MAX202E–MAX213E,
MAX232E/MAX241E
±15kV ESD-Protected,
5V RS-232 Transceivers
R
C
1MΩ
CHARGE-CURRENT-
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
R
D
1500Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
I
P
100%
90%
AMPERES
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Cs
100pF
STORAGE
CAPACITOR
36.8%
10%
0
0
t
RL
TIME
t
DL
CURRENT WAVEFORM
Figure 6a. Human Body ESD Test Model
Figure 6b. Human Body Model Current Waveform
I
R
C
50MΩ to 100MΩ
CHARGE-CURRENT-
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
R
D
330Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
100%
90%
Cs
150pF
STORAGE
CAPACITOR
I
PEAK
10%
Figure 7a. IEC1000-4-2 ESD Test Model
t r = 0.7ns to 1ns
t
30ns
60ns
est, which is then discharged into the test device
through a 1.5kΩ resistor.
Figure 7b. IEC1000-4-2 ESD Generator Current Waveform
IEC1000-4-2
The IEC1000-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifically
refer
to
integrated
circuits.
The
MAX202E/MAX203E–MAX213E, MAX232E/MAX241E
help you design equipment that meets level 4 (the high-
est level) of IEC1000-4-2, without the need for addition-
al ESD-protection components.
The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
current in IEC1000-4-2, because series resistance is
lower in the IEC1000-4-2 model. Hence, the ESD with-
stand voltage measured to IEC1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 7b shows the current waveform for the
8kV IEC1000-4-2 level-four ESD contact-discharge test.
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method con-
nects the probe to the device before the probe is ener-
gized.
Machine Model
The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resis-
tance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protec-
tion during manufacturing, not just RS-232 inputs and
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