Datasheet
MAX3187
±15kV ESD-Protected, EMC-Compliant, 230kbps,
Dual RS-232 Serial Port for Motherboards/Desktops
6 _______________________________________________________________________________________
Human Body Model
Figure 2a shows the Human Body Model, and Figure
2b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
est, which is then discharged into the device through a
1.5kΩ resistor.
IEC 1000-4-2
Since January 1996, all equipment manufactured
and/or sold in the European community has been
required to meet the stringent IEC 1000-4-2 specifica-
tion. The IEC 1000-4-2 standard covers ESD testing
and performance of finished equipment; it does not
specifically refer to integrated circuits. The MAX3187
helps you design equipment that meets Level 4 (the
highest level) of IEC 1000-4-2, without additional ESD-
protection components.
The main difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak
current in IEC 1000-4-2. Because series resistance is
lower in the IEC 1000-4-2 ESD test model (Figure 3a), the
ESD withstand voltage measured to this standard is gen-
erally lower than that measured using the Human Body
Model. Figure 3b shows the current waveform for the
±8kV IEC 1000-4-2 Level 4 ESD Contact-Discharge test.
The Air-Gap test involves approaching the device with a
charge probe. The Contact-Discharge method connects
the probe to the device before the probe is energized.
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
C
s
100pF
R
C
1M
R
D
1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
I
P
100%
90%
36.8%
t
RL
TIME
t
DL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
10%
0
0
AMPERES
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
C
s
150pF
R
C
50M to 100M
R
D
330Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
t
r
= 0.7ns to 1ns
30ns
60ns
t
100%
90%
10%
I
PEAK
I
Figure 3a. IEC 1000-4-2 ESD Test Model
Figure 3b. IEC 1000-4-2 ESD-Generator Current Waveform
Figure 2b. Human Body Model Current Waveform
Figure 2a. Human Body ESD Test Model