Engineering Definitions
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Electrostatic Discharge. ESD
Antistatic Material. A material having a surface resisitivity between 109 and 1014 ohms per square.
Antistatic Property. the reduction of triboelectrlc charge generation. Anti-static materials minimize the generation of static
charges. This property is not dependent upon material resistivity.
Catastrophic Failure. A failure resulting in the permanent loss of a
critical function.
Charged Device Model. [CDM] A model characterizing a particular ESD failure mechanism in which an item isolated from ground is charged and is subsequently discharged causing a short duration discharge pulse. One of three ESD models, refer to the chart below. The standard that defines CDM is; ESD STM5.3.1: Electrostatic Discharge Sensitivity Testing - Charged Device Model.
Classification of ESDS Parts.
ESD Class 1: Susceptible to damage from ESD voltages greater than O to 1,999 Volts.
ESD Class 2: Susceptible to damage from ESD voltages of 2,000 to 3,999 volts.
ESD Class 3: Susceptible to damage from ESD voltages of 4,000 to 15,999 volts.
ESD Class non-ESD Sensitive: Susceptible to damage from ESD voltages above 16,000 volts.
Note there are sub classifications, refer below right.
ESD MODEL
HBM; Human Body Model, HBM Definition
MM; Machine Model,
CDM; Charged Device Model

ESDS Models and Voltage Ranges
Device Type | Junction/Polarity |
Bipolar transistor (NPN) | E+ to B |
Bipolar transistor (PNP) | E- to B+ |
Junction FET's (N-channel) | G+ to S |
Junction FET's (P-channel) | G- to S+ |
MOSFET's (N- or P-channel) | G to S (both polarities) |
Gate protected FET's (P-channel) | G to S (both polarities) |
Rectifiers (hot carrier and schottky) | A- to K+ |
Thyristors | G to K (both polarities) |
Unijunctions | G to B1 (both polarities) |
Darlingtons | E to B (both polarities) |
Small signal diodes | A to K (both polarities) |
Conductive Material. A material having a maximum surface resisitivity of 105 ohms per square.