MAX4670 Просмотр технического описания (PDF) - Maxim Integrated
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MAX4670 Datasheet PDF : 20 Pages
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Integrated T1/E1/J1 Short-Haul and
Long-Haul Protection Switch
Table 1. MAX4670 Truth Table
SWITCH
LOW
HIGH
HIGH
—
LOW
HIGH
HIGH
—
LOW
HIGH
HIGH
—
LOW
HIGH
HIGH
INA
X
LOW
HIGH
INB
X
LOW
HIGH
INC
X
LOW
HIGH
IND
X
LOW
HIGH
NC1/NC2
OFF
OFF
ON
NC3/NC4
OFF
OFF
ON
NC5/NC6
OFF
OFF
ON
NC7/NC8
OFF
OFF
ON
NO1/NO2
ON
ON
OFF
NO3/NO4
ON
ON
OFF
NO5/NC6
ON
ON
OFF
NO7/NO8
ON
ON
OFF
Table 2. IEC 61000-4-5 Test Conditions
TEST CONFIGURATION
Differential Surge
(Line to Line)
TEST CONDITIONS
500V peak, 12A min current,
8µs/20µs surge
Common-Mode Surge
(Line to GND)
1000V peak, 24A min current,
8µs/20µs surge
LIU Interface Recommendations
The MAX4670 low 0.7Ω (typ) on-resistance is ade-
quate, even in applications where the LIUs require no
external series transmit resistors (Rt = 0 in Figures 8
and 10). However, in some instances, increase the LIU
output amplitude to compensate for RON if the LIU sup-
ports programmable output amplitude. With LIUs
requiring external transmit resistors, it is recommended
to reduce Rt by the amount of the typical RON with LIUs
requiring external transmit resistors.
For example, if the LIU vendor recommends Rt = 9.1Ω,
the actual value in the application should be:
Rt = Rt – RON = 9.1Ω - 0.7 = 8.4Ω
The receive interface series resistance is small enough
to support LIUs with internal line termination, provided
the external 120Ω parallel resistor combination (Rr) is
connected, as shown in Figures 7 and 9.
While in normal operation, the MAX4670 requires the
input and output signals to be within the V+ and GND
supply rails.
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 Human Body Model. Figure 12
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 interest,
which is then discharged into the test device through a
1.5kΩ resistor.
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment. It does not specifi-
cally refer to ICs. The major difference between tests
done using the Human Body Model and IEC 1000-4-2
is a higher peak current in IEC 1000-4-2, because
series resistance is lower in the IEC 1000-4-2 model.
Hence, the ESD withstands voltage measured to IEC
61000-4-2, and is generally lower than that measured
using the Human Body Model. Figure 13 shows the IEC
61000-4-2 model, and Figure 14 shows the current
waveform for the ±8kV IEC, 61000-4-2 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.
Machine Model
The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resis-
tance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing.
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