ASTM F1812-02
(Test Method)Standard Test Method for Determining the Effectiveness of Membrane Switch ESD Shielding
Standard Test Method for Determining the Effectiveness of Membrane Switch ESD Shielding
SIGNIFICANCE AND USE
Nearly all electronic devices are susceptible to possible damage or degradation from ESD encountered in their operating environments. The sensitivity of the equipment, the potential consequences of a malfunction, and the expected environmental conditions all impact the level of ESD protection needed.
ESD shielding effectiveness test may be destructive, and units that have been tested should be considered unreliable for future use.
SCOPE
1.1 This test method is used to determine the electrostatic discharge (ESD) shielding effectiveness of a membrane switch assembly. This test method may be used to test a membrane switch to destruction, that is, to determine its maximum ESD shielding effectiveness, or it may be used to test the ability of a membrane switch to withstand a predetermined level of exposure.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:F1812–02
Standard Test Method for
Determining the Effectiveness of Membrane Switch ESD
1
Shielding
This standard is issued under the fixed designation F 1812; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Interferences
1.1 This test method is used to determine the electrostatic 4.1 The following parameters may affect the results of this
discharge (ESD) shielding effectiveness of a membrane switch test:
assembly. This test method may be used to test a membrane 4.1.1 Temperature may affect the tendency of an ESD event
switch to destruction, that is, to determine its maximum ESD to occur,
shielding effectiveness, or it may be used to test the ability of 4.1.2 Relative humidity may affect the tendency of an ESD
a membrane switch to withstand a predetermined level of event to occur,
exposure. 4.1.3 Barometric pressure may affect the tendency of an
1.2 The values stated in SI units are to be regarded as the ESD event to occur, and
standard. The values given in parentheses are for information 4.1.4 The composition of the work bench may influence the
only. test results.
1.3 This standard does not purport to address all of the
5. Apparatus
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 5.1 Discharge Probe.
5.2 ESD Simulator—Commercially available device for
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. applying required or specified voltages, monitoring for ESD
event and selecting various voltage levels, and probes for
2. Terminology
contact or air discharge.
2.1 Definitions:
6. Procedure: Direct Application of Discharge
2.1.1 discharge pulse count—number of applied discharges.
6.1 Pretest Setup:
2.1.2 discharge pulse interval—time duration between ap-
plied voltage. 6.1.1 Place switch on a nonconductive surface, or as speci-
fied.
2.1.3 ESD (electrostatic discharge) event—detection of ap-
plied charge at input/output (I/O) points. 6.1.2 If applicable, connect the ESD shield, ground trace, or
ground plane to earth ground.
2.1.4 I/O points—specified conductive area, location, or
circuitry, typically all circuit paths, traces and wires. 6.1.3 Connect all circuitry pin inputs or outputs to the ESD
generating device’s ground.
3. Significance and Use
6.1.4 Ambient laboratory conditions to be within:
3.1 Nearly all electronic devices are susceptible to possible 6.1.4.1 Relative humidity 30 to 60 %,
damage or degradation from ESD encountered in their operat- 6.1.4.2 Temperature 15 to 35°C, and
ing environments. The sensitivity of the equipment, the poten- 6.1.4.3 Atmospheric pressure 680 to 1060 mbar or other-
tial consequences of a malfunction, and the expected environ- wise specified.
mental conditions all impact the level of ESD protection 6.2 In Process:
needed. 6.2.1 Accumulationofchargeonthemembraneswitchmust
3.2 ESD shielding effectiveness test may be destructive, and be dissipated between successive tests.
units that have been tested should be considered unreliable for 6.2.2 Set the initial voltage level to 2Kv. Set discharge pulse
future use. interval as specified.
6.2.3 Place discharge tip perpendicular, and in contact, with
switch surface at the specified point.
1
This test method is under the jurisdiction of ASTM Committee F01 on
6.2.4 Trigger the ESD discharge and monitor.
Electronics and is the direct responsibility of Subcommittee F01.18 on Membrane
6.2.5 Check the ESD discharge event to I/O points.
Switches.
Current edition approved Dec. 10, 2002. Published February 2003. Originally
approved in 1997. Last previous edition approved in 1997 as F 1812–97a.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F1812–02
6.2.6 If no ESD event occurs, discharge accumulated volt- 7.2.4 Check for ESD discharge event at specified I/O points.
age on surface to earth ground. 7.3 If no ESD event occurs, discharge accumulated voltage
6.2.7 Reset and increase test voltage to next level in on surface to earth ground.
accordance with Table 1 (or as specified). Repeat 6.2.3-6.3. 7.3.1 Reset and increase test voltage to next level in
6.3 If ESD discharge event is noted, report and terminate accordance with Table1(oras specified). Repeat 7.2.1-7.4.
test. 7.4 If ESD discharge event is noted, report and terminate
6.4 Repeat 6.2.1-6.3 for other test points. test.
7.5 Repeat 7.1.1-7.1.4 for other test points.
7. Procedure: Air Gap Discharge
8. Repor
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