SP3220E_05 Datasheet, PDF (14/21 Pages) Sipex Corporation – +3.0V to +5.5V RS-232 Driver/Receiver Pair

ESD TOLERANCE
The SP3220E/EB/EU device incorporates rugge-
dized ESD cells on all driver output and receiver
input pins. The ESD structure is improved over our
previous family for more rugged applications and
environments sensitive to electro-static
discharges and associated transients. The im-
proved ESD tolerance is at least ±15kV without
damage nor latch-up.
There are different methods of ESD testing ap-
plied:
a) MIL-STD-883, Method 3015.7
b)IEC1000-4-2 Air Discharge
c)IEC1000-4-2 Direct Contact
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 20. 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 gener-
ally used for testing ESD on equipment and system
manufacturers; they must guarantee a certain
amount of ESD protection since the system itself is
RR_CC
SSWW11
DC Power
Source
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 IEC-1000-4-2 is shown in Figure 21.
There are two methods within IEC-4-2: the Air
Discharge method and the Contact Discharge
method.
With the Air Discharge Method, an ESD voltage is
applied to the equipment under test (EUT) through
air. This simulates an electrically charged person
ready to connect a cable onto the rear of the
system only to find an unpleasant zap just before
the person touches the back panel. The high
energy potential on the person discharges through
an arcing path to the rear panel system before he
or she even touches the system. This energy,
whether discharged directly or through air, is pre-
dominantly a function of the discharge current
rather than the discharge voltage.
Variables with an air discharge -- such as ap-
proach speed of the object carrying the ESD
potential to the system and humidity -- will tend to
change the discharge current. For example, the
rise time of the discharge current varies with the
approach speed.
RR_SS
CC_SS
SSWW22
Device
Under
Test
Figure 20. ESD Test Circuit for Human Body Model
Date: 8/22/05
Date: 8/30/05
SP3220E/EB/EU High ESD RS-232 Driver/Receiver
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SP3220E/EB/EU High ESD RS-232 Driver/Receiver
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© Copyright 2005 Sipex Corporation
© Copyright 2005 Sipex Corporation