz leaks from the power plane 4 to the main power plane 12, Since no resonance occurs between the ground planes, radiation EMI is suppressed. Even when the main power plane is made circular, the radiated EMI can be similarly suppressed by making the low-pass filter to be connected satisfy the condition for causing no resonance shown in FIG. 13 described in the second embodiment. However, at a frequency of 1 GHz or less, a chip capacitor for suppressing resonance between the power plane and the ground plane also works effectively.

Embodiment 4 FIG.
10 and 11 are schematic cross-sectional views of the printed wiring board according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.

  As shown in FIG. 10, in the build-up printed wiring board, the power supply wiring 5 is provided between the laser via 14 and the power supply through hole 10a by drawing from the surface layer to the second layer by the power supply laser via 14, and the embodiment is provided in that portion. By connecting the open stub wiring 7 having a predetermined length described in 1, it is possible to suppress the radiated EMI of high frequency noise as in the first embodiment. The build-up printed wiring board is advantageous for electronic parts such as BGA (Ball Grid Array) because the wiring can be drawn into the inner layer once.

  Moreover, FIG. 11 shows the printed wiring board manufactured by bonding the printed wiring boards together. Similar to the build-up specification printed wiring board, the power supply wiring 5 is provided from the surface layer to the inner layer of the printed wiring board by the power supply blind via 15 and the power supply wiring 5 is provided between the blind via 15 and the power supply through hole 10a. By connecting the open stub wiring 7 having a predetermined length described in the above, the radiation EMI of high frequency noise can be similarly suppressed.

1 Printed wiring board 2 Electronic component 3 Chip capacitor 4 Power plane (square)
5 power supply wiring 6 ground plane 7 open stub wiring 7a first open stub wiring 7b second open stub wiring 8a electronic component signal terminal land 8b electronic component power terminal land 8c electronic component ground terminal land 9 capacitor land 10a Power supply through hole 10b Ground through hole 11a Insertion loss when the open stub wiring width is the same as the power supply wiring 11b Insertion loss when the open stub wiring width is twice that of the power supply wiring 11c Open stub wiring width as the power supply Insertion loss 11d when the width is three times the wiring Insertion loss when the open stub wiring width is four times that of the power supply wiring 12 Core power plane 13 Low-pass filter 14 Laser via connecting the 1-2 layers ( Laser Via Hole)
15 Blind Via Hole
24 Power plane (circular)

Claims (8)

In an electronic device including a printed wiring board for mounting an electronic component having a power terminal, a ground terminal, and a signal terminal, the printed wiring board is
A ground plane electrically connected to the ground terminal;
A power supply plane that is provided substantially opposite to the ground plane and is electrically connected to the power supply terminal via a power supply wiring,
Connected to the power supply wiring, comprising an open stub wiring with the ground plane as a reference surface,
The open stub wiring has an electrical length of ¼ wavelength of a parallel plate resonance frequency generated between the power plane and the ground plane.   2. The electronic device according to claim 1, wherein the open stub wiring has an electrical length of ¼ wavelength of the lowest resonance frequency among parallel plate resonance frequencies generated between the power plane and the ground plane. . The power plane has a rectangular shape;
The electronic device according to claim 1, wherein the open stub wiring has an electrical length that is approximately a half of an electrical length of a long side of the power plane. The power plane is circular,
The electronic device according to claim 1, wherein the open stub wiring has an electrical length that is approximately 0.43 times the electrical length of the diameter of the power plane.   The open stub wiring is composed of a plurality of open stub wirings having an electrical length of ¼ wavelength of each of the plurality of resonance frequencies in order from the lowest among the parallel plate resonance frequencies generated between the power plane and the ground plane. The electronic device according to claim 1.   The electronic device according to claim 1, wherein a wiring width of the open stub wiring is larger than a wiring width of the power supply wiring. The printed wiring board further includes a basic power plane, a low-pass filter,
The electronic device according to claim 1, wherein the power plane is connected to the backbone power plane through the low-pass filter. In a printed wiring board including a mounting surface for mounting an electronic component having a power terminal, a ground terminal, and a signal terminal,
A ground plane electrically connected to the ground terminal;
A power supply plane that is provided substantially opposite to the ground plane and is electrically connected to the power supply terminal via a power supply wiring,
Connected to the power supply wiring, comprising an open stub wiring with the ground plane as a reference surface,
The printed wiring board, wherein the open stub wiring has an electrical length of ¼ wavelength of a parallel plate resonance frequency generated between the power plane and the ground plane.

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