±15kV ESD-Protected, Quad,
Low-Power RS-232 Line Receiver
MAX1489E
R
C
1M
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
R
D
1500Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
I
P
100%
90%
AMPERES
Cs
100pF
STORAGE
CAPACITOR
36.8%
10%
0
0
t
RL
TIME
t
DL
CURRENT WAVEFORM
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Figure 2a. Human Body ESD Test Model
Figure 2b. Human Body Model Current Waveform
_______________Detailed Description
±15kV ESD Protection
As with all Maxim devices, ESD protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The MAX1489E receiver inputs have extra
protection against static electricity found in normal
operation. Maxim’s engineers developed state-of-the-
art structures to protect these pins against ESD of
±15kV without damage. After an ESD event, the
MAX1489E keeps working without latchup.
ESD protection can be tested in various ways; the
receiver inputs are characterized for protection to the
following:
1) ±15kV using the Human Body Model
2) ±8kV using the Contact Discharge method speci-
fied in IEC1000-4-2 (formerly IEC801-2)
3) ±15kV using the Air-Gap Discharge method speci-
fied in IEC1000-4-2 (formerly IEC801-2).
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 test device
through a 1.5kΩ resistor.
IEC1000-4-2
The IEC100-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifically
refer to integrated circuits. The MAX1489E helps you
design equipment that meets Level 4 (the highest level)
of IEC1000-4-2, without additional ESD protection com-
ponents.
The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak cur-
rent in IEC1000-4-2. Because series resistance is lower
in the IEC1000-4-2 ESD test model (Figure 3a), the ESD
withstand voltage measured to this standard is generally
lower than that measured using the Human Body Model.
Figure 3b shows the current waveform for the ±8kV
IEC1000-4-2 Level 4 ESD Contact Discharge 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.
ESD Test Conditions
Contact Maxim for a reliability report that documents
test setup, methodology, and results.
4
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