Nortel Networks DCT1900 manual Protection against Electrostatic Discharge ESD, ESD Handling

Technical Product Manual - DCT1900

Safety and Regulatory Information, Protection against Electrostatic Discharge (ESD)

CHAPTER 3

Protection against Electrostatic Discharge (ESD)

3.1General

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.

3.2ESD 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.

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