IEC1000-4-2

The IEC1000-4-2 standard covers ESD testing and per-

formance of finished equipment; it does not specifically

refer to integrated circuits. The MAX1488E helps you

design equipment that meets Level 4 (the highest level)

of IEC1000-4-2, without additional ESD-protection com-

ponents.

The major difference between tests done using the

Human Body Model and IEC1000-4-2 is higher peak

current in IEC1000-4-2. Because series resistance is

lower in the IEC1000-4-2 ESD test model (Figure 3a),

the ESD withstand voltage measured to this standard is

generally lower than that measured using the Human

Body Model. Figure 3b shows the current waveform for

the ±6kV IEC1000-4-2 Level 4 ESD Contact-Discharge

test.

The Air-Gap test involves approaching the device with

a charged probe. The Contact-Discharge method con-

nects the probe to the device before the probe is ener-

gized.

Machine Model

The Machine Model for ESD testing uses a 200pF stor-

age capacitor and zero-discharge resistance. Its objec-

tive is to mimic the stress caused by contact that

occurs with handling and assembly during manufactur-

ing. Of course, all pins (not just RS-232 inputs and out-

puts) require this protection during manufacturing.

Therefore, the Machine Model is less relevant to the I/O

ports than the Human Body Model and IEC1000-4-2.

__________Applications Information

Use proper layout to ensure other devices on your

board are not damaged in an ESD strike. Currents as

high as 60A can instantaneously pass into the ground,

so it is important to minimize the ground-lead return

path to the power supply. A separate return path to the

power supply is recommended. Trace widths should be

with 0.1µF capacitors as close to the part as possible to

ensure maximum ESD protection.

±15kV ESD-Protected, Quad, Low-Power

RS-232 Line Driver

_______________________________________________________________________________________

5

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

100pF

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 2a. Human Body ESD Test Model

90%

36.8%

TIME

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING

(NOT DRAWN TO SCALE)

Ir

10%

0

0

AMPERES

Figure 2b. Human Body Model Current Waveform

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

150pF

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 3a. IEC1000-4-2 ESD Test Model

30ns

60ns

t

100%

90%

10%

I

Figure 3b. IEC1000-4-2 ESD Generator Current Waveform