JP6524826B2 - Multi-core cable connector and cable with connector - Google Patents

Description

  The present invention relates to a multicore cable connector and a cable with a connector.

  Conventionally, a connector-equipped cable (direct attach cable, DAC) is known in which a multicore cable connector is provided at the end of a multicore cable provided with a plurality of differential signal transmission cables for transmitting differential signals.

  The multi-core cable connector used for the cable with connector includes a substrate, a plurality of pairs of transmission lines which are formed of the wiring patterns formed on the substrate and which transmit differential signals, and a plurality of terminals electrically connected to the other end of the transmission line. And a pair of contact pads.

  The contact pads are formed in alignment at the end of the substrate opposite to the cable connection side, and are electrically connected to the electrodes of the receiving connector to be connected at the time of connector connection.

  In addition, there exists patent document 1 as prior art literature information relevant to the invention of this application.

Patent No. 4673191

  By the way, the size of the contact pad is defined by a standard or the like, and the contact pad is generally formed to be wider than the transmission line.

  Therefore, at the contact pad, the characteristic impedance (differential impedance) is lower than that of the transmission line, and impedance mismatching occurs between the transmission line and the contact pad, leading to deterioration of signal quality. is there.

  Also, in general, in multi-core cable connectors, the transmission lines of each pair are formed such that the line lengths are equal to each other (equal length wiring). There is a problem that crosstalk becomes large (a peak is generated in the crosstalk waveform).

  An object of the present invention is to provide a multicore cable connector and a cable with a connector capable of suppressing impedance mismatching at a contact pad and suppressing deterioration of crosstalk characteristics due to resonance between pairs.

  The present invention is a multicore cable connector provided at an end portion of a multicore cable provided with a plurality of differential signal transmission cables for transmitting differential signals, for the purpose of solving the above-mentioned problems, comprising: a substrate; The differential signal transmission cable is electrically connected to one end of the substrate, and a plurality of pairs of transmission lines for transmitting differential signals, and the other end of the plurality of transmission lines are formed on the substrate. Pairs of contact pads which are electrically connected to each other and which are electrically connected to the electrodes of the receiving connector to be connected at the time of connector connection, the other ends of the plurality of transmission lines and the plurality of contacts And a plurality of pairs of high impedance lines respectively provided between the pads and having a differential impedance higher than that of the transmission lines, at least corresponding to the pair of adjacent transmission lines. Impedance lines are formed in different line length, to provide a multi-core cable connector.

  In addition, the present invention has a multicore cable provided with a plurality of differential signal transmission cables for transmitting differential signals, and is provided at at least one end of the multicore cable, for the purpose of solving the above problems. A multi-core cable connector, wherein the multi-core cable connector is formed on a substrate and the substrate, the differential signal transmission cable is electrically connected to one end, and A plurality of pairs of transmission lines for transmitting motion signals, and the other end of the plurality of pairs of transmission lines formed on the substrate, are electrically connected to the other ends of the plurality of pairs of transmission lines, and are electrically connected Between a plurality of contact pads connected to each other, the other end of the plurality of transmission lines and the plurality of pairs of contact pads, and a differential impedance higher than the transmission lines And a plurality of pairs of high-impedance line having at least said high impedance line corresponding to a pair of the transmission lines adjacent, are formed in different line length, to provide a connector with cables.

  According to the present invention, it is possible to provide a multicore cable connector and a cable with a connector capable of suppressing impedance mismatch at contact pads and suppressing deterioration of crosstalk characteristics due to resonance between pairs.

(A) is a schematic block diagram of a connector-equipped cable provided with a multi-core cable connector according to an embodiment of the present invention, and (b) is an enlarged view of part A thereof. It is sectional drawing at the time of connecting with a multi-core cable connector to the receiving side connector. (A), (b) is a figure explaining the simulation result of cross talk between pairs.

Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

(Overall structure of multi-core cable connector)
Fig.1 (a) is a schematic block diagram of the cable with a connector provided with the multicore cable connector which concerns on this Embodiment, (b) is the A section enlarged view.

  As shown in FIGS. 1A and 1B, the multicore cable connector 1 is provided at an end of a multicore cable 3 provided with a plurality of differential signal transmission cables 2 for transmitting differential signals. . A connector-equipped cable 100 according to the present embodiment is provided with the multi-core cable connector 1 at at least one end of the multi-core cable 3.

  The differential signal transmission cable 2 includes a pair of signal conductors 2a, an insulator (not shown) covering the signal conductors 2a collectively or individually, and a shield conductor 2b provided on the outer periphery of the insulator. And a sheath 2c provided on the outer periphery of the shield conductor 2b. Here, the case where the differential signal transmitted through the signal conductor 2a is 25 Gb / s (gigabits per second) will be described.

  The multi-core cable 3 is configured by putting together a plurality of differential signal transmission cables 2 and covering a jacket 3 a around the same. Here, in order to enable transmission and reception of four channels, a multicore cable 3 provided with eight differential signal transmission cables 2 was used. In FIG. 1A, only the four differential signal transmission cables 2 connected to the front surface S of the substrate 4 are shown, but four differential signal transmission cables are also provided on the back surface of the substrate 4 2 is connected.

  The multi-core cable connector 1 includes a substrate 4, a plurality of pairs of transmission lines 5 for transmitting differential signals, and a plurality of pairs of contact pads 6 electrically connected to the end of the transmission lines 5. .

  For example, a multilayer substrate using FR 4 (Flame Retardant Type 4) as a dielectric can be used as the substrate 4. The transmission line 5 and the contact pad 6 are formed of a wiring pattern (copper foil) formed on the substrate 4. Here, the substrate 4 using a dielectric whose relative dielectric constant εr at 10 GHz is 3.6 is used.

  In the present embodiment, eight pairs of transmission lines 5 and eight pairs of contact pads 6 are formed on the substrate 4 so as to correspond to eight differential signal transmission cables 2. Although four pairs of transmission lines 5 and four pairs of contact pads 6 are formed on the surface S of the substrate 4, four pairs of transmission lines 5 and four pairs of contact pads 6 are also formed on the back surface of the substrate 4. It is formed.

  At one end of the transmission line 5, a cable-side pad 7 for connecting the signal conductor 2 a of the differential signal transmission cable 2 is formed. The signal conductor 2a is electrically connected to one end of the transmission line 5 by fixing the signal conductor 2a to the cable-side pad 7 by soldering or the like.

  Further, a cable-side ground pad 8 for connecting the shield conductor 2b of the differential signal transmission cable 2 is formed at an end of the substrate 4 at one end side (cable connection side) than the cable-side pad 7 . By fixing the shield conductor 2b to the cable side ground pad 8 by soldering or the like, the shield conductor 2b and the ground pattern (not shown) of the substrate 4 are electrically connected. The ground pattern is formed, for example, in the inner layer of the substrate 4 formed of a multilayer substrate, and the ground pattern and the cable side ground pad 8 are electrically connected through the through holes. In FIG. 1A, the cable-side ground pad 8 is formed so as to be common to the two differential signal transmission cables 2, but the cable-side ground pads are individually provided for the differential signal transmission cables 2. 8 may be formed.

  The contact pad 6 is electrically connected to the other end of the transmission line 2 (the end opposite to the cable-side pad 7), and aligned with the other end of the substrate 4 (the end opposite to the cable connection side) It is formed. That is, at the other end of the substrate 4, the contact pads 6 are formed in alignment on the front and back surfaces of the substrate 4 to form a card edge connector. Reference numeral 6 a is a ground connection contact pad electrically connected to the ground pattern of the substrate 4. The ground connection contact pad 6a is a part of the contact pad 6, and is disposed so as to sandwich the pair of contact pads 6 for signal transmission in the alignment direction.

  As shown in FIG. 2, when connecting the multi-core cable connector 1 with a connector, the other end of the substrate 4 is inserted into the receiving connector 21 to be connected. At this time, the communication pad (not shown) in which the contact pad 6 formed at the other end of the substrate 4 is electrically connected to the electrode 22 of the receiving connector 21 and the multicore cable 3 and the receiving connector 21 are mounted. Are electrically connected via the multicore cable connector 1 and the receiving connector 21.

(Description of high impedance line)
Referring back to FIGS. 1A and 1B, in the multicore cable connector 1 according to the present embodiment, the multicore cable connector 1 is provided between the other end of the plurality of pairs of transmission lines 5 and the plurality of pairs of contact pads 6, A plurality of pairs of high impedance lines 9 having a differential impedance (characteristic impedance of differential wiring) higher than that of the transmission line 5 are provided.

  The contact pad 6 is formed wider than the line width of the transmission line 5, and the distance between the adjacent contact pads 6 is also shorter, so the differential impedance is lower than that of the transmission line 5. In the present embodiment, the high impedance line 9 having a high differential impedance is provided in the immediate vicinity of the contact pad 6 to offset the drop in the differential impedance at the contact pad 6, thereby reducing the impedance between the transmission line 5 and the contact pad 6. Inconsistencies are suppressed.

  Here, the width W1 of the contact pad 6 including the ground connection contact pad 6a is 0.50 to 0.63 mm, and the arrangement pitch P of the contact pads 6 in the alignment direction is 0.8 mm. Further, the distance W2 from the center of the leftmost ground connection contact pad 6a in FIG. 1A to the center of the rightmost ground connection contact pad 6a is 14.40 mm. Also, the line width W3 of the transmission line 5 is 0.2 mm.

  Furthermore, in the present embodiment, high impedance lines 9 corresponding to at least a pair of adjacent transmission lines 5 are formed to have different line lengths L.

  In the conventional multi-core cable connector, it is general that the transmission line length of each pair of transmission lines is configured to be equal, but in this manner, the transmission line lengths of each pair are set to be the same. If so, the resonant frequency in each pair will be the same, and crosstalk will increase at a particular frequency.

  In the present embodiment, by making the line lengths L of at least the pair of adjacent high impedance lines 9 different, the resonance frequency is made different between adjacent pairs where the influence of crosstalk is the largest. It is suppressing that the cross talk becomes large by the frequency. In the present embodiment, the combined line lengths of the transmission line 5 and the high impedance line 9 may be configured to be equal in each pair.

  In the present embodiment, the plurality of pairs of high impedance lines 9 are formed to have the same line width W4, and the line lengths L are made different so that the resonance frequencies of the pairs are made different. The line width W4 of the high impedance line 9 is set smaller than the line width W3 of the transmission line 5. Here, considering that the differential impedance of the transmission line 5 is 100Ω and the differential impedance of the contact pad 6 is about 90Ω, the line width W4 is 0.1 mm, and the differential impedance of the high impedance line 9 is 140Ω. Set to By providing the high impedance line 9, it is possible to improve the differential impedance of the contact pad 6 to about 95 Ω and to suppress the impedance mismatch between the transmission line 5 and the contact pad 6.

  It is also conceivable to make the resonance frequency of each pair different by making the line length L of the high impedance line 9 constant and making the line width W 4 different for each pair. However, since there is a limit to narrowing the line width W4, it is difficult to make the resonance frequency of each pair different enough to sufficiently suppress crosstalk due to the difference in the line width W4, and the line width If W4 is made different, there is a possibility that manufacturing errors may be separated in each pair, and it may be considered that the effect of crosstalk suppression can not be sufficiently obtained. The line width W4 of the high impedance line 9 is preferably 0.1 mm or more from the viewpoint of reliability.

  That is, by setting the high impedance line 9 to have a fixed line width W4 and making the line length L different for each pair, it is possible to easily make the resonance frequencies of each pair different, and the error in manufacturing It is less likely to be affected.

  The line lengths L of the high impedance lines 9 may be different at least in adjacent pairs, and the line lengths L of the high impedance lines 9 which are not adjacent to each other may be set equal. Further, the line length of the high impedance line 9 may be made different for each pair, and the resonance frequency may be made different for each pair.

  In this embodiment, the line length L of each pair of high impedance lines 9 is set to 500 μm, 300 μm, 500 μm, and 300 μm from the left side to the right side in FIG. Compared to the technology, the peak value of the crosstalk waveform could be reduced by about 3 dB. In addition, even when the line length L of each pair of high impedance lines 9 is set to 300 μm, 400 μm, 500 μm, and 600 μm from the left side to the right side in FIG. Thus, the peak value of the crosstalk waveform could be reduced by about 3 dB.

  When the line length L of the high impedance line 9 is shortened to less than 300 μm, the effect of suppressing the impedance mismatch between the transmission line 5 and the contact pad 6 may not be obtained sufficiently. If the line length L of the high impedance line 9 is longer than 600 μm, impedance mismatch between the high impedance line 9 and the transmission line 5 or between the high impedance line 9 and the contact pad 6 becomes a problem, and the signal quality is degraded. There is a risk of

  Therefore, in the present embodiment, it can be said that it is desirable to set the line length L of the high impedance line 9 to 300 μm or more and 600 μm or less. Here, in the present embodiment, since the differential signal to be transmitted is 25 Gb / s (center frequency is 12.5 GHz) and the relative permittivity 率 r of the substrate 4 is 3.6, the wavelength shortening effect by the substrate 4 The wavelength in consideration of is about 12.6 mm. From this, it is preferable that the line length L of the high impedance line 9 is 2% or more and 5% or less of the wavelength corresponding to the center frequency of the differential signal to be transmitted (the wavelength considering the wavelength shortening effect by the substrate 4). It can be said.

  In addition, if the difference between the line lengths L of the pairs of high impedance lines 9 adjacent to each other is too small, it is considered that the resonance frequency becomes equal between adjacent pairs, and the effect of suppressing the peak value of the crosstalk waveform can not be sufficiently obtained. .

  As described above, it has been confirmed that the peak value of the crosstalk waveform can be suppressed by setting the difference between the line lengths L of at least the pair of adjacent high impedance lines 9 to 100 μm or more. It is desirable that the difference between the line lengths L of the pair be at least 1% or more and 3% or less of the wavelength corresponding to the center frequency of the differential signal to be transmitted. When the difference between the line lengths L of the pair of high impedance lines 9 adjacent to each other is made larger than 3%, the line lengths L of all the high impedance lines 9 are 2% of the wavelength corresponding to the center frequency of the differential signal to be transmitted. It can not be in the range of 5% or less. Further, as described above, since it is desirable that the line length L of the high impedance line 9 be 300 μm or more from the viewpoint of suppressing impedance mismatch, the difference between the line lengths L of the pair of adjacent high impedance lines 9 is It can be said that 30% or more of the line length of the shortest high impedance line 9 is desirable.

  Here, the results of experiments conducted to confirm the effects of the present embodiment will be described.

  As shown in FIG. 3A, from lane 1 (first pair) one end is connected to the signal input and the other end is connected to the 50Ω termination, one end is connected to the 50Ω termination and the other end is connected to the signal output The crosstalk to lane 2 (second pair) was determined by measurement. Here, the line length L of the high impedance line 9 of lane 1 is 500 μm, and the line length L of the high impedance line 9 of lane 2 is 300 μm. Further, the line width W4 of the high impedance line 9 in both lanes is 0.1 mm, and the differential impedance of the high impedance line 9 is 140 Ω.

  The same experiment was performed on the conventional example without the high impedance line 9. The results are summarized in FIG. 3 (b).

  As shown in FIG. 3B, in the embodiment (solid line) in which high impedance lines 9 of different line lengths L are provided, the frequency is 7 to 8 GHz as compared with the conventional example (broken line) in which the high impedance line 9 is not provided. It can be seen that the peak value of the crosstalk waveform that occurs in is improved by about 3 dB. As described above, by providing the high impedance lines 9 having different line lengths L, it is possible to suppress the deterioration of the crosstalk characteristic due to the resonance between the pairs.

(Operation and effect of the embodiment)
As described above, in the present embodiment, a plurality of pairs each provided between the other end of the plurality of pairs of transmission lines 5 and the plurality of pairs of contact pads 6 and having a differential impedance higher than that of the transmission lines 5 The high impedance lines 9 at least corresponding to the pair of adjacent transmission lines 5 are formed to have different line lengths L.

  By providing the high impedance line 9 in the immediate vicinity of the contact pad 6, it is possible to offset the drop in differential impedance at the contact pad 6 and to suppress the impedance mismatch between the transmission line 5 and the contact pad 6. As a result, it is possible to suppress loss such as reflection due to impedance mismatch and to suppress deterioration of signal quality.

  Further, by making the line lengths L of the high impedance lines 9 different between at least adjacent pairs, it becomes possible to shift the resonance frequency in the adjacent pairs where the influence of crosstalk is the largest, and crosstalk is large at a specific frequency. It becomes possible to suppress the peak of the crosstalk waveform. That is, according to the present embodiment, it is possible to suppress the deterioration of the crosstalk characteristic due to the resonance between the pair.

(Summary of the embodiment)
Next, technical ideas to be understood from the embodiments described above will be described by using the reference numerals and the like in the embodiments. However, each reference numeral or the like in the following description does not limit the constituent elements in the claims to the members or the like specifically shown in the embodiments.

[1] A multicore cable connector (1) provided at an end of a multicore cable (3) comprising a plurality of differential signal transmission cables (2) for transmitting differential signals, the substrate (4) and A plurality of pairs of transmission lines (5) formed on the substrate (4), the differential signal transmission cable (2) being electrically connected to one end, and transmitting differential signals; and the substrate (4) And a plurality of electrodes electrically connected to the other end of the plurality of pairs of transmission lines (5) and electrically connected to electrodes (22) of the receiving connector (21) to be connected when the connectors are connected A difference higher than the transmission line (5) provided between the pair of contact pads (6), the other end of the plurality of transmission lines (5), and the plurality of pairs of contact pads (6) Pairs of high impedance lines (9) with dynamic impedance, Wherein at least said high impedance line corresponding to a pair of said transmission line adjacent (5) (9) is formed in a different line length, multi-conductor cable connector (1).

[2] The multicore cable connector (1) according to [1], wherein the plurality of pairs of high impedance lines (9) are formed to have the same line width.

[3] The multicore cable connector (1) according to [1] or [2], wherein the plurality of pairs of high impedance lines (9) are formed to have different line lengths for each pair.

[4] Any one of [1] to [3], wherein the high impedance line (9) is formed to have a line length of 2% to 5% of the wavelength corresponding to the center frequency of the differential signal to be transmitted The multicore cable connector (1) according to Item.

[5] to [4], wherein the difference in line length between the pair of high impedance lines (9) adjacent to each other is 1% or more and 3% or less of the wavelength corresponding to the center frequency of the differential signal to be transmitted The multicore cable connector (1) according to any one of the above.

[6] A multicore cable (3) including a plurality of differential signal transmission cables (2) for transmitting differential signals, and a multicore cable provided at at least one end of the multicore cable (3) A connector-equipped cable (100) comprising a connector (1), wherein the multi-core cable connector (1) is formed on a substrate (4) and the substrate (4) and the differential signal at one end A transmission cable (2) is electrically connected and is formed on a plurality of pairs of transmission lines (5) for transmitting differential signals, and the substrate (4), and the other end of the plurality of pairs of transmission lines (5) And a plurality of pairs of contact pads (6) electrically connected to the electrodes (22) of the receiving connector (21) to be connected at the time of connector connection, and the plurality of pairs of transmission lines ( 5) the other end and the pairs of contact pads (6) And a plurality of pairs of high impedance lines (9) each having a differential impedance higher than that of the transmission line (5), and at least corresponding to the pair of adjacent transmission lines (5) Connectorized cable (100), wherein said high impedance lines (9) are formed in different line lengths.

  As mentioned above, although embodiment of this invention was described, embodiment described above does not limit the invention which concerns on a claim. In addition, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  The present invention can be appropriately modified and implemented without departing from the scope of the invention.

  For example, although not mentioned in the above embodiment, the transmission line 5 on the receiving side of the multicore cable connector 1 may be provided with a compensation circuit that performs compensation and amplification of the received differential signal.

Reference Signs List 1 multicore cable connector 2 differential signal transmission cable 3 multicore cable 4 board 5 transmission line 6 contact pad 9 high impedance line 21 receiving side connector 22 electrode 100 cable with connector

Claims (5)

A multicore cable connector provided at an end of a multicore cable comprising a plurality of differential signal transmission cables for transmitting differential signals, comprising:
A substrate,
A plurality of pairs of transmission lines formed on the substrate, the differential signal transmission cable electrically connected to one end, and transmitting differential signals;
A plurality of pairs of contact pads formed on the substrate, electrically connected to the other end of the plurality of pairs of transmission lines, and electrically connected to electrodes of a receiving connector to be connected at the time of connector connection;
A plurality of pairs of high impedance lines respectively provided between the other ends of the plurality of pairs of transmission lines and the plurality of contact pads and having a differential impedance higher than that of the transmission lines;
At least the high impedance lines corresponding to the pair of adjacent transmission lines are formed in different line lengths ,
The difference between the line lengths of the pair of high impedance lines adjacent to each other is 1% or more and 3% or less of the wavelength corresponding to the center frequency of the differential signal to be transmitted.
Multicore cable connector. The plurality of pairs of high impedance lines are formed in the same line width,
The multicore cable connector according to claim 1. The plurality of pairs of high impedance lines are formed in different line lengths for each pair,
A multicore cable connector according to claim 1 or 2. The high impedance line is formed to have a line length of 2% to 5% of the wavelength corresponding to the center frequency of the differential signal to be transmitted.
The multicore cable connector according to any one of claims 1 to 3. A cable with a connector comprising: a multicore cable comprising a plurality of differential signal transmission cables for transmitting differential signals; and a multicore cable connector provided at at least one end of the multicore cable ,
The multicore cable connector is
A substrate,
A plurality of pairs of transmission lines formed on the substrate, the differential signal transmission cable electrically connected to one end, and transmitting differential signals;
A plurality of pairs of contact pads formed on the substrate, electrically connected to the other end of the plurality of pairs of transmission lines, and electrically connected to electrodes of a receiving connector to be connected at the time of connector connection;
A plurality of pairs of high impedance lines respectively provided between the other ends of the plurality of pairs of transmission lines and the plurality of contact pads and having a differential impedance higher than that of the transmission lines;
At least the high impedance lines corresponding to the pair of adjacent transmission lines are formed in different line lengths ,
The difference between the line lengths of the pair of high impedance lines adjacent to each other is 1% or more and 3% or less of the wavelength corresponding to the center frequency of the differential signal to be transmitted.
Cable with connector.

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