ADM485E/ADM487E/ADM1487E

Rev. B | Page 14 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 discharge, the discharge gun is moved

toward the unit under test, developing an arc across the air gap;

thus, the term air discharge is used. 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 can occur immediately as a result of arcing or heating.

Even if catastrophic failure does not occur immediately, the

device can suffer from parametric degradation, which can result

in degraded performance. The cumulative effects of continuous

exposure can eventually lead to complete failure.

C1

R2

HIGH

VOLTAGE

GENERATOR

DEVICE

UNDER TEST

NOTES:

1. THE ESD TEST METHOD USED IS THE

HUMAN BODY MODEL (±15kV)

WITH R2 = 1500

Ω AND C1 = 100pF.

Figure 27. 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 can 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.

The ESD discharge can 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)

tRL

tDL

Figure 28. Human Body Model ESD Current Waveform

Table 9. ADM483E ESD Test Results

ESD Test Method

I/O Pins

Other Pins

Human body model (HBM)

±15 kV

±3.5 kV