AN055
ESD Static Protection Manual
5
1.
Prevention of ESD/EOS
Electrostatic discharge ESD is a phenomenon in which electrostatic charge is rapidly
transferred between objects with different potentials generated by two electrostatic sources.
Electrostatic charges can cause damage to electrostatically sensitive devices when they
come into contact with or near them.
Electrical overstress EOS is an inherent result of component damage caused by harmful
electrical energy effects. There are many sources of EOS damage, such as: large current and
high voltage caused by lightning strikes/surges, ESD generated by electrical equipment or
operation/processing.
ESD-sensitive components are those that are susceptible to such high-energy discharges.
The relative sensitivity of components to ESD depends on their process. The smaller the
technologies
of the component, the faster the operation speed, and the more serious the
ESD sensitivity. For example, The high-speed IO and RF pins of MCU are easily damaged by
ESD.
Improper operating or handling can result in failure of ESD sensitive components or changes
in device performance. These failures may occur immediately or latently. Immediate failure
results can be individually tested, reworked, or scrapped. The consequences of latent failure
are the most serious. That is, the product has passed inspection and functional testing. It is
still possible that it will expire after delivery to the customer.
It is important to protect ESD sensitive components in circuit designs and packaging. Some
unprotected electronics/fixtures are often used in manufacturing and assembly areas to
connect ESD sensitive devices. Remember that ESD sensitive chips can only be removed
from the antistatic packaging on an EOS/ESD safe operating platform in the ESD protected
area EPA. This article will detail how to operate safely as a protected electronic assembly.
1.1.
Electrostatic Discharge ESD
If ESD damage does occur, the best protection method is to prevent static electricity from
being generated, and the second is to eliminate static electricity. The principles of all ESD
protection technologies and products are based on either or both of the above.
ESD damage is the result of the charge generated by electrostatic sources approaching or
touching ESD-sensitive components, which can be seen everywhere around us. The strength
of static electricity depends on the characteristics of the electrostatic source, and the
generation of static electricity requires the relative motion of objects, such as contact,
separation, and friction of objects.
The culprit for electrostatic discharge is the insulating material, because the insulating
material collects the electrostatic charge generated or acquired without allowing it to diffuse
from the surface of the material, refer to
Table 1-1. Common Static Sources
. Common
