7

Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

© Copyright 2003 Sipex Corporation

The Human Body Model has been the generally

accepted ESD testing method for semiconductors.

This method is also specified in MIL-STD-883,

Method 3015.7 for ESD testing. The premise of

this ESD test is to simulate the human body’s

potential to store electro-static energy and

discharge it to an integrated circuit.

The

simulation is performed by using a test model as

shown in Figure 7. This method will test the

IC’s capability to withstand an ESD transient

during normal handling such as in manufacturing

areas where the ICs tend to be handled frequently.

The IEC-1000-4-2, formerly IEC801-2, is

generally used for testing ESD on equipment and

systems. For system manufacturers, they must

guarantee a certain amount of ESD protection

since the system itself is exposed to the outside

environment and human presence. The premise

with IEC1000-4-2 is that the system is required

to withstand an amount of static electricity when

ESD is applied to points and surfaces of the

equipment that are accessible to personnel during

normal usage. The transceiver IC receives most

of the ESD current when the ESD source is

applied to the connector pins. The test circuit for

IEC1000-4-2 is shown on Figure 8. There are

two methods within IEC1000-4-2, the Air

Discharge method and the Contact Discharge

method.

R

C

C

S

R

S

SW1

SW1

SW2

SW2

Device

Under

Test

DC Power

Source

SW1

SW2

Figure 7. ESD Test Circuit for Human Body Model

R

RS

S and

and R

RV

V add up to 330

add up to 330Ω

Ω ffor IEC1000-4-2.

or IEC1000-4-2.

RS and RV add up to 330Ω for IEC1000-4-2.

Contact-Discharge Module

Contact-Discharge Module

R

V

R

C

C

S

R

S

SW1

SW1

SW2

SW2

Device

Under

Test

DC Power

Source

SW1

SW2

Contact-Discharge Module

Figure 8. ESD Test Circuit for IEC1000-4-2