MAX241E Maxim Integrated Products, MAX241E Datasheet - Page 12

• Manufacturer Part Number: MAX241E
• Description: +5V RS-232 Transceivers
• Manufacturer: Maxim Integrated Products

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The IEC1000-4-2 standard covers ESD testing and
performance 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
highest level) of IEC1000-4-2, without the need for
additional 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
withstand 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.
±15kV ESD-Protected, +5V RS-232 Transceivers
Figure 6a. Human Body ESD Test Model
12
Figure 7a. IEC1000-4-2 ESD Test Model
VOLTAGE
SOURCE
VOLTAGE
SOURCE
HIGH-
HIGH-
______________________________________________________________________________________
DC
DC
CHARGE-CURRENT-
R
CHARGE-CURRENT-
C
LIMIT RESISTOR
LIMIT RESISTOR
50MΩ to 100MΩ
R
C
1MΩ
100pF
150pF
C s
C s
STORAGE
CAPACITOR
STORAGE
CAPACITOR
R
R
RESISTANCE
RESISTANCE
D
DISCHARGE
DISCHARGE
D
1500Ω
330Ω
IEC1000-4-2
DEVICE
UNDER
DEVICE
UNDER
TEST
TEST
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method
connects the probe to the device before the probe is
energized.
The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge
resistance. Its objective is to emulate the stress caused
by contact that occurs with handling and assembly
during manufacturing. Of course, all pins require this
protection during manufacturing, not just RS-232 inputs
and outputs. Therefore, after PC board assembly, the
Machine Model is less relevant to I/O ports.
Figure 6b. Human Body Model Current Waveform
Figure 7b. IEC1000-4-2 ESD Generator Current Waveform
AMPERES
t r = 0.7ns to 1ns
I
P
36.8%
100%
90%
10%
100%
90%
10%
0
I
0
t
RL
30ns
CURRENT WAVEFORM
TIME
60ns
t
DL
I r
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Machine Model
t