Chapter 3, Protection against electrostatic discharge (esd), 1 general – Nortel Networks DCT1900 User Manual
Page 15: 2 esd handling, 3protection against electrostatic discharge (esd)
Technical Product Manual - DCT1900
Safety and Regulatory Information, Protection against Electrostatic Discharge (ESD)
Safety-DCT1900/R8/mw
3-1
© 2000-2005
C
HAPTER
3
Protection against Electrostatic Discharge (ESD)
3.1
General
Integrated circuits are sensitive to ESD.
To avoid damage caused by ESD, service engineers and other people must handle equipment and
boards carefully.
Electronic equipment has become more resistive to ESD, but we see an increase of situations
where static electricity can build up. This is caused by an increasing application of man–made
fibers like nylon, acrylic, etc. which are capable of generating ESD of 10,000 Volts and more.
Walking across a nylon carpet, even for a few feet, could cause a person to be charged–up to
more than 10,000 Volts. Under these conditions, if a system board or a (C)MOS device is touched
it could easily be damaged. Although the device may not be totally defective, it is often degraded,
causing it to fail at a later date without apparent reason.
To make sure that equipment and parts are well protected during shipment, special packaging
materials are utilized. System boards will be shipped in anti–static bags and (C)MOS devices and
other sensitive parts in small shielded boxes.
3.2
ESD Handling
In the interest of quality and reliability, it is advisable to observe the following rules when handling
system boards and parts.
1.
Service personnel should ground themselves by using a wrist strap when exchanging system
boards in a cabinet.
2.
Keep system boards and sensitive parts in their protective packaging until they are needed.
3.
When returning system boards or parts like EEPROMS to the factory, use the protective
packaging as described.
4.
Never underestimate the damaging power ESD can have and be especially careful when
temperatures are below freezing point and during very warm weather in combination with low
humidity. Make sure that the environmental conditions remain within the limits specified in
Section 3, "Product Specifications" in this book.