ASTM F1812-2009 Standard Test Method for Determining the Effectiveness of Membrane Switch ESD Shielding《测定薄膜开关ESD屏蔽有效性的标准试验方法》.pdf

1、Designation: F 1812 09Standard Test Method forDetermining the Effectiveness of Membrane Switch ESDShielding1This standard is issued under the fixed designation F 1812; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las

2、t 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 is used to determine the electrostaticdischarge (ESD) shielding effectiveness of a membrane switchassemb

3、ly. This test method may be used to test a membraneswitch to destruction, that is, to determine its maximum ESDshielding effectiveness, or it may be used to test the ability ofa membrane switch to withstand a predetermined level ofexposure.1.2 The values stated in SI units are to be regarded as thes

4、tandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appl

5、ica-bility of regulatory limitations prior to use2. Terminology2.1 Definitions:2.1.1 discharge pulse countnumber of applied discharges.2.1.2 discharge pulse intervaltime duration between ap-plied voltage.2.1.3 ESD (electrostatic discharge) eventdetection of ap-plied charge at input/output (I/O) poin

6、ts.2.1.4 I/O pointsspecified conductive area, location, orcircuitry, typically all circuit paths, traces and wires.3. Significance and Use3.1 Nearly all electronic devices are susceptible to possibledamage or degradation from ESD encountered in their operat-ing environments. The sensitivity of the e

7、quipment, the poten-tial consequences of a malfunction, and the expected environ-mental conditions all impact the level of ESD protectionneeded.3.2 ESD shielding effectiveness test may be destructive, andunits that have been tested should be considered unreliable forfuture use.4. Interferences4.1 Th

8、e following parameters may affect the results of thistest:4.1.1 Temperature may affect the tendency of an ESD eventto occur,4.1.2 Relative humidity may affect the tendency of an ESDevent to occur,4.1.3 Barometric pressure may affect the tendency of anESD event to occur, and4.1.4 The composition of t

9、he work bench may influence thetest results.5. Apparatus5.1 Discharge Probe.5.2 ESD SimulatorCommercially available device forapplying required or specified voltages, monitoring for ESDevent and selecting various voltage levels, and probes forcontact or air discharge.6. Procedure: Direct Application

10、 of Discharge6.1 Pretest Setup:6.1.1 Place switch on a nonconductive surface, or as speci-fied.6.1.2 If applicable, connect the ESD shield, ground trace, orground plane to earth ground.6.1.3 Connect all circuitry pin inputs or outputs to the ESDgenerating devices ground.6.1.4 Ambient laboratory cond

11、itions to be within:6.1.4.1 Relative humidity 30 to 60 %,6.1.4.2 Temperature 15 to 35C, and6.1.4.3 Atmospheric pressure 680 to 1060 mbar or other-wise specified.6.2 In Process:6.2.1 Accumulation of charge on the membrane switch mustbe dissipated between successive tests.6.2.2 Set the initial voltage

12、 level to 2Kv. Set discharge pulseinterval as specified.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved June 15, 2009. Published August 2009. Originallyapproved in 199

13、7. Last previous edition approved in 2002 as F 1812-02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2.3 Place discharge tip perpendicular, and in contact, withswitch surface at the specified point.6.2.4 Trigger the ESD discharge

14、 and monitor.6.2.5 Check the ESD discharge event to I/O points.6.2.6 If no ESD event occurs, discharge accumulated volt-age on surface to earth ground.6.2.7 Reset and increase test voltage to next level inaccordance with Table 1 (or as specified). Repeat 6.2.3-6.3.6.3 If ESD discharge event is noted

15、, report and terminatetest.6.4 Repeat 6.2.1-6.3 for other test points.7. Procedure: Air Gap Discharge7.1 Pretest Setup:7.1.1 Position switch on a nonconductive surface, or asspecified.7.1.2 If applicable, connect the ESD shield, ground trace, orground plane to earth ground.7.1.3 Connect all circuitr

16、y pin in or outputs to the ESDgenerating devices ground.7.1.4 Ambient laboratory conditions to be within:7.1.4.1 Relative humidity to be between 30 to 60 %,7.1.4.2 Temperature 15 to 35C, and7.1.4.3 Atmospheric Pressure 680 to 1060 mbar or other-wise specified.7.2 In Process:7.2.1 Set the initial vol

17、tage level to 2Kv. Set discharge pulseinterval as specified.7.2.2 Place contact air discharge tip 2 in. (50.8 mm) awayfrom, and perpendicular to switch surface at the specified point.7.2.3 Trigger the ESD discharge and monitor.7.2.4 Check for ESD discharge event at specified I/O points.7.3 If no ESD

18、 event occurs, discharge accumulated voltageon surface to earth ground.7.3.1 Reset and increase test voltage to next level inaccordance with Table 1 ( or as specified). Repeat 7.2.1-7.4.7.4 If ESD discharge event is noted, report and terminatetest.7.5 Repeat 7.1.1-7.1.4 for other test points.8. Repo

19、rt8.1 Report the following information:8.1.1 Humidity,8.1.2 Temperature,8.1.3 Atmospheric pressure,8.1.4 Description of I/O points,8.1.5 Description of apparatus,8.1.6 Description of test points,8.1.7 Description of unit under test (UUT),8.1.8 Maximum voltage data,8.1.9 Type of test (contact or air)

20、,8.1.10 Physical description of damage (if applicable),8.1.11 Date,8.1.12 Time,8.1.13 Operator,8.1.14 Discharge pulse count,8.1.15 Discharge pulse interval, and8.1.16 Description of probe.9. Precision and Bias9.1 PrecisionIt is not possible to specify the precision ofthe procedure in Test Method F 1

21、812 for measuring ESDbecause inter-laboratory studies have proven inconclusive dueto insufficient participating laboratories with the appropriateequipment.9.2 BiasNo information can be presented on the bias ofthe procedure in Test Method F 1812 for measuring ESDbecause no standard sample is availabl

22、e for this industry.10. Keywords10.1 ESD; membrane switch; shieldingASTM 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 determination of the validity of any

23、 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 in

24、vited 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 you may attend. If you feel that your comments have not receive

25、d a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Voltage LevelsContact Air2Kv 2Kv4Kv 4Kv6Kv 8Kv8Kv 15KvF1812092