SP481E Datasheet, PDF (8/12 Pages) Sipex Corporation – Enhanced Low Power Half-Duplex RS-485 Transceivers

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 9. This method will test the IC’s
capability to withstand an ESD transient dur-
ing normal handling such as in manufactur-
ing 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 guar-
antee 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 cir-
cuit for IEC1000-4-2 is shown on Figure 10.
There are two methods within IEC1000-4-2,
the Air Discharge method and the Contact
Discharge method.
R_C
DC Power
Source
SW1
R_S
C_S
SW2
Device
Under
Test
Figure 9. ESD Test Circuit for Human Body Model
R_C
DC Power
Source
SW1
Contact-Discharge Model
R_S
R_V
SW2
C_S
Device
Under
Test
RS and RV add up to 330Ω for IEC1000-4-2.
Figure 10. ESD Test Circuit for IEC1000-4-2
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com

SP481E,485E_100_121808