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Teledyne API - T100 UV Fluorescence SO2 Analyzer  
A Primer on Electro-Static Discharge 
 
 
319 
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