JP2002009511A - Printed circuit board and its impedance adjustment method - Google Patents
Printed circuit board and its impedance adjustment methodInfo
- Publication number
- JP2002009511A JP2002009511A JP2000187957A JP2000187957A JP2002009511A JP 2002009511 A JP2002009511 A JP 2002009511A JP 2000187957 A JP2000187957 A JP 2000187957A JP 2000187957 A JP2000187957 A JP 2000187957A JP 2002009511 A JP2002009511 A JP 2002009511A
- Authority
- JP
- Japan
- Prior art keywords
- printed circuit
- circuit board
- characteristic impedance
- adjusting
- impedance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Manufacturing Of Printed Wiring (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、プリント基板特に
差動信号を有するプリント基板とそのインピーダンス調
整方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board, and more particularly to a printed circuit board having a differential signal and a method for adjusting the impedance of the printed circuit board.
【０００２】[0002]
【従来の技術】プリント基板の特性インピーダンスのバ
ラツキは反射の発生原因となり、信号伝送特性を劣化さ
せ、誤動作の要因となる。そこで製造されたプリント基
板に対してＴＤＲ（Time Domain Reflectometry）法な
どによって特性インピーダンスを測定し、所望の精度を
満足しないプリント基板を廃棄することを行ってきた。2. Description of the Related Art Variations in the characteristic impedance of a printed circuit board cause reflection, degrade signal transmission characteristics, and cause malfunctions. Therefore, the characteristic impedance of the manufactured printed circuit board is measured by a TDR (Time Domain Reflectometry) method or the like, and the printed circuit board that does not satisfy the desired accuracy has been discarded.
【０００３】プリント基板の特性インピーダンスは、層
の断面構造（パターンの幅や高さ、電圧／グランド層と
の距離）や、コア材ならびにプリプレグ材の比誘電率で
決まるが、製造バラツキによって所望のインピーダンス
精度を満足しないプリント基板がロットの単位で発生し
てしまうことがあり、このことが歩留りに大きく影響し
ている。The characteristic impedance of a printed circuit board is determined by the cross-sectional structure of the layer (width and height of the pattern, distance from the voltage / ground layer) and the relative permittivity of the core material and the prepreg material. Printed circuit boards that do not satisfy the impedance accuracy may be generated in units of lots, which greatly affects the yield.
【０００４】また、差動信号のレイアウト設計において
は、差動信号対の各伝送路長を一致させる目的から、本
来一定であるべき差動信号対の線間距離が変動した部分
ができてしまう。プリント基板の特性インピーダンスＺ
o は、Ｚo ＝（Ｌ／Ｃ）1/2で表されるが、差動信号対
の線間距離が拡大した部分においては、相互インダクタ
ンスの減少によってＬ成分が増加し、結果として特性イ
ンピーダンスが増大してしまう。Further, in the layout design of the differential signal, a part where the line distance of the differential signal pair which should be constant should be changed for the purpose of matching the lengths of the transmission lines of the differential signal pair. . Printed circuit board characteristic impedance Z
is represented by Zo = (L / C) 1/2 , but in a portion where the line distance of the differential signal pair is increased, the L component increases due to the decrease in the mutual inductance, and as a result, the characteristic impedance is increased. Will increase.
【０００５】さらに、プリント基板上に実装されたスタ
ッキングコネクタなどのコネクタの表面実装端子は金属
表面がむき出しの状態であるため、インダクタンス成分
が支配的つまり特性インピーダンスが高く、やはり反射
による信号伝送特性の劣化をもたらす要因となる。Further, since the metal surface of a surface mounting terminal of a connector such as a stacking connector mounted on a printed circuit board is exposed, the inductance component is dominant, that is, the characteristic impedance is high, and the signal transmission characteristic due to reflection is also high. It causes deterioration.
【０００６】[0006]
【発明が解決しようとする課題】以上のように、プリン
ト基板において良好な信号伝送特性を得るためには、そ
の基板の特性インピーダンスが規定精度枠内にあること
が要求される。しかしながら、差動信号対の線間距離が
線長調整などのため部分的に広がった部分やコネクタの
表面実装端子の部分では、特性インピーダンスが高くな
り、反射によって信号伝送特性が劣化するという問題が
あった。As described above, in order to obtain good signal transmission characteristics on a printed board, it is required that the characteristic impedance of the board be within a specified accuracy frame. However, there is a problem that the characteristic impedance is high in the part where the line distance of the differential signal pair is partially widened due to line length adjustment and the like and the surface mount terminal part of the connector, and the signal transmission characteristic is deteriorated by reflection. there were.
【０００７】本発明はこのような課題を解決するためな
されたもので、その目的とするところは、差動信号対の
線間距離が線長調整などのため広がった部分の特性イン
ピーダンスを容易に補正することのできるプリント基板
とそのインピーダンス調整方法を提供することにある。The present invention has been made to solve such a problem, and an object of the present invention is to easily reduce the characteristic impedance of a portion where the line distance of a differential signal pair is widened due to line length adjustment or the like. An object of the present invention is to provide a printed circuit board that can be corrected and a method of adjusting the impedance of the printed circuit board.
【０００８】また、本発明は、プリント基板の製造後に
特性インピーダンスを補正して歩留りを高めることので
きるプリント基板のインピーダンス調整方法を提供する
ことにある。Another object of the present invention is to provide a printed circuit board impedance adjusting method capable of correcting a characteristic impedance after manufacturing the printed circuit board and improving the yield.
【０００９】[0009]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明のプリント基板は、基材と、この基材の上
に形成された差動信号の伝送路と、前記差動信号の伝送
路の線長調整部分に被着された特性インピーダンス調整
用の誘電体とを有して構成されるものである。In order to achieve the above object, a printed circuit board according to the present invention comprises: a base material; a transmission line for a differential signal formed on the base material; And a dielectric for characteristic impedance adjustment attached to a line length adjustment portion of the transmission line.
【００１０】また、上記の目的を達成するために、本発
明のプリント基板のインピーダンス調整方法は、差動信
号の伝送路の線長調整部分に誘電体塗膜を形成して特性
インピーダンスの調整を行うものである。In order to achieve the above object, a method for adjusting the impedance of a printed circuit board according to the present invention is to adjust a characteristic impedance by forming a dielectric coating film on a line length adjusting portion of a differential signal transmission line. Is what you do.
【００１１】すなわち、本発明は、差動信号対の線長調
整のため線間距離を広げた部分に比誘電率が１以上の物
質を被着することによって、差動信号対の線長調整部分
の特性インピーダンスを低減して、反射による信号伝送
劣化を抑制することが可能となる。That is, the present invention provides a method for adjusting the line length of a differential signal pair by applying a substance having a relative dielectric constant of 1 or more to a portion where the line distance is widened for adjusting the line length of the differential signal pair. By reducing the characteristic impedance of the portion, it is possible to suppress signal transmission deterioration due to reflection.
【００１２】また、上記の目的を達成するために、本発
明のプリント基板のインピーダンス調整方法は、プリン
ト基板の表面に、シルク印刷によってラベルの形成と同
時に特性インピーダンス調整用の誘電体塗膜の形成を行
うものである。According to another aspect of the present invention, there is provided a method of adjusting the impedance of a printed circuit board, comprising forming a label on a surface of the printed circuit board by silk printing and simultaneously forming a dielectric coating for adjusting characteristic impedance. Is what you do.
【００１３】このようにラベル形成と特性インピーダン
ス調整用の塗膜形成を一つのシルク印刷工程で同時に行
うことによって、特性インピーダンス調整用の塗膜形成
の追加による製造コストの増加を防止することが可能に
なる。As described above, by simultaneously forming the label and the coating film for adjusting the characteristic impedance in one silk printing process, it is possible to prevent an increase in the production cost due to the addition of the coating film for adjusting the characteristic impedance. become.
【００１４】[0014]
【発明の実施の形態】以下、図面を参照して本発明の実
施形態を説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１５】図１は、本実施形態のプリント基板におけ
る信号伝送路の部分の構成を示す図である。同図におい
て、１はコア材、２は電圧／グランドプレーン、３はレ
ジスト膜などの絶縁層、４は信号ライン、５はたとえば
シルク印刷などにより絶縁層３の表面に被着した誘電体
からなる塗膜である。誘電体５は比誘電率１以上の物質
であれば何でもよいが、生産性を考慮して、ここではプ
リント基板へのラベル形成に用いられるシルク印刷を使
用している。FIG. 1 is a diagram showing a configuration of a signal transmission path portion of a printed circuit board according to the present embodiment. In the figure, 1 is a core material, 2 is a voltage / ground plane, 3 is an insulating layer such as a resist film, 4 is a signal line, and 5 is a dielectric material adhered to the surface of the insulating layer 3 by, for example, silk printing. It is a coating film. The dielectric 5 may be any substance as long as it has a relative dielectric constant of 1 or more. In view of productivity, silk printing used for forming a label on a printed circuit board is used here.
【００１６】この誘電体５による塗膜は、プリント基板
の断面構造においてＣ成分を増大させる。プリント基板
の特性インピーダンスＺo はＺo ＝（Ｌ／Ｃ）1/2 で表
されるので、誘電体５をプリント基板に被着することに
よってＣ成分が増加し、もって特性インピーダンスＺo
が低下する。The coating of the dielectric 5 increases the C component in the sectional structure of the printed circuit board. Since the characteristic impedance Zo of the printed circuit board is expressed by Zo = (L / C) 1/2 , the C component is increased by attaching the dielectric 5 to the printed circuit board, and the characteristic impedance Zo is thereby increased.
Decrease.
【００１７】そこで、製造されたプリント基板の特性イ
ンピーダンスをＴＤＲ法などによって測定し、測定値が
規定精度枠の上限を越えたプリント基板を対象に、本発
明の方法により特性インピーダンスの調整を行うことに
よって、プリント基板の廃棄数を減じて歩留りを向上さ
せることが可能である。Therefore, the characteristic impedance of the manufactured printed circuit board is measured by the TDR method or the like, and the characteristic impedance is adjusted by the method of the present invention for the printed circuit board whose measured value exceeds the upper limit of the specified accuracy frame. Accordingly, it is possible to reduce the number of discarded printed circuit boards and improve the yield.
【００１８】図２に、本実施形態のインピーダンス調整
方法の流れを示す。この例では、あらかじめ、インピー
ダンスの低減効果の異なるいくつかの誘電体パターンを
作成しておき、ステップ２１のＴＤＲ検査を通してＮＧ
と判定されたプリント基板の特性インピーダンスの測定
値に対して最適な誘電体パターンを選択し（ステップ２
３）、選択した誘電体パターンを当該プリント基板に印
刷する（ステップ２４）。ここで、プリント基板への誘
電体パターンの印刷は、シルク印刷によって、当該プリ
ント基板へのラベルの形成と同時に同材料を使って行う
ことが好適である。このようにすることで、ラインの工
数や使用材料を増やすことなくプリント基板のインピー
ダンス調整を行うことができ、歩留りの向上と相俟って
大幅なコスト減が実現される。FIG. 2 shows a flow of the impedance adjusting method according to the present embodiment. In this example, several dielectric patterns having different impedance reduction effects are created in advance, and NG
The most suitable dielectric pattern is selected for the measured value of the characteristic impedance of the printed circuit board determined to be (Step 2).
3) Print the selected dielectric pattern on the printed circuit board (step 24). Here, the printing of the dielectric pattern on the printed circuit board is preferably performed by silk printing using the same material at the same time as the formation of the label on the printed circuit board. By doing so, the impedance of the printed circuit board can be adjusted without increasing the number of man-hours and materials used in the line, and a significant cost reduction is realized together with an improvement in the yield.
【００１９】また、差動信号の配線設計においては、差
動信号対の各伝送路長を一致させるために、たとえば図
３に示すように、本来一定であるべき差動信号対３１，
３２の線間距離が広がった部分（線長調整部分）３３が
できる。プリント基板の特性インピーダンスＺo は、Ｚ
o ＝（Ｌ／Ｃ）1/2 で表すことができるが、上記のよう
な差動信号対３１，３２の線長調整部分３３においては
相互インダクタンスの減少によってＬ成分が増加し、結
果として特性インピーダンスが増大することになる。そ
こで、このような差動信号対３１，３２の線長調整部分
３３に誘電体５を被着することによって、その部分の特
性インピーダンスが低減し、特性インピーダンスの不連
続を緩和させることができる。この場合も、プリント基
板に被着させる誘電体５のパターンやその厚み、材料な
どを最適に選択することによって特性インピーダンスを
さらに微細に調整することが可能であり、高周波帯域で
の反射による信号伝送劣化を最小限にできる。In the wiring design of the differential signal, in order to make the lengths of the transmission lines of the differential signal pair coincide with each other, for example, as shown in FIG.
A portion (line length adjustment portion) 33 in which the distance between the lines 32 is widened is formed. The characteristic impedance Zo of the printed circuit board is Z
o = (L / C) 1/2 , but in the line length adjusting portion 33 of the differential signal pair 31, 32 as described above, the L component increases due to the decrease in the mutual inductance, and as a result, the characteristic The impedance will increase. Thus, by applying the dielectric 5 to the line length adjusting portion 33 of the differential signal pair 31, 32, the characteristic impedance of that portion is reduced, and the discontinuity of the characteristic impedance can be reduced. Also in this case, the characteristic impedance can be further finely adjusted by optimally selecting the pattern of the dielectric 5 to be adhered to the printed circuit board, its thickness, material, and the like, and signal transmission by reflection in a high-frequency band. Deterioration can be minimized.
【００２０】たとえば、図４に示すように、差動信号対
３１，３２の線間距離が最大に広がった部分で誘電体５
によるＣ成分増加効果も最大となるように、たとえば両
端部に切り欠き３４を設けることによって、線間距離が
徐々に広がった部分から最大に広がった部分まで特性イ
ンピーダンスＺoが同じになるようなパターンを用いる
ことが効果的な手段として挙げられる。For example, as shown in FIG. 4, the portion of the dielectric 5 where the line distance between the differential signal pairs 31 and 32 is maximized is
For example, by providing notches 34 at both ends, the characteristic impedance Zo is the same from the portion where the line distance gradually increases to the portion where the line distance increases to maximize the effect of increasing the C component due to Is an effective means.
【００２１】さらに、図５に示すように、プリント基板
上に実装されたスタッキングコネクタなどのコネクタ５
１の表面実装端子５２は金属表面がむき出しの状態であ
るため、インダクタンス成分が支配的つまり特性インピ
ーダンスが高く、やはり反射による信号品質の低下をも
たらす要因となる。このような表面実装端子５２にも誘
電体５を被着して特性インピーダンスを減じることによ
って、反射による信号劣化を有効に低減することができ
る。Further, as shown in FIG. 5, a connector 5 such as a stacking connector mounted on a printed circuit board is provided.
Since the metal surface of the first surface mount terminal 52 is exposed, the inductance component is dominant, that is, the characteristic impedance is high, and this also causes a deterioration in signal quality due to reflection. By reducing the characteristic impedance by attaching the dielectric 5 also to such a surface mount terminal 52, signal deterioration due to reflection can be effectively reduced.
【００２２】以上説明したように、本実施形態の特性イ
ンピーダンス調整方法によれば、製造後にプリント基板
の特性インピーダンスを微調整して所望の値に近づける
ことができ、特性インピーダンスのバラツキによる信号
伝送劣化を最小限にできる。特に、差動信号対の各伝送
路長を一致させるために差動信号対の線間距離が広がっ
た部分の特性インピーダンスを微細に調整することがで
きるので、特性インピーダンスの不連続を緩和すること
ができ、信号伝送特性の優れたプリント基板を高い歩留
りで得ることができる。As described above, according to the characteristic impedance adjusting method of this embodiment, the characteristic impedance of the printed circuit board can be finely adjusted to a desired value after manufacturing, and the signal transmission deterioration due to the characteristic impedance variation can be achieved. Can be minimized. In particular, it is possible to finely adjust the characteristic impedance of the portion where the line distance of the differential signal pair is widened in order to match the transmission path lengths of the differential signal pair, so that the discontinuity of the characteristic impedance can be reduced. Thus, a printed circuit board having excellent signal transmission characteristics can be obtained with a high yield.
【００２３】[0023]
【発明の効果】以上説明したように、本発明によれば、
差動信号対の線長調整部分に誘電体を被着することによ
って、その差動信号対の線長調整部分の特性インピーダ
ンスを低減して反射による信号伝送劣化を抑制すること
ができる。また、ラベル形成と特性インピーダンス調整
用の誘電体塗膜形成を一つのシルク印刷工程で行うこと
によって、特性インピーダンス調整用の塗膜形成の追加
による製造コストの増加を防止することが可能になる。As described above, according to the present invention,
By applying a dielectric to the line length adjustment portion of the differential signal pair, the characteristic impedance of the line length adjustment portion of the differential signal pair can be reduced, and signal transmission deterioration due to reflection can be suppressed. In addition, by forming the label and forming the dielectric coating for adjusting the characteristic impedance in one silk printing process, it is possible to prevent an increase in manufacturing cost due to the addition of the coating for adjusting the characteristic impedance.
【図１】本発明の実施形態であるプリント基板の伝送路
部の構成を示す図。FIG. 1 is a diagram showing a configuration of a transmission path section of a printed circuit board according to an embodiment of the present invention.
【図２】本実施形態のインピーダンス調整方法の流れを
示すフローチャート。FIG. 2 is a flowchart showing the flow of the impedance adjustment method according to the embodiment;
【図３】本発明の差動信号対の線長調整部分へのインピ
ーダンス調整方法を示す図。FIG. 3 is a diagram showing a method of adjusting the impedance of a differential signal pair to a line length adjusting portion according to the present invention.
【図４】図３の差動信号対の線長調整部分へのインピー
ダンス調整方法による誘電体のパターン例を示す図。FIG. 4 is a view showing an example of a dielectric pattern by an impedance adjustment method for a line length adjustment portion of the differential signal pair of FIG. 3;
【図５】コネクタの表面実装端子へのインピーダンス調
整方法を示す図。FIG. 5 is a diagram showing a method of adjusting the impedance of the connector to the surface-mounted terminals.
１ コア材 ２ 電圧／グランドプレーン ３ 絶縁層 ４ 信号ライン ５ 誘電体 ３１，３２ 差動信号対 ３３ 線長調整部分 ３４ 切り欠き ５１ コネクタ ５２ 表面実装端子 DESCRIPTION OF SYMBOLS 1 Core material 2 Voltage / ground plane 3 Insulating layer 4 Signal line 5 Dielectric 31, 32 Differential signal pair 33 Line length adjustment part 34 Notch 51 Connector 52 Surface mount terminal
Claims (4)
信号の伝送路と、 前記差動信号の伝送路の線長調整部分に被着された特性
インピーダンス調整用の誘電体とを有することを特徴と
するプリント基板。1. A base material, a transmission path for a differential signal formed on the base material, and a dielectric for adjusting a characteristic impedance attached to a line length adjustment portion of the transmission path for the differential signal And a printed circuit board comprising:
のインピーダンス調整方法において、 前記差動信号の伝送路の線長調整部分に誘電体塗膜を形
成して特性インピーダンスの調整を行うことを特徴とす
るプリント基板のインピーダンス調整方法。2. A method of adjusting the impedance of a printed circuit board having a differential signal transmission path, comprising: adjusting a characteristic impedance by forming a dielectric coating on a line length adjustment portion of the differential signal transmission path. Characteristic impedance adjustment method for printed circuit boards.
ってラベルの形成と同時に特性インピーダンス調整用の
誘電体塗膜の形成を行うことを特徴とするプリント基板
のインピーダンス調整方法。3. A method for adjusting the impedance of a printed circuit board, the method comprising: forming a label on the surface of the printed circuit board by silk printing and simultaneously forming a dielectric coating for adjusting characteristic impedance.
ってラベルの形成と同時に差動信号の伝送路の線長調整
部分の特性インピーダンスを調整する誘電体塗膜の形成
を行うことを特徴とするプリント基板のインピーダンス
調整方法。4. A printing method comprising: forming a label on a surface of a printed circuit board by silk-screen printing and simultaneously forming a dielectric coating film for adjusting a characteristic impedance of a line length adjusting portion of a differential signal transmission path. How to adjust the impedance of the board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000187957A JP2002009511A (en) | 2000-06-22 | 2000-06-22 | Printed circuit board and its impedance adjustment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000187957A JP2002009511A (en) | 2000-06-22 | 2000-06-22 | Printed circuit board and its impedance adjustment method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002009511A true JP2002009511A (en) | 2002-01-11 |
Family
ID=18687833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000187957A Withdrawn JP2002009511A (en) | 2000-06-22 | 2000-06-22 | Printed circuit board and its impedance adjustment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002009511A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7338290B2 (en) | 2005-10-25 | 2008-03-04 | Ricoh Company, Ltd. | Printed wiring board with a plurality of pads and a plurality of conductive layers offset from the pads |
| JP2014106699A (en) * | 2012-11-27 | 2014-06-09 | Mitsubishi Electric Corp | Bus system |
| CN113252985A (en) * | 2021-07-16 | 2021-08-13 | 深圳市迅特通信技术股份有限公司 | Measuring device and measuring method for measuring impedance of high-speed signal line in optical module |
-
2000
- 2000-06-22 JP JP2000187957A patent/JP2002009511A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7338290B2 (en) | 2005-10-25 | 2008-03-04 | Ricoh Company, Ltd. | Printed wiring board with a plurality of pads and a plurality of conductive layers offset from the pads |
| JP2014106699A (en) * | 2012-11-27 | 2014-06-09 | Mitsubishi Electric Corp | Bus system |
| CN113252985A (en) * | 2021-07-16 | 2021-08-13 | 深圳市迅特通信技术股份有限公司 | Measuring device and measuring method for measuring impedance of high-speed signal line in optical module |
| CN113252985B (en) * | 2021-07-16 | 2021-10-01 | 深圳市迅特通信技术股份有限公司 | Measuring device and measuring method for measuring impedance of high-speed signal line in optical module |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20070904 |