1、Designation: B 878 97 (Reapproved 2009)Standard Test Method forNanosecond Event Detection for Electrical Contacts andConnectors1This standard is issued under the fixed designation B 878; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes equipment and techniquesfor detecting contact resistance transients yieldin
3、g resistancesgreater than a specified value and lasting for at least a specifiedminimum duration.1.2 The minimum durations specified in this standard are 1,10, and 50 nanoseconds (ns).1.3 The minimum sample resistance required for an eventdetection in this standard is 10 V.1.4 An ASTM guide for meas
4、uring electrical contact tran-sients of various durations is available as Guide B 854.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associate
5、d with its use. It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet (MSDS) for this product/materialas provided by the manufacturer, to establish appropriatesafety and health practices, and de
6、termine the applicability ofregulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B 542 Terminology Relating to Electrical Contacts andTheir UseB 854 Guide for Measuring Electrical Contact Intermit-tences2.2 Other Standards:IEC 801-2 ed 2:913EN 50 082-1:9433. Terminology3.1
7、Definitions: Many terms used in this standard aredefined in Terminology B 542.3.2 Definitions of Terms Specific to This Standard:3.2.1 event, na condition in which the sample resistanceincreases by more than 10 V for more than a specified timeduration.4. Significance and Use4.1 The tests in this tes
8、t method are designed to assess theresistance stability of electrical contacts or connections.4.2 The described procedures are for the detection of eventsthat result from short duration, high-resistance fluctuations, orof voltage variations that may result in improper triggering ofhigh speed digital
9、 circuits.4.3 In those procedures, the test currents are 100 mA (620mA) when the test sample has a resistance between 0 and 10 V.Since the minimum resistance change required to produce anevent (defined in 3.2.1) is specified as 10 V (see 1.3), thevoltage increase required to produce this event must
10、be at least1.0 V.4.4 The detection of nanosecond-duration events is consid-ered necessary when an application is susceptible to noise.However, these procedures are not capable of determining theactual duration of the event detected.4.5 The integrity of nanosecond-duration signals can onlybe maintain
11、ed with transmission lines; therefore, contacts inseries are connected to a detector channel through coaxialcable. The detector will indicate when the resistance monitoredexceeds the minimum event resistance for more than thespecified duration.4.6 The test condition designation corresponding to a sp
12、e-cific minimum event duration of 1, 10, or 50 ns is listed inTable 1. These shall be specified in the referencing document.5. Apparatus5.1 DetectorThe detector used shall be an AnaTech 64EHD, 32 EHD, or equivalent. The detector shall meet thefollowing requirements:5.1.1 Electromagnetic Interference
13、 (EMI)The detectorshall pass the European Community (EC) electrostatic dis-charge (ESD) requirement for computers (EN 50 082-1:941This test method is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.11 on Electrical Conta
14、ct Test Methods.Current edition approved April 15, 2009. Published April 2009. Originallyapproved in 1997. Last previous edition approved in 2003 as B 878 - 97 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
15、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
16、West Conshohocken, PA 19428-2959, United States.based on IEC 801-2, ed. 2:91). The performance criteria is “1)normal performance within the specification limits;” that is, nochannel is allowed to trip. Air discharge voltages shall include2, 4, 8, and 15 kV. Contact discharge voltages shall include 2
17、,4, 6, and 8 kV. Detector inputs shall be protected with coaxialshorts.5.1.2 dc CurrentEach channel shall supply 100 6 20 mAwhen the sample being tested has a resistance between 0 and 10V.5.1.3 Input Impedance:5.1.3.1 Direct Current (dc)The detector source resistance(impedance) shall be 50 V when th
18、e sample resistance isbetween 0 and 10 V.5.1.3.2 RF Input ImpedanceA Time Domain Reflectome-ter (TDR) or Network Analyzer Time Domain Reflectometer(NATDR) shall be used to measure the reflection in percent ofa (simulated) 0.5 ns risetime step when the sample directcurrent resistance is 10 V and the
19、detector current is 100 mA.(The 10 V sample resistance is put on the bias port forNATDR.) An acceptable detector shall reflect less than 30 %amplitude.5.1.4 Amplitude SensitivityAmplitude required to trip thedetector with a 1 nanosecond duration pulse shall be no morethan 120 % of the direct current
20、 trip amplitude. One nanosec-ond pulse duration shall be measured at 90 % of the pulseamplitude, and the rise and fall times shall be less than 0.5 ns.Pulse low level shall be 0 V. These shall be measured with a 1GHz bandwidth oscilloscope and a pulse generator (see Fig. 1).5.1.4.1 The same requirem
21、ents shall be met for the 10 and50 ns detector settings, but the pulse rise and fall times can nowbe less than 2 ns.5.1.5 AccuracyIt shall be possible to adjust the detector totrip at 10 6 1 V for all channels in use.5.2 Test SetupRecommended equipment is as shown inFig. 2. A short flexible ground s
22、trap directs ground loopcurrents away from the sample (see Fig. 2, Note E). TheRG-223 coaxial cable is well shielded whereas the short 50 Vminiature coaxial cable is flexible. Each EMI loop is connectedto a detector channel and is used as a control.5.3 Sample and EMI Loop PreparationThe sample circu
23、itshall have a resistance of less than 4 V.5.3.1 Sample Wiring:5.3.1.1 A contact or series-wired contacts (see Fig. 3, NoteA) shall be wired from the center conductor to the braid ofminiature 50-V coaxial cable (see Fig. 2, Note C).5.3.1.2 The sample, as wired to the miniature coaxial cablefor testi
24、ng, shall be capable of passing short duration pulses. Atime domain reflectometer (TDR) shall be used to measure thetransition time of a fast risetime step (25 mm wide (see 7.3).F Strain relief coaxial cable at these locations.G Physical support for patch panel.H RG-223 double braid coaxial cable.FI
25、G. 2 Ten and Fifty Nanosecond FixturingB 878 97 (2009)2shall be connected to the metal fixturing as close to theconnector-under-test as possible. This connection shall be asshort as possible and perpendicular to nearby sample conduc-tors (see Fig. 3, Note D). This is done for the sample channelsonly
26、, not the control channels.NOTE 1If there is no metal fixturing within 5 cm of the sample circuit,all connections to metal fixturing in this standard may be ignored.5.3.2.2 Large EMI currents in adjacent contacts can couplethrough crosstalk or capacitance to monitored channels. Toreduce this, no con
27、ductor of any type may be connected tocontacts not being monitored for the event. It is recommendedthat monitored contacts be evenly distributed around theconnector to minimize crosstalk with other monitored channels(see Fig. 3, Note B).5.3.2.3 The loop area of the sample circuits shall be mini-mize
28、d to reduce magnetic field coupling.5.3.3 Control Channel(s)Anytime a failure is indicated, itis possible that the real cause was actually electromagneticinterference (EMI), and not the connector-under-test. The goalof the control channel(s) is to detect EMI at levels much lowerthan required to trig
29、ger an event on a sample channel. Duringtesting, the control channels shall be monitored with the samedetector values as used on the sample circuits. An eventobserved on a control channel invalidates any other eventsdetected during the polling period. See 7.6 to define pollingperiod.6. Preliminary P
30、rocedures6.1 For Test Conditions B and C (Ten and Fifty nanosec-onds, respectively):6.1.1 A control channel shall consist of a separate loop ofwire with an area of one square meter suspended above thesample(s) and monitored through a miniature coaxial cableattached at the top center of the loop (see
31、 Fig. 2, Notes A andB).6.1.2 Find the series wired circuit with the greatest capaci-tance to the fixturing metal, measured without any coaxialcable attached. Instead of connecting this to a miniature coaxialcable, connect it to the center of the control channel loop,opposite the coaxial cable connec
32、tion (see Fig. 2, Note B). Aseparate sample may be required if the sample has only onecontact.6.2 For Test Condition A (One nanosecond):6.2.1 Three control channels shall be provided, consisting of3 nested, mutually perpendicular loops (see Fig. 5). Each loopshall have a nominal area of 36 square cm
33、 (for example, 6 3 66 0.5 cm). These loops shall be suspended over the sample(s).6.2.2 Find the series-wired circuit with the greatest capaci-tance to the fixturing metal, measured without any coaxialcable attached. Instead of connecting this to a miniature coaxialNOTE 1A Series-wired contacts (see
34、5.3.1).B Contacts skipped to reduce crosstalk (see 5.3.2.2).C The circuit with maximum capacitance to fixture (see 6.1.1).D The very short miniature coaxial cable ground (see 5.3.2.1).FIG. 3 Example of Series-Wired SampleNOTE 1Requirement is that Point 2Point 1 minimum event dura-tion from Fig. 1.FI
35、G. 4 TDR Measurement Trace of Sample CircuitFIG. 5 One Nanosecond Fixturing with Nested 6 3 6cmEMILoops (see 6.2.1)B 878 97 (2009)3cable, connect it to the center of one of the control channelloops, opposite the coaxial cable connection.Aseparate samplemay be required if the sample has only one cont
36、act.7. Procedure7.1 Prepare samples and measure the fall time per 5.3.1.2,using TDR. If this requirement cannot be met, fewer contactsin series or better fixture wiring may be required.7.2 Place the EMI loop(s) of 5.3.3 over the sample andconnect to the sample circuit with the greatest capacitance.7
37、.3 Assemble the equipment as indicated in Fig. 2 (or Fig. 5for one nanosecond). The 50 V miniature coaxial cable andespecially the ground strap shall be kept as short as practical(see Fig. 2, Note E). Additionally, the miniature coaxial cableground connection to connector shell or metal fixturing, o
38、rboth, shall be as short as possible and perpendicular to nearbysample conductors (see 5.3.2.1 and Fig. 3).7.4 Turn on the equipment. Set the equipment to deliver 1006 20 mA. Also set the detector to trip at 10 V above the initialresistance. Reset all channels. If the Detail Specificationspecifies u
39、sing a current less than 80 mA or a thresholdresistance less than 10 V, it may be necessary to add additionalshielding, or to locate the test equipment in a shielded room orbox.7.5 Disconnect each sample from the detector by unmatingthe coaxial connectors. Confirm that the indicator trips whendiscon
40、nected, as a functional check.7.6 Apply the desired environmental stress to the connector-under-test. The test should be broken up into equal-length timeperiods. At the end of each, the status of each channel shouldbe polled. Any events detected during a polling period whichalso registers an event o
41、n a control channel shall be consideredEMI induced (not a connector failure).7.7 At the end of testing, the failure indications at differentpolling times should be analyzed for patterns suggesting EMI,such as simultaneous events in different channels.8. Report8.1 In reporting the results of the test
42、, the following infor-mation shall be given:8.1.1 Contact positions tested on each channel.8.1.2 Connectors tested.8.1.3 Sample lead dress description (for example, how is theconnection made between the coaxial cable and the sampleconductors, or how is the wiring accomplished between sampleconductor
43、s in series, etc.) or diagram.8.1.4 EMI event history, detected on the EMI loop.8.1.5 Environmental stresses applied.8.1.6 Detected event history for each channel.8.1.7 TDR results on sample setup verification.8.1.8 Name of operator and date of test.NOTE 2The following details shall be specified in
44、the referencingdocument:(a) Samples and contacts to be tested.(b) 1, 10, or 50 ns minimum duration.(c) Resistance increase, if other than 10 V.(d) Current, if other than 100 mA.9. Precision and Bias9.1 PrecisionTest precision is determined by detectorperformance. One unit was evaluated which consist
45、ed of 64detectors. In the 50 ns position, the duration sensitivity rangedbetween 45.4 and 51.0 ns (pulse amplitude twice the dc tripvalue). In the 10 ns position, it ranged between 8.5 and 9.7 ns.In the 1 ns position,a1nspulse tripped two detectors whenthey had a peak amplitude equal to the dc trip
46、voltage (otherchannels not tested). Thus, voltage amplitude sensitivity didnot change between dc and the shortest duration of this teststandard. All 64 channels were checked for the same using a1.9 ns duration (90 % amplitude) pulse. The total variation was63%.9.2 BiasThis standard requires the dete
47、ctor to have asample current tolerance and a given minimum (voltage)amplitude sensitivity to each event duration (see 5.1). The mostsignificant possible errors will be EMI-produced false failureindications. Since each test location will have a different EMIenvironment, such errors will be impossible
48、 to predict pre-cisely.10. Keywords10.1 event detection; nanosecond events; nanosecondintermittencesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that dete
49、rmination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which y
