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Teledyne API - T100 UV Fluorescence SO2 Analyzer A Primer on Electro-Static Discharge
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Table 14-2: Sensitivity of Electronic Devices to Damage by ESD
DAMAGE SUSCEPTIBILITY VOLTAGE RANGE
DEVICE
DAMAGE BEGINS OCCURRING AT CATASTROPHIC DAMAGE AT
MOSFET 10 100
VMOS 30 1800
NMOS 60 100
GaAsFET 60 2000
EPROM 100 100
JFET 140 7000
SAW 150 500
Op-AMP 190 2500
CMOS 200 3000
Schottky Diodes 300 2500
Film Resistors 300 3000
This Film Resistors 300 7000
ECL 500 500
SCR 500 1000
Schottky TTL 500 2500
Potentially damaging electro-static discharges can occur:
Any time a charged surface (including the human body) discharges to a device. Even
simple contact of a finger to the leads of a sensitive device or assembly can allow
enough discharge to cause damage. A similar discharge can occur from a charged
conductive object, such as a metallic tool or fixture.
When static charges accumulated on a sensitive device discharges from the device to
another surface such as packaging materials, work surfaces, machine surfaces or other
device. In some cases, charged device discharges can be the most destructive.
A typical example of this is the simple act of installing an electronic assembly
into the connector or wiring harness of the equipment in which it is to function.
If the assembly is carrying a static charge, as it is connected to ground a discharge
will occur.
Whenever a sensitive device is moved into the field of an existing electro-static field,
a charge may be induced on the device in effect discharging the field onto the device.
If the device is then momentarily grounded while within the electrostatic field or
removed from the region of the electrostatic field and grounded somewhere else, a
second discharge will occur as the charge is transferred from the device to ground.
14.3. COMMON MYTHS ABOUT ESD DAMAGE
I didn’t feel a shock so there was no electro-static discharge: The human nervous
system isn’t able to feel a static discharge of less than 3500 volts. Most devices are
damaged by discharge levels much lower than that.
I didn’t touch it so there was no electro-static discharge: Electro-static charges
are fields whose lines of force can extend several inches or sometimes even feet away
from the surface bearing the charge.
06807C DCN6650