SP3243EUEA-L-TR Datasheet, PDF (17/25 Pages) Exar Corporation – 3 Driver/5 Receiver Intelligent +3.0V to +5.5V RS-232 Transceivers

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 IEC61000-4-2.
Figure 24. ESD Test Circuit for IEC61000-4-2
The circuit models in Figures 23 and 24 represent
the typical ESD testing circuit 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
receives a duration of voltage.
For the Human Body Model, the current limiting
resistor (R_S) and the source capacitor (C_S) are
1.5kΩ an 100pF, respectively. For IEC-61000-4-2,
the current limiting resistor (R_S) and the source ca-
pacitor (C_S) are 330Ω an 150pF, respectively.
The higher C_S value and lower R_S value in the
IEC61000-4-2 model are more stringent than the
Human Body Model. The larger storage capaci-
tor injects a higher voltage to the test point when
SW2 is switched on. The lower current limiting
resistor increases the current charge onto the
30A
15A
0A
t = 0ns
t = 30ns
t→
Figure 25. ESD Test Waveform for IEC61000-4-2
Device PIN
TESTED
Human Body
IEC61000-4-2
MODEL
Air Discharge Direct Contact
Driver Outputs
Receiver Inputs
+15kV
+15kV
+15kV
+15kV
+8kV
+8kV
Table 4. Transceiver ESD Tolerance Levels
Level
4
4
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
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SP3243E_102_060611