Teledyne T360, Руководство по эксплуатации, Страница: 266 / 358

A Primer on Electro-Static Discharge Teledyne API Model T360/T360M Operation Manual
264
Table 9-1: Static Generation Voltages for Typical Activities
MEANS OF GENERATION 65-90% RH 10-25% RH
Walking across nylon carpet 1,500V 35,000V
Walking across vinyl tile 250V 12,000V
Worker at bench 100V 6,000V
Poly bag picked up from bench 1,200V 20,000V
Moving around in a chair padded
with urethane foam
1,500V 18,000V
9.2. HOW ELECTRO-STATIC CHARGES CAUSE DAMAGE
Damage to components occurs when these static charges come into contact with
an electronic device. Current flows as the charge moves along the conductive
circuitry of the device and the typically very high voltage levels of the charge
overheat the delicate traces of the integrated circuits, melting them or even
vaporizing parts of them. When examined by microscope the damage caused by
electro-static discharge looks a lot like tiny bomb craters littered across the
landscape of the component’s circuitry.
A quick comparison of the values in Table 9-1 with the those shown in the Table
9-2, listing device susceptibility levels, shows why
Semiconductor Reliability
News
estimates that approximately 60% of device failures are the result of
damage due to electro-static discharge.
Table 9-2: 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
07272B DCN6552