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3 Prevention of Electro Static
Discharge (ESD) to
Electrostatically Sensitive (ES)
Devices
Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-
effect transistorsand semiconductor "chip" components. The following techniques should be used to help reduce the
incidence of component damage caused by electro static discharge (ESD).
1.
Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any
ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available
dischargingESD wrist strap, which should be removed for potential shock reasons prior to applying power to the
unit under test.
2.
After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such
as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.
3.
Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4.
Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static (ESD
protected)" can generate electrical charge sufficient to damage ES devices.
5.
Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.
6.
Do not remove a replacement ES device from its protective package until immediately before you are ready to
install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam,
aluminum foil or comparableconductive material).
7.
Immediately before removing the protective material from the leads of a replacement ES device, touch the
protective material to the chassis or circuit assembly into which the device will be installed.
Caution
Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8.
Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise harmless motion such
as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static
electricity (ESD)sufficient to damage an ES device).
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