1、 IEC TR 63017 Edition 1.0 2015-12 TECHNICAL REPORT Flexible printed circuit boards (FPCBs) Method of compensation of impedance variations IEC TR 63017:2015-12(en) colour inside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2015 IEC, Geneva, Switzerland All rights reserved. Unless otherwise speci
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10、 wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csciec.ch. IEC TR 63017 Edition 1.0 2015-12 TECHNICAL REPORT Flexible printed circuit boards (FPCBs) Method of compensation of impedance variations INTERNATIONAL ELECTROTECHNICA
11、L COMMISSION ICS 31.180 ISBN 978-2-8322-3083-1 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. colour inside 2 IEC TR 63017:2015 IEC 2015 CONTENTS FOREWORD . 3 1 Scope 5 2 Normative references
12、 5 3 Apparatus 5 3.1 Time domain reflectometry 5 3.2 Block diagram for impedance measuring . 5 4 Test specimen . 6 4.1 General . 6 4.2 Structure . 6 4.3 Test method 7 4.4 Calculation 8 5 Report . 9 Annex A (normative) Block diagram for impedance measuring with TDR . 10 Annex B (informative) Theoreti
13、cal background 11 Annex C (informative) Example of an impedance measurement with TDR . 12 Annex D (informative) Hand contact effect 13 Annex E (informative) Test result 14 E.1 Shield 1 FPCB 14 E.2 Shield 2 FPCB 15 Bibliography 16 Figure 1 TDR test system. 5 Figure 2 Two types of impedance structure
14、of FPCB 6 Figure 3 Schematic diagram of a test specimen . 7 Figure 4 Impedance value of two type FPCB (bare and shield) 8 Figure 5 Compensation value (L) of the Cu line width for the shield FPCB . 9 Figure A.1 TDR test system according to IPC 2141a-9-1 10 Figure A.2 TDR test system according to Agil
15、ent TDR 54754A . 10 Figure B.1 Two types of impedance structure of FPCBs . 11 Figure B.2 Comparison of the impedance value of a bare FPCB versus a shield FPCB 11 Figure C.1 Photographic view of the impedance measurement with TDR . 12 Figure D.1 Effect of impedance variation by hand contact for bare
16、FPCB . 13 Figure E.1 Measurement result of the test specimen for shield 1 FPCB 14 Figure E.2 Measurement result of the test specimen for shield 2 FPCB 15 Table E.1 Cross-section of test specimen with using shield 1 FPCB . 14 Table E.2 Cross-section of test specimen with using shield 2 FPCB . 15 IEC
17、TR 63017:2015 IEC 2015 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FLEXIBLE PRINTED CIRCUIT BOARDS (FPCBs) METHOD OF COMPENSATION OF IMPEDANCE VARIATIONS FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrot
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29、dard, for example “state of the art“. IEC TR 63017, which is a technical report, has been prepared by IEC technical committee 91: Electronics assembly technology. The text of this technical report is based on the following documents: Enquiry draft Report on voting 91/1283/DTR 91/1308/RVC Full inform
30、ation on the voting for the approval of this technical report can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. 4 IEC TR 63017:2015 IEC 2015 The committee has decided that the contents of this publi
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32、cation may be issued at a later date. IMPORTANT The colour inside logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer. IEC TR 6
33、3017:2015 IEC 2015 5 FLEXIBLE PRINTED CIRCUIT BOARDS (FPCBs) METHOD OF COMPENSATION OF IMPEDANCE VARIATIONS 1 Scope This Technical Report specifies a compensation method of Cu linewidth according to impeadance reduction by using noise suppression materials (hereafter referred to as NSMs) for FPCBs.
34、This Technical Report presents an optimum result for maintaining a designated performance of FPCBs by using NSMs. It also indicates a measuring method for an impedance variation of FPCBs using NSMs with the prevailing TDR (time domain reflectometry) method. This method is resticted to measuring only
35、 the variation of an impedance value in accordance with the variation of the Cu linewidth by using NSMs for FPCBs. This report, however, neither determines nor indicates the structure or material of FPCBs. 2 Normative references The following documents, in whole or in part, are normatively reference
36、d in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IPC 2141A Design Guide for High-Speed Controlled Impedance Circuits Boards htt
37、p:/www.ipc.org/ 3 Apparatus 3.1 Time domain reflectometry Time domain reflectometry (hereafter referred to as TDR) is utilized to identify the impedance data at the specific frequency range of FPCBs. 3.2 Block diagram for impedance measuring Figure 1 gives one example of a TDR setup. Figure 1 TDR te
38、st system IEC 6 IEC TR 63017:2015 IEC 2015 NOTE A guideline for TDR is provided in Annex A. 4 Test specimen 4.1 General FPCBs using NSMs should reduce the effect of electro-magnetic interference. However, without appropriate application of NSMs, it may cause poor signal quality on the FPCB due to th
39、e impedance variation of Cu circuit lines. A major factor of impedance variation using NSMs is due to the structure variation of FPCBs, as shown in Figure 2. Figure 2a Figure 2b NOTE A guideline for the theoretical background of impedance variation is provided in Annex B. Figure 2 Two types of imped
40、ance structure of FPCB 4.2 Structure Test specimens shall be designed by two structures, i.e. with and without using NSMs in one FPCB board. Test specimens shall be divided into two halves with one board (consisting of the two parts of one bare FPCB and one shield FPCB) for equitable estimation. Thi
41、s structure has the merit of uniformly measuring at once a bare and a shield FPCB under the same condition. One FPCB without using NSMs has a structure of a micro-strip line. This type is called bare FPCB. Another FPCB using NSMs has a structure of a strip line. This type is called shield FPCB (see
42、Figure 3). A Cu line is formed with a linear distance direction, because the variation of the shield effect is very weak for a curved line. Generally, the number of Cu patterns of the test specimen can be over the 5 (for example LW1 LW5) for verification of the characteristic impedance (Z 0 ). But t
43、he number and width of the Cu line shall vary in accordance with the suppliers activity. IEC Bare FPCB Cover layer PI PI Adhesive S(Cu) GND (Cu) G(Cu) G(Cu) Via hole IEC Shield FPCB Cover layer PI PI Adhesive S(Cu) GND (Cu) G(Cu) G(Cu) NSMs IEC TR 63017:2015 IEC 2015 7 Figure 3 Schematic diagram of
44、a test specimen Size, spacing and number of via holes for test specimens shall not be limited, but sufficiently represented. Especially, via holes offer an important role to contact the NSMs with the ground plan of shield FPCB. The number of via holes shall be as agreed between user and supplier (he
45、reafter referred to as AABUS). The length of the test specimen shall be over 5 cm in order to obtain stable values from the measuring equipment. Each end of the test specimen should consist of SMA (subminiature A) connectors. For discernment of a Cu line-width, write each number to the bare end of t
46、he test specimen near the SMA connector. The decision of width and thickness of a test specimen shall depend on to the pitch or the number of the Cu line or according to the requirements of the user. However, generally the structure of the test coupon shall be AABUS. An impedance value for FPCBs sha
47、ll be changed with respect to the Cu pattern width, layer structure, thickness and materials. The structure and materials of the test specimens is required depending on the users sample specifications. But the variation of these test specimens is not important, because the user of FPCBs shall check
48、only the impedance variation effect by using NSMs for the users sample specification. 4.3 Test method In order to measure the proper impedance value for the test specimen, the following procedures shall be empoyed. IEC Bare FPCB LW1 LW2 LW3 LWn LW1 LW2 LW3 LWn Shield FPCB 5 Via hole 8 IEC TR 63017:2
49、015 IEC 2015 a) Impedance values of the test specimen shall be measured by employing TDR, test specimen and coaxial cable according to IPC 2141A. b) Measurement conditions shall be set by means of the TDR, such as dielectric constant, measurement point, rising time, pulse width, etc. c) The impedance value of the test specimen shall be measured according to the Cu line width for bare FPCB. d) The measurement
