JP2008071948A - Printed circuit board, method of mounting electronic component, and control device of image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board which prevents impedance mismatching in connecting pads and wiring patterns which constitute signal lines for high-speed signals such as high-speed differential signals and can secure the strength reliability by soldering of connector portions. <P>SOLUTION: The printed circuit board includes a group of pads 8 whereon surface mounting connectors are to be mounted by soldering the connector leads to the pads; the wiring patterns 6a and 6b which constitute the signal lines for high-speed signals which are be connected to the pads 8a and 8b out of the group of pads 8; and the wiring patterns 5a and 5b which constitute signal lines for other signals than high-speed signals which are to be connected to a plurality of pads 8c out of the group of pads 8. The width of the pads 8a and 8b to which the wiring patterns 6a and 6b are to be connected is made narrower than that of the pads 8c to which the wiring patterns 5a and 5b are to be connected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printed wiring board, an electronic component mounting method, and a control device for an image forming apparatus.

In recent years, in order to improve the mountability of electronic components on a printed wiring board, for example, as in Patent Document 1 below, the size of at least one land in the electronic component mounting pad row of the printed wiring board is increased. It is disclosed that the land is made smaller and this land is used as a positioning reference.
JP 2001-7491 A

  By the way, by using the manufacturing method of Patent Document 1, it is possible to improve the mountability of electronic components on a printed wiring board and to secure the soldering strength of the electronic components. When applied to a pad to which a signal line is connected, it is necessary to match the impedance.

  In recent years, high-speed differential signal transmission methods such as Serial-ATA, PCI-Express, and the like have been taken with the increase in the speed of signals operating on a printed wiring board. In order to transmit a high-speed signal on a printed wiring board, it is standardized to match the impedance from the sending end to the receiving end of the wiring pattern forming the signal line.

  Impedance matching in this way is not only because the reflection of energy occurs at the point of change of impedance when characteristic impedance varies, but the waveform is distorted and the waveform quality is deteriorated. In addition to radiating radio waves to stand, there is a problem in EMC (electromagnetic compatibility).

  For example, as shown in FIG. 6, a high-speed differential signal line wiring pattern 105 a is connected to the device 103 on the printed wiring board 101, and a high-speed differential signal line wiring pattern is connected to the device 4 on the printed wiring board 102. 105 b is connected, and the wiring patterns 105 a and 105 b are connected via a connector 106. At this time, it is necessary to match the impedance value of the pad portion on which the connector 106 is mounted within the standard of the transmission method.

  Here, parameters for determining the impedance of the differential wiring pattern will be described with reference to FIG. FIG. 7 is a cross-sectional view of the printed wiring board.

  As shown in FIG. 7, the printed wiring board 200 is configured by laminating a conductor layer 202 and a dielectric 203, and a high-speed differential signal type wiring pattern 201 is wound on the surface layer of the printed wiring board 200. A resist is applied so as to cover the wiring pattern 201 of the high-speed differential signal system. In such a printed wiring board 200, the impedance between the high-speed differential signal wiring pattern 201 and the conductor layer 202 is set to a predetermined standard value. The parameters that determine the impedance of the high-speed differential signal wiring pattern 201 include the width W of the high-speed differential signal wiring pattern 201, the inter-pattern gap G between the high-speed differential signal wiring patterns 201, and the high-speed differential signal wiring pattern 201. This is determined by the thickness D of the differential signal wiring pattern 201 and the dielectric 203 in the vicinity thereof.

  Incidentally, the impedance of the connector 106 connecting the wiring patterns 105a and 105b on the printed wiring board 101 and the printed wiring boards 101 and 102 shown in FIG. 6 is generally controlled according to the standard to be transmitted. A portion for mounting the connector 106 on the printed wiring boards 101 and 102 has a pad for mounting. For this reason, since this pad portion is wider than the width of each wiring pattern 105a, 105b, the impedance at this portion becomes lower than the standard, and impedance mismatching occurs.

  Therefore, when the printed wiring boards 101 and 102 to which the wiring patterns 105a and 105b are connected via the connector 106 are provided in a control device of an image forming apparatus such as a copying machine or a printer, as described above. When impedance mismatch occurs, the image signal as a high-speed differential signal is disturbed and the image quality is degraded.

  Therefore, in order to prevent impedance mismatch, it is considered to increase the impedance of the pad portion on which the connector 106 is mounted by narrowing the pad width for mounting the connector 106 on the printed wiring boards 101 and 102 by soldering. It is done.

  However, by thinning the entire pad group on which the connector 106 is mounted by soldering, when soldering to electrically connect the pad portion on which the connector lead of the connector is mounted, it is perpendicular to the connector lead of the connector. The amount of solder to be soldered between the bent portion and the pad on the printed wiring board is reduced. For this reason, the soldering strength of the connector becomes weak, and it becomes impossible to ensure the reliability of the strength at the connector portion due to a change with time.

  Therefore, the present invention suppresses impedance mismatch when a wiring pattern that forms a signal line of a high-speed signal such as a high-speed differential signal is connected to the pad, and further ensures strength reliability by soldering at the connector portion. An object of the present invention is to provide a printed wiring board, a method for mounting an electronic component, and a control device for an image forming apparatus.

  In order to achieve the above object, the invention according to claim 1 is directed to a pad group on which a connector for surface mounting is mounted by soldering with a connector lead, and a high speed connected to the first pad in the pad group. In a printed wiring board having a first wiring pattern that forms a signal line of a signal and a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the pad group, The pad width of the first pad to which the first wiring pattern is connected is narrower than the pad width of the second pad to which the second wiring pattern is connected.

  According to a second aspect of the present invention, there is provided a pad group on which a surface mounting connector is mounted by soldering with a connector lead, and a signal line of a high-speed signal connected to the first pad in the pad group. In a printed wiring board having a first wiring pattern to be formed and a second wiring pattern for forming a signal line other than the high-speed signal connected to a second pad in the pad group, the first wiring The size of a stub that is a soldering portion of the first pad to which the pattern is connected to the connector lead is soldered to the connector lead of the second pad to which the second wiring pattern is connected. It is characterized by being smaller than the size of the stub that is a part.

  According to a third aspect of the present invention, there is provided a pad group on which a surface mounting connector is mounted by soldering with a connector lead, and a signal line for a high-speed signal connected to the first pad in the pad group. In a printed wiring board having a first wiring pattern to be formed and a second wiring pattern for forming a signal line other than the high-speed signal connected to a second pad in the pad group, the first wiring The pad width of the first pad to which the pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected, and the first pad to which the first wiring pattern is connected The size of the stub, which is a soldered portion of one pad with the connector lead, is determined by the soldered portion of the second pad to which the second wiring pattern is connected with the connector lead. It is characterized by smaller than the size of the stub that.

  According to a fourth aspect of the present invention, the high-speed signal is a differential transmission system signal.

  According to a fifth aspect of the present invention, the pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the vicinity of the conductor layer where the first pad of the printed wiring board is located. It is characterized in that the thickness of the dielectric in the above is 0.15 mm.

  According to a sixth aspect of the present invention, the size of the stub of the first pad to which the first wiring pattern is connected is 0.1 mm, and the conductor having the first pad of the printed wiring board is provided. The thickness of the dielectric in the vicinity of the layer is 0.15 mm.

  According to a seventh aspect of the present invention, the pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the first pad to which the first wiring pattern is connected. The size of the stub is 0.1 mm, and the thickness of the dielectric in the vicinity of the conductor layer on which the first pad of the printed wiring board is located is 0.15 mm.

  The invention according to claim 8 is characterized in that an input / output device is connected to each of the first wiring pattern and the second wiring pattern.

  The invention described in claim 9 is characterized in that the layer structure of the substrate comprises at least four layers.

  According to a tenth aspect of the present invention, there is provided a pad group on which a surface mounting connector is mounted by soldering with a connector lead, and a signal line for a high-speed signal connected to the first pad in the pad group. An electronic component in which a first wiring pattern to be formed and a second wiring pattern for forming a signal line other than the high-speed signal connected to a second pad in the pad group are mounted on a printed wiring board. In the mounting method, the pad width of the first pad to which the first wiring pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected. Yes.

  According to an eleventh aspect of the present invention, there is provided a pad group on which a surface mounting connector is mounted by soldering with a connector lead, and a signal line of a high-speed signal connected to the first pad in the pad group. An electronic component in which a first wiring pattern to be formed and a second wiring pattern for forming a signal line other than the high-speed signal connected to a second pad in the pad group are mounted on a printed wiring board. In the mounting method, the size of the stub that is a soldered portion of the first pad to which the first wiring pattern is connected to the connector lead is set to the size of the second pad to which the second wiring pattern is connected. It is characterized in that it is made smaller than the size of the stub which is a soldered portion of the pad with the connector lead.

  According to a twelfth aspect of the present invention, a pad group on which a connector for surface mounting is mounted by soldering with a connector lead, and a signal line of a high-speed signal connected to the first pad in the pad group are provided. An electronic component in which a first wiring pattern to be formed and a second wiring pattern for forming a signal line other than the high-speed signal connected to a second pad in the pad group are mounted on a printed wiring board. In the mounting method, the pad width of the first pad to which the first wiring pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected, and the first pad is connected. The size of the stub that is a soldered portion of the first pad to which the first wiring pattern is connected to the connector lead is set to the size of the second pad to which the second wiring pattern is connected. Is characterized by smaller than a soldered portion is the size of the stub with Nekutarido.

  The invention according to claim 13 is the electronic component mounting method according to claim 10, 11 or 12, wherein the high-speed signal is a differential transmission system signal.

  According to a fourteenth aspect of the present invention, in the electronic component mounting method according to the tenth aspect, the pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the printed wiring The first pad of the substrate is characterized in that the thickness of the dielectric in the vicinity of the conductor layer is 0.15 mm.

  According to a fifteenth aspect of the present invention, in the electronic component mounting method according to the eleventh aspect, the size of the stub of the first pad to which the first wiring pattern is connected is 0.1 mm. The thickness of the dielectric in the vicinity of the conductor layer with the first pad of the printed wiring board is 0.15 mm.

  According to a sixteenth aspect of the present invention, in the electronic component mounting method according to the twelfth aspect, the pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the first The size of the stub of the first pad to which one wiring pattern is connected is 0.1 mm, and the thickness of the dielectric in the vicinity of the conductor layer where the first pad of the printed wiring board is 0.15 mm. It is characterized by that.

  According to a seventeenth aspect of the present invention, a control apparatus for an image forming apparatus includes the printed wiring board according to any one of the first to ninth aspects.

  According to the present invention, impedance mismatch between the first pad to which the first wiring pattern forming the signal line of the high-speed signal is connected can be suppressed, and the pad group and the connector lead of the connector can be suppressed. The soldering strength at the soldering portion can be sufficiently ensured.

Hereinafter, the present invention will be described based on illustrated embodiments.
<Embodiment 1>
FIG. 1 is a plan view showing a printed wiring board according to Embodiment 1 in which the present invention is applied to a control device of an image forming apparatus (such as a copier or a printer).

  As shown in FIG. 1, a control apparatus for an image forming apparatus such as a copier or a printer includes a printed wiring board 1 as an image processing unit and a printed board 2 as a control unit for the entire apparatus. A device 3 as an image processing unit is provided on the printed wiring board 1, and a device 4 as an overall control unit is provided on the printed board 2. Since the printed wiring boards 1 and 2 adopt a high-speed differential transmission system when sending data from the device 3 to the device 4, they are generally printed wiring boards having four or more layers.

  The device 3 on the printed wiring board 1 is connected to one end side of the wiring pattern 6a as a high-speed differential signal line, and the one end side of the wiring pattern 6b as a high-speed differential signal line is connected to the device 4 on the printed wiring board 2. The other end sides of the wiring patterns 6a and 6b are connected to the connectors 7a and 7b, respectively. When the connectors 7a and 7b are fitted, the high-speed differential signal line of the device 3 on the printed wiring board 1 and the high-speed differential signal line of the device 4 on the printed wiring board 2 are electrically connected. . Further, the wiring patterns 5a and 5b as low-speed signal lines are also connected to the connectors 7a and 7b, and the low-speed signal lines and the high-speed differential signal lines are mixed.

  On the printed wiring boards 1 and 2, as shown in FIG. 2, a pad group 8 for mounting the connectors 7a and 7b is formed. The pads 8a and 8b (first pads) to which the wiring patterns 6a and 6b for the high-speed differential signal line in the pad group 8 are connected are connected to the wiring pattern 5 for the low-speed signal line. The pad width is narrower than the plurality of pads 8c (second pads). In this embodiment, when the connectors 7a and 7b having a pitch of 0.5 mm are soldered to the pad group 8 on the printed wiring boards 1 and 2 via the connector leads, the pad width of the pads 8a and 8b is 0.2 mm. It was. A plurality of pads 8d other than the pads 8a and 8b and the pad 8c are pads for power supply and ground. In the present embodiment, the thickness of the dielectric in the vicinity of the conductor layer with the pad group 8 on the printed wiring boards 1 and 2 is 0.15 mm.

  Thus, by reducing the pad width of the pads 8a and 8b to which the wiring patterns 6a and 6b for the high-speed differential signal lines are connected, the spacing between the pads 8a and 8b is reduced to the wiring pattern 5a for the low-speed signal lines. , 5b is wider than each of the plurality of pads 8c to which the pads are connected, and capacitive coupling between the pads 8a, 8b and the layer (dielectric) of the printed wiring board 1, 2 immediately below the pads 8c is reduced.

  Thus, the difference between the pads 8a and 8b connected to the wiring patterns 6a and 6b for the high-speed differential signal line is larger than the plurality of pads 8c connected to the wiring patterns 5a and 5b for the low-speed signal lines. The dynamic impedance can be increased. Therefore, the differential impedance values of the pads 8a and 8b can be included in the standard of the transmission system used in the printed wiring boards 1 and 2, so that reflection due to impedance mismatching can be suppressed and the waveform quality can be reduced. Can keep good.

  Further, when applied to the control device of the image forming apparatus as in the present embodiment, as described above, the pad 8a, 8b portion to which the wiring patterns 6a, 6b for high-speed differential signal lines are connected is used. By suppressing impedance mismatch, the image signal as a high-speed differential signal is not disturbed, and good image quality can be obtained.

  Further, the pads 8c and 8d other than the pads 8a and 8b in the pad group 8 have a normal pad width wider than the pad width of the pads 8a and 8b, and therefore in these pads 8c and 8d portions. At the soldered portions of the connectors 7a and 7b with the connector leads (not shown), the soldering strength of the connectors 7a and 7b itself is sufficiently secured.

  That is, in the present embodiment, when the pad group 8 having the connector leads of the connectors 7a and 7b and the pads 8a and 8b having a narrow pad width is soldered, the soldering strength is the pad of all the pads on which the connectors 7a and 7b are mounted. Compared with the case where the width is reduced, the strength is increased, and the reliability of the strength by soldering the connector leads of the connectors 7a and 7b and the pad group 8 can be ensured.

In the first embodiment, the number of wiring patterns 6a and 6b for high-speed differential signal lines is two. However, the number of wiring patterns 6a and 6b for high-speed differential signal lines is two or more. Similarly, the pad width of each pad connected is reduced.
<Embodiment 2>
FIG. 3 is a plan view showing a pad group for mounting a connector on a printed wiring board according to Embodiment 2 of the present invention, and FIG. 4 is a plan view showing a state in which the connector is mounted on the pad group. 5 is a cross-sectional view taken along line AA in FIG. In addition, the same code | symbol is attached | subjected to the member which has the same function as Embodiment 1 shown in FIG. 2, and the overlapping description is abbreviate | omitted. Also in this embodiment, the thickness of the dielectric in the vicinity of the conductor layer where the pads are on the printed wiring board is 0.15 mm.

  When the connectors 7a and 7b are mounted on the pad group 8 (pads 8a, 8b, 8c, and 8d) on the printed circuit board, soldering is also applied to the bent portion of the connector lead 9 as shown in FIG. Therefore, the stub 10 is provided in the pad group 8 (pads 8a and 8d in FIG. 5). Therefore, in the present embodiment, the pad widths of the pads 8a and 8b to which the wiring patterns 6a and 6b for the high-speed differential signal lines in the pad group 8 are connected are narrowed (see FIGS. 3 and 4), and The stubs 10 of the pads 8a and 8b, which are the parts to which the connector leads 9 of the surface mounting connectors 7a and 7b are soldered, are reduced (see FIG. 5). In FIG. 5, the stub 10 of the pad 8d has a normal length. By reducing the stubs 10 of the pads 8a and 8b, the length in the longitudinal direction is shorter than the other pads 8c and 8d in the pad group 8, as shown in FIG.

  In the present embodiment, when the connectors 7a and 7b having a pitch of 0.5 mm are soldered to the pad group 8 on the printed wiring board via the connector leads 9, the pad width of the pads 8a and 8b is 0.2 mm. The length of the stub 10 of the pads 8a and 8b was set to 0.1 mm.

  Thus, by reducing the pad width of the pads 8a and 8b to which the wiring patterns 6a and 6b for the high-speed differential signal lines are connected, the spacing between the pads 8a and 8b is reduced to the wiring pattern 5a for the low-speed signal lines. , 5b is wider than each of the plurality of pads 8c to which the pads 8c are connected, and the stubs 10 of the pads 8a, 8b are shortened, whereby the pads 8a, 8b and the printed wiring board layer (dielectric material) ) Can be further reduced.

  Thereby, the differential impedance of the pads 8a and 8b connected to the wiring patterns 6a and 6b for the high-speed differential signal line can be further increased. Accordingly, the differential impedance value of the pads 8a and 8b can be set to the median value (100Ω) of the standard of the transmission method used in this printed wiring board, so that reflection due to impedance mismatching can be suppressed and the waveform can be reduced. Quality can be kept good.

  Further, when applied to the control device of the image forming apparatus as in the present embodiment, as described above, the pad 8a, 8b portion to which the wiring patterns 6a, 6b for high-speed differential signal lines are connected is used. By suppressing impedance mismatch, the image signal as a high-speed differential signal is not disturbed, and good image quality can be obtained.

  Further, the pads (pads 8c) other than the pads 8a and 8b to which the wiring patterns 6a and 6b for the high-speed differential signal lines in the pad group 8 are connected are usually wider than the pad width of the pads 8a and 8b. Therefore, the soldering strength of the connectors 7a and 7b itself is sufficiently secured at the soldered portions of the connectors 7a and 7b with the connector leads 9 at these pad portions.

  Even in this case, it is possible to reduce the capacitive coupling between the pads 8a and 8b and the layer (dielectric) of the printed wiring board immediately below the pads 8a and 8b, and to increase the differential impedance of the pads 8a and 8b. Therefore, the differential impedance values of the pads 8a and 8b can be set within the standard of the transmission system used in the printed wiring board, so that reflection due to impedance mismatching is suppressed and the waveform quality is kept good. be able to. Further, in this case, since all the pads of the pad group 8 have a normal wide pad width, the connectors 7a and 7b themselves are soldered to the connector leads 9 of the connectors 7a and 7b in the respective pad portions. Sufficient soldering strength is ensured.

  In the second embodiment, the number of wiring patterns 6a and 6b for high-speed differential signal lines is two. However, the number of wiring patterns 6a and 6b for high-speed differential signal lines is two or more. Similarly, the pad width of each pad connected is reduced, and the stub 10 is reduced.

  In the second embodiment, the pad widths of the pads 8a and 8b to which the wiring patterns 6a and 6b for high-speed differential signal lines are connected are narrowed, and the stubs 10 of the pads 8a and 8b are reduced. However, the stubs 10 of the pads 8a and 8b may be reduced without reducing the pad width of the pads 8a and 8b.

1 is a plan view showing a printed wiring board applied to a control device of an image forming apparatus according to Embodiment 1 of the present invention. The top view which shows the pad group for mounting the connector on the printed wiring board which concerns on Embodiment 1 of this invention. The top view which shows the pad group for mounting the connector on the printed wiring board which concerns on Embodiment 2 of this invention. The top view which shows the state in which the connector is mounted on the pad group in Embodiment 2 of this invention. AA line sectional view of Drawing 4. The top view which shows the printed wiring board in which the wiring pattern as a low-speed signal line and the wiring pattern as a high-speed differential signal line are mixed in the prior art example, and are connected via the connector. Sectional drawing of the printed wiring board in which the wiring pattern as a high-speed differential signal line is formed on the surface in the prior art example.

Explanation of symbols

1, 2 Printed wiring board 3, 4 Device 5a, 5b Wiring pattern (second wiring pattern)
6a, 6b wiring pattern (first wiring pattern)
7a, 7b connector 8 pad group 8a, 8b pad (first pad)
8c pad (second pad)
8d pad 9 connector lead 10 stub

Claims (17)

A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad A printed wiring board having a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group;
Making the pad width of the first pad to which the first wiring pattern is connected narrower than the pad width of the second pad to which the second wiring pattern is connected;
A printed wiring board characterized by that. A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad A printed wiring board having a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group;
The size of the stub, which is a soldered portion of the first pad to which the first wiring pattern is connected, to the connector lead, and the connector of the second pad to which the second wiring pattern is connected Make it smaller than the size of the stub, which is the soldering part with the lead,
A printed wiring board characterized by that. A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad A printed wiring board having a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group;
The pad width of the first pad to which the first wiring pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected, and the first wiring pattern is The size of the stub that is a soldered portion of the first pad to be connected to the connector lead is determined by the soldered portion of the second pad to which the second wiring pattern is connected to the connector lead. Smaller than the size of a stub,
A printed wiring board characterized by that. The high-speed signal is a differential transmission system signal.
The printed wiring board according to claim 1, 2, or 3. The pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the thickness of the dielectric in the vicinity of the conductor layer where the first pad of the printed wiring board is 0.15 mm. did,
The printed wiring board according to claim 1. The size of the stub of the first pad to which the first wiring pattern is connected is set to 0.1 mm, and the thickness of the dielectric in the vicinity of the conductor layer on which the first pad of the printed wiring board is located is set to 0. 15mm,
The printed wiring board according to claim 2. The pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, the size of the stub of the first pad to which the first wiring pattern is connected is 0.1 mm, The thickness of the dielectric in the vicinity of the conductor layer with the first pad of the printed wiring board was 0.15 mm,
The printed wiring board according to claim 3. Input / output devices are connected to the first wiring pattern and the second wiring pattern,
The printed wiring board according to claim 1, 2, or 3. The layer structure of the substrate consists of at least four layers,
The printed wiring board according to claim 1, 2, or 3. A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad In a mounting method of an electronic component in which a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group is mounted on a printed wiring board,
The pad width of the first pad to which the first wiring pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected;
An electronic component mounting method characterized by the above. A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad In a mounting method of an electronic component in which a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group is mounted on a printed wiring board,
The size of the stub, which is a soldered portion of the first pad to which the first wiring pattern is connected, to the connector lead, and the connector of the second pad to which the second wiring pattern is connected Make it smaller than the size of the stub, which is the soldering part with the lead,
An electronic component mounting method characterized by the above. A pad group on which a connector for surface mounting is mounted by soldering with a connector lead; a first wiring pattern for forming a signal line of a high-speed signal connected to the first pad in the pad group; and the pad In a mounting method of an electronic component in which a second wiring pattern that forms a signal line other than the high-speed signal connected to a second pad in the group is mounted on a printed wiring board,
The pad width of the first pad to which the first wiring pattern is connected is made narrower than the pad width of the second pad to which the second wiring pattern is connected, and the first wiring pattern The size of the stub, which is a soldered portion of the first pad to which the second wiring pattern is connected, is soldered to the connector lead of the second pad to which the second wiring pattern is connected. Smaller than the size of the stub,
An electronic component mounting method characterized by the above. The high-speed signal is a differential transmission system signal.
The electronic component mounting method according to claim 10, wherein the electronic component is mounted. The pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, and the thickness of the dielectric in the vicinity of the conductor layer where the first pad of the printed wiring board is 0.15 mm. did,
The electronic component mounting method according to claim 10. The size of the stub of the first pad to which the first wiring pattern is connected is 0.1 mm, and the thickness of the dielectric in the vicinity of the conductor layer on which the first pad of the printed wiring board is located is 0. .15mm,
12. The electronic component mounting method according to claim 11, wherein the electronic component is mounted. The pad width of the first pad to which the first wiring pattern is connected is 0.2 mm, the size of the stub of the first pad to which the first wiring pattern is connected is 0.1 mm, The thickness of the dielectric in the vicinity of the conductor layer with the first pad of the printed wiring board was 0.15 mm,
13. The electronic component mounting method according to claim 12, wherein the electronic component is mounted. The printed wiring board according to any one of claims 1 to 9, comprising:
A control device for an image forming apparatus.

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