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A-ii GTECH Technical Training and Support Services
ESD HANDLING
All GTECH Printed Circuit Boards (PCBs) are static-sensitive. In order to prevent
damage to electronic components through ESD, please take the precautions
presented in this chapter whenever:
• Performing any work on a PCBs and equipment containing PCBs
• Removing subassemblies or components
What is ESD?
Static is the electrical charge created by the friction of two dissimilar materials
moving against each other. Electro Static Discharge, or ESD, is the unintended
dissipation of that charge, typically by short circuiting the charge to another
device or to ground.
Our bodies can create as much as 25,000 volts of static electricity across our 100
to 250 picofarads of capacitance to ground. In the worst case work environment,
voltages on some objects could exceed 50,000 volts. This more than exceeds the
static-tolerance threshold of most transistors, resistors, op-amps, and digital
computer chips. Some MOS families, for instance, can be damaged by a charge as
low as 150 volts.
Usually the damage is such that it goes undetected for some time but eventually
creates either an intermittent or hard failure in the field. Insulators, or non-
conductors of electricity, pose the greatest static discharge threat to electronic
devices because of their inability to bleed their static charges.
Becoming “Static Safe”
Equipment or component failures that result from ESD can be difficult to identify
but can be avoided at minimal cost with proper handling techniques.
A static electricity-safe workplace is an environment in which anything that can
generate static charges is eliminated or is drained of its charge. Such a workplace
employs conductive and static dissipative materials for its table tops, floor
surfaces, clothing, and material handling bins, boxes and bags. Machines, tools
and test fixtures should be properly grounded. Technicians or anyone handling
electronic components should wear wrist straps and even ankle straps at all times
when working on or near ESD sensitive electronic modules, PCBs and devices.
GTECH has created this chapter to help you identify ESD failures and to
implement correct handling procedures. Please read the following sections
carefully.