ADM483E
Rev. A | Page 12 of 16
ESD TESTING
Two coupling methods are used for ESD testing: contact
discharge and air-gap discharge. Contact discharge calls for a
direct connection to the unit being tested. Air-gap discharge
uses a higher test voltage but does not make direct contact with
the unit under test. With air-gap discharge, the discharge gun is
moved toward the unit under test, developing an arc across the
air gap. This method is influenced by humidity, temperature,
barometric pressure, distance, and rate of closure of the discharge
gun. The contact discharge method, though less realistic, is
more repeatable and is gaining acceptance and preference over
the air-gap method.
Although very little energy is contained within an ESD pulse,
the extremely fast rise time, coupled with high voltages, can
cause failures in unprotected semiconductors. Catastrophic
destruction may occur immediately as a result of arcing or
heating. Even if catastrophic failure does not occur immediately,
the device may suffer from parametric degradation, which can
result in degraded performance. The cumulative effects of
continuous exposure may eventually lead to complete failure.
C1
R2
HIGH
VOLTAGE
GENERATOR
DEVICE
UNDER TEST
ESD TEST METHOD
HUMAN BODY MODEL
R2
1.5kΩ
C1
100pF
06012-024
Figure 24. ESD Generator
I/O lines are particularly vulnerable to ESD damage. Simply
touching or plugging in an I/O cable can result in a static
discharge that may damage or completely destroy the interface
product connected to the I/O port.
It is, therefore, extremely important to have high levels of ESD
protection on the I/O lines.
It is possible that the ESD discharge could induce latch-up in
the device under test. Therefore, it is important that ESD testing
on the I/O pins be carried out while device power is applied.
This type of testing is more representative of a real-world I/O
discharge where the equipment is operating normally when the
discharge occurs.
100%
90%
36.8%
10%
TIME (
t
)
I
PEAK
t
RL
t
DL
06012-025
Figure 25. Human Body Model ESD Current Waveform
Table 8. ADM483E ESD Test Results
ESD Test Method I/O Pins
Human Body Model: Air ±15 kV
Human Body Model: Contact ±8 kV
