1、BRITISH STANDARD BS EN 60512-25-5: 2004 Connectors for electronic equipment Tests and measurements Part 25-5: Test 25e Return loss The European Standard EN 60512-25-5:2004 has the status of a British Standard ICS 31.220.10 BS EN 60512-25-5:2004 This British Standard was published under the authority
2、 of the Standards Policy and Strategy Committee on 30 September 2004 BSI 30 September 2004 ISBN 0 580 44531 3 National foreword This British Standard is the official English language version of EN 60512-25-5:2004. It is identical with IEC 60512-25-5:2004. The UK participation in its preparation was
3、entrusted by Technical Committee EPL/48, Electromechanical components and mechanical components, to Subcommittee EPL/48/2, Connectors for electronic equipment, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross
4、-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of B
5、ritish Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; pre
6、sent to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an
7、 inside front cover, the EN title page, pages 2 to 12, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60512-25-5 NORME EUROPENNE EUR
8、OPISCHE NORM September 2004 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2004 CENELEC - All rights of exploitation in any for
9、m and by any means reserved worldwide for CENELEC members. Ref. No. EN 60512-25-5:2004 E ICS 31.220.10 English version Connectors for electronic equipment Tests and measurements Part 25-5: Test 25e Return loss (IEC 60512-25-5:2004) Connecteurs pour quipements lectroniques Essais et mesures Partie 25
10、-5: Essai 25e Affaiblissement de rflexion (CEI 60512-25-5:2004) Steckverbinder fr elektronische Einrichtungen Mess- und Prfverfahren Teil 25-5: Prfung 25e Rckflussdmpfung (IEC 60512-25-5:2004) This European Standard was approved by CENELEC on 2004-09-01. CENELEC members are bound to comply with the
11、CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or
12、to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the officia
13、l versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia,
14、 Spain, Sweden, Switzerland and United Kingdom. EN 61502-52-52:400 - - 2 Foreword The text of document 48B/1447/FDIS, future edition 1 of IEC 60512-25-5, prepared by SC 48B, Connectors, of IEC TC 48, Electromechanical components and mechanical structures for electronic equipment, was submitted to th
15、e IEC-CENELEC parallel vote and was approved by CENELEC as EN 60512-25-5 on 2004-09-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2005-06-01 latest date by which the nat
16、ional standards conflicting with the EN have to be withdrawn (dow) 2007-09-01 _ Endorsement notice The text of the International Standard IEC 60512-25-5:2004 was approved by CENELEC as a European Standard without any modification. _ Page2 EN60512255:2004-21506-525 4002:CEI 9 CONNECTORS FOR ELECTRONI
17、C EQUIPMENT TESTS AND MEASUREMENTS Part 25-5: Test 25e Return loss 1 Scope This part of IEC 60512 is applicable to electrical connectors, sockets, cable assemblies or interconnection systems. This part of IEC 60512 describes a frequency and a time domain method to measure return loss as a function o
18、f frequency. 2 Terms and definitions For the purposes of this part of IEC 60512, the following terms and definitions apply. 2.1 return loss measure for a signal reflected by the specimen in ratio with the incident signal NOTE It can be expressed in decibels (dB). 2.2 specimen environment impedance i
19、mpedance presented to the signal conductors by the fixture. This impedance is a result of transmission lines, termination resistors, attached receivers or signal sources and fixture parasitics 3 Test resources 3.1 Equipment 3.1.1 Frequency domain A network analyzer with acceptable dynamic range for
20、the DUT (Device Under Test) is to be used. For differential measurements, a network analyzer with a multiport test set or baluns may be used. 3.1.2 Time domain A Time Domain Reflectometer (TDR), triggered impulse generator and appropiate Fast Fourier Transform (FFT) software are preferred. 3.2 Fixtu
21、re 3.2.1 General The specimen environment impedance shall match the impedance of the test equipment. Unless otherwise specified in the detail specification, typically this will be 50 for single ended measurements and 100 for differential. Page3 EN60512255:2004-21506-525 4002:CEI 11 3.2.2 Specimen co
22、nductor assignments For each measurement, the driven line shall be fixtured as indicated in the detail specification. The far end (destination) and the near end (driven) of the line shall be terminated in the specimen environment impedance specified using one of the methods in Figures A.2 or A.3. In
23、 the special case where a drive signal is differential and not balanced, the common mode energy shall be terminated. Adjacent signal lines to these should likewise be terminated if possible. NOTE Electrically long adjacent signal lines may resonate adding error to the results. Unless otherwise speci
24、fied, a 1:1 signal to ground ratio (2:1 if differential measurements are perfomed) shall be used with each end having all grounds commoned. (For an example, see Figure A.4.) 3.2.3 Specimen fixture and signal line terminations for specimen environment impedance The pair under test shall be terminated
25、 with its nominal impedance. The matched load that terminates the pair should be a pure resistive load int the frequency range of interest. NOTE The fixture geometry and materials may impact the measurements due to the fixture parasitics. Usually, the products intended use dictates the most meaningf
26、ul way to fixture it. 3.2.4 Insertion technique The fixture shall be designed to allow measurement of return loss with and without the specimen, see Figure A.1a). If baluns are used for a measurement, or minimum loss pads used for impedance matching, these are included in the fixture. Figures A.2 an
27、d A.3. show typical configurations with minimum loss pads. 3.2.5 Reference fixture technique In this technique, a separate fixture that combines both near end and far end is used for the fixture return loss measurement; see Figure A.1b). This fixture shall be a duplicate of the specimen fixture, onl
28、y without the specimen. Traces, if used, shall include fixture connectors, vias, bends and corners. If baluns are used for a differential measurement, or minimum loss pads used for impedance matching, these are included in the fixturing. Figures A.2 and A.3 show typical configurations with minimum l
29、oss pads. 4 Test specimen 4.1 Description For this test procedure, the test specimen shall be as follows: 4.1.1 Separable connectors A mated connector pair. 4.1.2 Cable assembly Assembled connectors and cables, and mating connectors. Page4 EN60512255:2004-21506-525 4002:CEI 31 4.1.3 Sockets A socket
30、 and test device. 5 Test procedure 5.1 General Unless otherwise specified, all measurement results shall contain a mimimum of 200 frequency points. Each fixture measurement and its associated specimen return loss measurement shall be taken at the same frequencies. Generate a magnitude versus frequen
31、cy plot: 10 dB per division vertical scale and log frequency sweep are recommended. When applicable, single frequency results shall be tabulated, as specified in the referencing document. NOTE The test professional should be aware of limitations of any math operation(s) performed by an instrument, (
32、e.g. normalization or software filtering). 5.2 Fixture return loss 5.2.1 General Fixture return loss shall be measured separately so that it can be removed from and compared to the specimen measurement. If the referencing document precisely specifies the fixture so that its return loss contribution
33、is known, then the fixture return loss measurement is optional. 5.2.2 Calibration When using a network analyzer, as a minimum, 1 port calibration at the reference plane (include analyzer cables but not specimen fixture) shall be performed. Where possible a full 2 port calibration is recommended. NOT
34、E 1 Results may be inaccurate when the return loss is not greater than 15 dB as the specimen return loss. NOTE 2 For the best accuracy, the calibration of the test fixture shall be performed at the test ports. That means that the adaptors shall be included in the measurement. 5.2.3 Insertion techniq
35、ue 5.2.3.1 Assemble the fixture so that the near end is connected to the far end without the specimen in between; see Figure A.1a). Connect the network analyzer ports to the appropriate locations of the driven line fixture. 5.2.3.2 Measure the fixture return loss S 11and/or S 22 . 5.2.4 Reference fi
36、xture technique 5.2.4.1 Construct a reference fixture that dublicates the specimen fixture but without the specimen. Include both near and far ends; see Figure A.1b). Connect the network analyzer ports to the appropriate locations of the driven line fixture. 5.2.4.2 Measure the fixture return loss S
37、 11and/or S 22 . Page5 EN60512255:2004-21506-525 4002:CEI 51 5.3 Specimen return loss measurement Add specimen to fixture. Connect the analyzer drive port to the near end of the fixture and the load to the far end of the fixture. Measure the specimen-with-fixture return loss in dB. 5.4 Time domain m
38、ethod This method requires that the network analyzer procedure be followed, but with the following changes. A TDR in time domain transmission (TDT) mode with a triggered short impulse generator to measure the response of the specimen to an impulse stimulus shall be used. Fast fourier transform (FFT)
39、, software is used to compute the return loss of the frequency domain. Connect the TDR output to the input of an impulse generator. Connect the output of the impulse generator to the near end of the test fixture and connect the far end of the test fixture to the load. For each measurement, measure t
40、he TDT response to the impulse stimulus. Compute the FFT of the time domain response, the result being the return loss in the frequency domain. From these data, the complex propagation constants alpha (attenuation versus frequency) and beta (phase versus frequency) may be calculated over a very wide
41、 frequency range. If combined with low frequency capacitance measurements, the specimen may be completely characterized, including return loss as well as complex impedance as functions of frequency. 6 Details to be specified The following details shall be specified in the referencing document: a) Sp
42、ecimen signal and ground assignments for each measurement. As a minimum, the driven conductor or conductor pair, the nearest signal conductors in each direction, and the associated (adjacent) grounds of all these, shall be identified. NOTE A sufficient number of lines to be measured based on a consi
43、deration of geometry, should be specified so that the best and worst case performance will be determined. lt is recommended that the following be considered: conductor spacing, conductor orientation, conductor length, etc. b) The type of drive signal, single ended or differential. Refer to 3.2.2 for
44、 the special case of differential and unbalanced signals. c) Specimen environment impedance if other than 50 for single ended or 100 for differential. d) Number of measurement points. e) Measurement frequency range. f) Tabulated single frequency results, if desired. g) Plot magnitude format, if othe
45、r than dB and log frequency. h) Any special requirements with respect to fixture and termination construction and electrical properties. i) Any special calibration technique. Page6 EN60512255:2004-21506-525 4002:CEI 71 7 Test documentation Documentation shall contain the details specified in Clause
46、6, with any exceptions, and the following: a) title of test; b) test equipment, and date of last and next calibration; c) measured fixture, measured specimen-with-fixture, and calculated specimen return loss plots and tabulated single frequency results; d) balun specifications, if used; e) observati
47、ons; f) name of operator and date of test. Page7 EN60512255:2004-21506-525 4002:CEI 91 Annex A (normative) Diagrams and schematics of fixtures and equipment Source Specimen fixture A Specimen Specimen fixture B Receiver or load Source Specimen fixture A Specimen fixture B Receiver or load IEC 1013/0
48、4 Figure A.1a Insertion technique Source Reference fixture (with specimen) Receiver or load Source Specimen fixture (without specimen) Receiver or load IEC 1014/04 Figure A.1b Reference fixture technique Figure A.1 Technique diagrams Page8 EN60512255:2004-21506-525 4002:CEI 12 V 0 + Test specimen a)
49、 b) 50 receiver Z 0= 50 c) Z 050 or R 1 R 2 R 2 R 1 50 receiversComponentsR 1 resistor 1 R 2 resistor 2 Z 0 characteristic impedance V 0 source voltage Minimum loss pad equations: R 1= 50 1 (Z o/ 50) 0,5R 1= Z o1 (50 / Z o ) 0,5R 2= Z o/ 1 (Z o/ 50) 0,5R 2= 50 / 1 (50 / Z o ) 0,5Figure A.2 Single-ended terminations IEC 1015/04 Page9
