MAX14840E_15 Datasheet, PDF (14/16 Pages) Maxim Integrated Products – 40Mbps, +3.3V, RS-485 Half-Duplex Transceivers

MAX14840E/MAX14841E 40Mbps, +3.3V, RS-485 Half-Duplex Transceivers
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 11 shows the HBM, and Figure 12 shows the current
waveform it generates when discharged into a low-
impedance state. This model consists of a 100pF capacitor
charged to the ESD voltage of interest, which is then
discharged into the test device through a 1.5kI 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 MAX14840E/
MAX14841E family of devices helps you design equipment
to meet IEC 61000-4-2, without the need for additional
ESD protection components.
The major difference between tests done using the HBM
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 withstand voltage measured to
IEC 61000-4-2 is generally lower than that measured
using the HBM.
Figure 13 shows the IEC 61000-4-2 model, and Figure
14 shows the current waveform for IEC 61000-4-2 ESD
Contact Discharge test.
Applications Information
High-Speed Operation
The MAX14840E and MAX14841E are high-performance
RS-485 transceivers supporting data rates up to 40Mbps.
Driver Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus contention.
Current limit on the output stage provides immediate
RC
1MI
CHARGE CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
CS
100pF
RD
1.5kI
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
R_C
50MΩ TO 100MΩ
R_D
330Ω
CHARGE CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
HIGH-
VOLTAGE
DC
SOURCE
Cs
150pF
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
Figure 11. Human Body ESD Test Model
IP 100%
90%
IR
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPERES
36.8%
10%
0
0 _tRL
TIME
t_DL
CURRENT WAVEFORM
Figure 12. Human Body current Waveform
Figure 13. IEC 61000-4-2 ESD Test Model
I
100%
90%
10%
tR = 0.7ns TO 1ns
30ns
t
60ns
Figure 14. IEC 61000-4-2 ESD Generator Current Waveform
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