CN115087189A - Circuit board structure and layout structure thereof - Google Patents

Circuit board structure and layout structure thereof Download PDF

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Publication number
CN115087189A
CN115087189A CN202110282035.9A CN202110282035A CN115087189A CN 115087189 A CN115087189 A CN 115087189A CN 202110282035 A CN202110282035 A CN 202110282035A CN 115087189 A CN115087189 A CN 115087189A
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China
Prior art keywords
circuit board
pad
impedance
disposed
adjusting wire
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CN202110282035.9A
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Chinese (zh)
Inventor
张哲荣
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HTC Corp
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HTC Corp
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Priority to CN202110282035.9A priority Critical patent/CN115087189A/en
Publication of CN115087189A publication Critical patent/CN115087189A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0237—High frequency adaptations
    • H05K1/025—Impedance arrangements, e.g. impedance matching, reduction of parasitic impedance
    • H05K1/0253—Impedance adaptations of transmission lines by special lay-out of power planes, e.g. providing openings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09218—Conductive traces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Structure Of Printed Boards (AREA)

Abstract

The invention provides a circuit board structure and a layout structure thereof. The layout structure comprises at least one signal transmission line, at least one welding pad and at least one impedance adjusting lead. The signal transmission line, the welding pad and the impedance adjusting lead are arranged on the first circuit board. The impedance adjusting wire is electrically connected between the signal transmission line and the bonding pad. The impedance adjusting wire is arranged along the periphery of the welding pad and at least partially surrounds the welding pad.

Description

Circuit board structure and layout structure thereof
Technical Field
The present invention relates to a circuit board structure and a layout structure thereof, and more particularly, to a circuit board structure and a layout structure thereof capable of reducing signal reflection.
Background
In printed circuit board designs, electrical connections between different circuit boards are often made through pads to connections, such as conductive vias, in order to allow signals to be transmitted between the circuit boards at different heights. However, the pads often have a relatively large surface area and provide a relatively low impedance relative to the transmission line. Therefore, the signal transmission path formed by the transmission line and the bonding pad generates impedance discontinuity, which causes reflection phenomenon in the signal transmission process and reduces the quality of signal transmission.
Disclosure of Invention
The invention provides a circuit board structure and a layout structure thereof, which can reduce the reflection phenomenon during signal transmission.
The circuit board layout structure comprises at least one signal transmission line, at least one welding pad and at least one impedance adjusting lead. The signal transmission line, the welding pad and the impedance adjusting lead are arranged on the first circuit board. The impedance adjusting wire is electrically connected between the signal transmission line and the bonding pad. The impedance adjusting wire is arranged along the periphery of the welding pad and at least partially surrounds the welding pad.
The circuit board structure comprises a first circuit board and a second circuit board. The first circuit board has at least one signal transmission line, at least one bonding pad and at least one impedance adjusting wire. The impedance adjusting wire is electrically connected between the signal transmission line and the bonding pad. The impedance adjusting wire is arranged along the periphery of the welding pad and at least partially surrounds the welding pad. A second circuit board electrically connected to the second circuit board through at least one connection structure.
According to the above, the present invention is electrically connected between the signal transmission line and the pad by providing the impedance adjusting wire. The impedance adjusting wire is arranged along the periphery of the welding pad and at least partially surrounds the welding pad. The impedance discontinuity phenomenon generated in the signal transmission process can be effectively reduced, and the quality of signal transmission can be effectively improved.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG. 1 is a schematic diagram of a circuit board layout structure according to an embodiment of the invention;
fig. 2A and 2B are schematic diagrams respectively illustrating different implementations of a layout structure of an embodiment of the present invention;
FIG. 3 shows a schematic diagram of another implementation of a layout structure of an embodiment of the invention;
FIG. 4 is a Time Domain Reflectometry (TDR) waveform measured by a layout structure according to an embodiment of the present invention;
FIG. 5 shows a schematic diagram of a circuit board structure according to an embodiment of the invention;
fig. 6 is a schematic diagram illustrating a transmission structure of a high-speed transmission interface according to an embodiment of the present invention.
Description of the reference numerals
100. 210, 300: a layout structure;
110. 510, 520: a circuit board;
111. 211-1, 211-2, 221-1, 221-2, 311, 5111, 611, 612, 631, 632: a pad;
112. 212-1, 212-2, 222-1, 222-2, 312: an impedance adjustment wire;
113. 313: a signal transmission line;
410. 420, 430: a curve;
SPC: specification;
500: a circuit board structure;
IC1, IC 2: an integrated circuit;
VIA, 621, 622: a conductive via;
l11: self-induction;
l12: mutual inductance;
c11: self-contained;
c22: mutual compatibility.
Detailed Description
Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a circuit board layout structure according to an embodiment of the invention. The layout structure 100 is disposed on a circuit board 110. The layout structure 100 includes a pad 111, an impedance adjustment wire 112, and a signal transmission line 113. The signal transmission line 113 is electrically connected to one end of the impedance adjustment wire 112, and the other end of the impedance adjustment wire 112 is electrically connected to the pad 111. In the present embodiment, the pad 111 has a relatively large charge transfer surface and provides a first impedance. The impedance adjustment wires 112 disposed in the pads 111 and the signal transmission lines 113 have relatively small charge transfer surfaces and provide a second impedance. Wherein the second impedance is greater than the first impedance.
In the present embodiment, the signal transmission line 113 is used for transmitting an electrical signal. The layout structure 100 improves the continuity of the impedance change between the signal transmission line 113 and the pad 111 by disposing the impedance adjusting wire 112 between the signal transmission line 113 and the pad 111 and by providing a second impedance, which is relatively larger than the first impedance provided by the pad 111, by the impedance adjusting wire 112, so as to effectively reduce the signal reflection phenomenon that may occur during the transmission of the electrical signal.
It should be noted that, in the present embodiment, the impedance adjusting wires 112 may be disposed along the periphery of the bonding pad 111. The shape of the pad 111 may be polygonal or circular. The impedance adjusting wires 112 may be arranged around the pad 111 in a polygonal or circular shape and have a distance from the pad 111 to surround the pad 111. In fig. 1, the impedance adjusting wire 112 may partially surround the pad 111, for example, surround the pad 111 for 1/4 circumferences.
In addition, in the present embodiment, the pads 111 and the impedance adjusting wires 112 may be disposed on the same surface of the circuit board 110. In other embodiments of the present invention, the bonding pads 111 and the impedance adjusting wires 112 may be disposed on different surfaces of the circuit board 110.
Incidentally, in the present embodiment, the bonding pad 111 can be electrically connected to a connection structure and electrically connected to another circuit board through the connection structure. The connection structure may be formed by any form of conductive VIAs (VIA).
Referring to fig. 2A and 2B, fig. 2A and 2B respectively show schematic diagrams of different embodiments of a layout structure according to an embodiment of the invention. In FIG. 2A, the layout structure 210 includes pads 211-1, 211-2 and impedance adjusting wires 212-1, 212-2. The pads 211-1, 211-2 and the impedance-adjusting wires 212-1, 212-2 are disposed on the same surface of the circuit board. One end of the impedance-adjusting wire 212-1 is electrically connected to the pad 211-1, and the other end of the impedance-adjusting wire 212-1 is used to connect to the first signal transmission line. One end of the impedance-adjusting wire 212-2 is electrically connected to the pad 211-2, and the other end of the impedance-adjusting wire 212-2 is used to connect to a second signal transmission line. The first signal transmission line and the second signal transmission line can respectively transmit and receive two electric signals which are differential signals.
In addition, the impedance adjusting wire 212-1 is disposed around the pad 211-1 with a first distance from the pad 211-1. In the embodiment of fig. 2A, the impedance adjusting wire 212-1 surrounds the pad 211-1 for 1/2 circumferences. In another aspect, the impedance adjusting wire 212-2 surrounds the periphery of the pad 211-2 and is disposed with a second distance from the periphery of the pad 211-2. In the embodiment of fig. 2A, the impedance adjusting wire 212-2 may surround the pad 211-2 by 1/2 circumferences. The first spacing distance and the second spacing distance may be the same or different, and there is no fixed limit.
In FIG. 2B, the layout structure 220 includes pads 221-1 and 221-2 and impedance adjustment wires 222-1 and 222-2. The pads 221-1, 221-2 and the impedance adjustment wires 222-1, 222-2 may also be disposed on the same surface of the circuit board. One end of the impedance-adjusting wire 222-1 is electrically connected to the pad 221-1, and the other end of the impedance-adjusting wire 222-1 is used to connect to the first signal transmission line. One end of the impedance-adjusting wire 222-2 is electrically connected to the pad 221-2, and the other end of the impedance-adjusting wire 222-2 is used for connecting to a second signal transmission line. The first signal transmission line and the second signal transmission line can respectively transmit and receive two electric signals which are differential signals.
In addition, the impedance adjusting wire 222-1 is disposed around the pad 221-1 with a first distance from the pad 221-1. In the embodiment of fig. 2B, the impedance-adjusting wire 222-1 surrounds the pad 221-1 for 1 circumference. On the other hand, the impedance adjusting wire 222-2 surrounds the periphery of the pad 221-2 and is disposed with a second distance from the periphery of the pad 221-2. In the embodiment of fig. 2B, the impedance adjusting wire 222-2 may also be up to 1 circumference around the pad 221-2. Similarly, in the present embodiment, the first and second spacing distances may be the same or different, and are not limited to the fixed values.
Referring to fig. 3, fig. 3 is a schematic diagram illustrating another layout structure according to an embodiment of the invention. The layout structure 300 includes a pad 311, an impedance adjustment wire 312, and a signal transmission line 313. In this embodiment, the pads 311 and the impedance adjusting wires 312 may be disposed on different surfaces of the circuit board.
Based on the pads 311 and the impedance adjusting wires 312 disposed on different surfaces of the circuit board, the impedance adjusting wires 312 may be laid out according to a vertical projection of the contour of the pads 311 on the second surface of the circuit board. In the present embodiment, the impedance adjusting conductive line 312 may at least partially overlap with the contour of the pad 311. The length of the impedance adjustment wire 312 may be 1/4, 1/2, 3/4 of the circumference of the pad 311 or substantially equal to the circumference of the pad 311.
By the layout method of the present embodiment, the layout area required by the impedance adjusting wires 312 and the pads 311 can be effectively reduced.
Incidentally, in the present embodiment, the impedance adjusting wires 312 and the signal transmission lines 313 may be disposed on the same surface of the circuit board or may be disposed on different surfaces of the circuit board, respectively, without specific limitation. When the impedance-adjusting conductive line 312 and the signal transmission line 313 are laid out on different surfaces of the circuit board, the impedance-adjusting conductive line 312 and the signal transmission line 313 may be electrically connected to each other through the conductive via.
Referring to fig. 4, fig. 4 is a waveform diagram of Time Domain Reflectometry (TDR) measured by a layout structure according to an embodiment of the invention. The time domain reflectometry of fig. 4 can measure the input signal as a square wave signal with 25 picoseconds. Curve 410 represents the time domain reflection curve without the addition of an impedance tuning wire; curve 420 represents the time zone reflection curve when adding an impedance tuning wire that wraps around a pad half turn; curve 430 represents the time domain reflection curve when an impedance tuning wire is added around pad 1/4 turns. Taking the specification SPC set between 70-93 ohms as an example, when the transmission impedance varies, according to the curve 410, the transmission impedance can be reduced to 58 ohms at the lowest and far below the specification SPC without adding the impedance adjusting wire; according to the curve 420, under the condition of adding a half-turn impedance adjusting lead, the transmission impedance can be changed to 75 ohms and meet the requirements of specification SPC; according to the curve 430, with the addition of 1/4 turns of the impedance adjusting wire, the transmission impedance can be varied to 70 ohms and still meet the requirements of the specification SPC.
Referring to fig. 5, fig. 5 is a schematic diagram of a circuit board structure according to an embodiment of the invention. Circuit board structure 500 includes circuit boards 510 and 520. The circuit board 510 may carry integrated circuits IC1, IC2 thereon. The integrated circuits IC1, IC2 may be disposed on any surface of the circuit board 510 without fixed limitations. The circuit board 510 has a layout structure 511 thereon. The layout structure 511 is connected to the IC2 and is used for transmitting and receiving signals with the IC 2. The layout structure 511 can be constructed as in the embodiments of fig. 1 to 3, and is not repeated herein.
Layout structure 511 has a pad 5111, and pad 5111 can be electrically connected to conductive VIA. The circuit boards 510 and 520 may be electrically connected to each other through the conductive VIAs VIA.
In addition, the circuit board 520 in this embodiment may or may not carry an integrated circuit thereon. The designer can set the design according to the requirement without any special limitation.
Referring to fig. 6, fig. 6 is a schematic diagram illustrating a transmission structure of a high speed transmission interface according to an embodiment of the invention. In fig. 6, the pad 611, the conductive via 621 and the pad 631 form a first conductive line structure for transmitting a first signal, and the pad 612, the conductive via 622 and the pad 632 form a second conductive line structure for transmitting a second signal, wherein the first signal and the second signal are differential signals. The pads 611 and 612 can be disposed on the same first circuit board, and the pads 621 and 622 can be disposed on the same second circuit board, wherein the first circuit board is different from the second circuit board.
In the present embodiment, taking the first conductive line structure as an example, the first conductive line structure has a self-inductance L11, and has a mutual inductance L12 generated between the first conductive line structure and the second conductive line structure. The first conductive line structure has a self-capacitance C11 and a mutual capacitance C22 generated between the first conductive line structure and the second conductive line structure.
By providing an impedance adjusting wire at least partially surrounding the bond pad, the self-inductance L11 may be increased in embodiments of the present invention. In addition, mutual inductance L12 and mutual capacitance C12 can be reduced and reduce the electric and magnetic fields that the signal cross between transmission lines. Embodiments of the present invention compensate for the large circuit (e.g., self-capacitance C11) created by the stacked multi-layer circuit board structure by creating an inductive path through the impedance-adjusting wire that at least partially surrounds the bond pad. In this embodiment, the impedance difference Zdiff between the first wire structure and the second wire structure can be expressed as follows:
Figure BDA0002978956650000061
in summary, the circuit board layout structure provided by the present invention arranges the impedance adjusting wires between the bonding pads and the signal transmission lines. The impedance adjusting wires are arranged along the periphery of the welding pad and are partially distributed in a mode of surrounding the welding pad, so that the reflection phenomenon possibly generated in the signal transmission process can be reduced, and the quality of signal transmission is effectively improved.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (11)

1. A circuit board layout structure, comprising:
at least one signal transmission line arranged on the first circuit board;
at least one welding pad arranged on the first circuit board; and
at least one impedance adjusting wire, which is arranged on the first circuit board and electrically connected between the at least one signal transmission line and the at least one welding pad, is arranged along the periphery of the at least one welding pad and at least partially surrounds the at least one welding pad.
2. The circuit board layout structure of claim 1, wherein the at least one impedance adjusting wire and the at least one pad are disposed on the same surface of the first circuit board or disposed on different surfaces of the first circuit board, respectively.
3. The circuit board layout structure of claim 2, wherein the at least one impedance-adjusting wire is disposed adjacent to the at least one pad when the at least one impedance-adjusting wire and the at least one pad are disposed on the same surface of the first circuit board.
4. The circuit board layout structure of claim 2, wherein the at least one impedance adjusting wire is disposed according to a profile of the at least one pad when the at least one impedance adjusting wire and the at least one pad are disposed on different surfaces of the first circuit board.
5. The circuit board layout structure of claim 1, wherein the impedance provided by the at least one impedance-adjusting wire is greater than the impedance provided by the at least one pad.
6. The circuit board layout structure of claim 1, wherein the at least one impedance adjusting wire surrounds 1/4, 1/2, 3/4 or all of the periphery of the at least one pad.
7. The circuit board layout structure of claim 1, wherein the at least one pad is electrically connected to the second circuit board through a connection structure.
8. A circuit board structure, comprising:
a first circuit board having:
at least one signal transmission line arranged on the first circuit board;
at least one welding pad arranged on the first circuit board; and
at least one impedance adjusting wire, disposed on the first circuit board and electrically connected between the at least one signal transmission line and the at least one pad, the at least one impedance adjusting wire being disposed along a periphery of the at least one pad and at least partially surrounding the at least one pad; and
a second circuit board electrically connected to the second circuit board through at least one connection structure.
9. The circuit board structure of claim 8, wherein the at least one impedance-tuning wire and the at least one solder pad are disposed on the same surface of the first circuit board or are disposed on different surfaces of the first circuit board, respectively.
10. The circuit board structure according to claim 9, wherein the at least one impedance adjusting wire is disposed according to a profile of the at least one pad when the at least one impedance adjusting wire and the at least one pad are disposed on different surfaces of the first circuit board.
11. The circuit board structure of claim 8, wherein the impedance provided by the at least one impedance adjustment wire is greater than the impedance provided by the at least one bond pad.
CN202110282035.9A 2021-03-16 2021-03-16 Circuit board structure and layout structure thereof Pending CN115087189A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110282035.9A CN115087189A (en) 2021-03-16 2021-03-16 Circuit board structure and layout structure thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110282035.9A CN115087189A (en) 2021-03-16 2021-03-16 Circuit board structure and layout structure thereof

Publications (1)

Publication Number Publication Date
CN115087189A true CN115087189A (en) 2022-09-20

Family

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Application Number Title Priority Date Filing Date
CN202110282035.9A Pending CN115087189A (en) 2021-03-16 2021-03-16 Circuit board structure and layout structure thereof

Country Status (1)

Country Link
CN (1) CN115087189A (en)

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