MAX14840E Просмотр технического описания (PDF) - Maxim Integrated
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MAX14840E Datasheet PDF : 15 Pages
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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 equip-
ment to meet IEC 61000-4-2, without the need for addi-
tional 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
RC
1MI
CHARGE CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
CS
100pF
RD
1.5kI
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
RC
50MΩ TO 100MΩ
RD
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%
AMPERES
36.8%
10%
0
0 tRL
IR
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
TIME
tDL
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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