Rainbow Electronics MAX13486E - Manual (Page 13)

+15V 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 driver outputs and receiver inputs of the
MAX13485E/MAX13486E have extra protection against
static electricity. Maxim’s engineers have developed
state-of-the-art structures to protect these pins against
ESD of ±15kV without damage. The ESD structures
withstand high ESD in all states: normal operation, shut-
down, and powered down. After an ESD event, the
MAX13485E/MAX13486E keep working without latchup
or damage.
ESD protection can be tested in various ways. The trans-
mitter outputs and receiver inputs of the MAX13485E/
MAX13486E are characterized for protection to the follow-
ing limits:
• ±15kV using the Human Body Model
• ±15kV using the Air Gap Discharge Method specified
in IEC 61000-4-2 (MAX13485E only)
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 10a shows the Human Body Model, and Figure
10b 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 1.5k
Ω resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. However, it does
not specifically refer to integrated circuits. The
MAX13485E/MAX13486E help equipment designs to
meet IEC 61000-4-2, without the need for additional
ESD-protection components.
The major difference between tests done using the
Human Body Model and IEC 61000-4-2 is higher peak
current in IEC 61000-4-2 because series resistance is
lower in the IEC 61000-4-2 model. Hence, the ESD
MAX13485E/MAX13486E
Half-Duplex RS-485/RS-422 Transceivers in µDFN
______________________________________________________________________________________ 13
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR Cs
100pF
R C
1M Ω
R D
1500 Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 10a. Human Body ESD Test Model
I
P
100%
90%
36.8%
t RL
TIME
t DL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE) Ir
10%
0
0
AMPS
Figure 10b. Human Body Current Waveform
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR Cs
150pF
R C
50M Ω TO 100MΩ
R D
330 Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 10c. ICE 61000-4-2 ESD Test Model
t r = 0.7ns TO 1ns
30ns
60ns
t
100%
90%
10%
I PEAK
I
Figure 10d. IEC 61000-4-2 ESD Generator Current Waveform