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Transient Protection Technology
Susceptibility / Immunity
Equipment with external connections is susceptible to electrical damage from a variety of energy sources. These electrical connections provide a path for excess energy to damage sensitive circuits.
Electronic components are inherently vulnerable to damage from man made and natural high voltage and/or high energy sources, such as electrostatic discharge, lightning, and nuclear electromagnetic pulses. As higher density and higher speed devices are introduced, silicon feature size decreases. The level of voltage and energy required to destroy components also decreases.
The choice to protect equipment involves many parameters.This table shows some typical driving forces.
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Protection Driving Force
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Typical Examples
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Economic
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Cost of downtime, cost of repair
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Personal Safety
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Equipment operators during exposure
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Security/Safety
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Police, fire, military, intrusion systems
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Customer Requirements
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Commercial and military standards
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The Electromagnetic Environment
The electrical characteristics of some typical sources of transients are shown below.
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Electrical Source
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Typical Number/Year
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Electrical Energy
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Energy Frequency (Hz)
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Unique Risk Factors
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Lightning
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10-100
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High
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10k - 1M
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Geographic Location
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Electro-Static Discharge
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10-1000
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Very low
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10M-500M
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Handling of product
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Power Line Faults
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.1-1
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Very high
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50/60
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Power wiring practices
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Nuclear Electro-Magnetic Pulse
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0-50
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Moderate
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1M-10M
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Global Politics
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Lightning energy can couple into a wiring system on coax, power, and ground conductors, and through building structural members as shown in the diagram. Lightning current usually flows simultaneously into grounding systems, through the coaxial port protector, and in the power and grounding wiring system. Predicting the origin of the transient and the current flow paths can be very difficult.
Therefore, effective protectors must stop transients originating from either side of the protector. It is also important that all conductive connections share a common ground to achieve effective transient protection. Remember, for complete protection of equipment all power and other wiring interfaces must be protected
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