SP481E_07 Datasheet, PDF (7/11 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 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.
RR_CC
DC Power
Source
SSWW11
RR_SS
CC_SS
SSWW22
Device
Under
Test
Figure 7. ESD Test Circuit for Human Body Model
RR_CC
DC Power
Source
SSWW11
Contact-Discharge Module
RR_SS
R_V
SSWW22
Device
CC_SS
Under
Test
RS and RV add up to 330Ω for IEC1000-4-2.
Figure 8. ESD Test Circuit for IEC1000-4-2
May11-2007
SP481E Low Power Half-Duplex RS485 Transceivers
7
© 2007 Sipex Corporation