SP3220EBCY-L Datasheet, PDF (14/19 Pages) Sipex Corporation – High Speed +3.0V to +5.5V RS-232 Driver/Receiver Pair

RR_CC
DC Power
Source
SSWW11
RR_SS
CC_SS
SSWW22
Device
Under
Test
Figure 20. ESD Test Circuit for Human Body Model
The Contact Discharge Method applies the ESD
current directly to the EUT. This method was
devised to reduce the unpredictability of the
ESD arc. The discharge current rise time is
constant since the energy is directly transfered
without the air-gap arc. In situations such as
hand held systems, the ESD charge can be
directly discharged to the equipment from a
person directly discharged to the equipment.
The current is transferred on to the keypad or the
serial port of the equipment directly and then
travels through the PCB and finally to the IC.
The circuit models in Figure 20 and 21 repre-
sent the typical ESD testing circuits used for all
three methods. The C_S is initially charged with
the DC power supply when the first switch
(SW1) is on. Now that the capacitor is charged,
the second switch (SW2) is on while SW1
switches off. The voltage stored in the capacitor
is then applied through R_S, the current limiting
resistor, onto the device under test (DUT). In
ESD tests, the SW2 switch is pulsed so that the
device under test recives a duration of voltage.
R_CC
DC Power
Source
SW1
Contact-Discharge Module
R_SS
R_V
SW2
Device
C_SS
Under
Test
Figure 21. ESD Test Circuit for IEC1000-4-2
RS and RV add up to 330Ω for IEC1000-4-2.
Rev: A Date:12/11/03
SP3220EB/EU +3.0 to +5.0V RS-232 Transceivers
14
© Copyright 2002 Sipex Corporation