DS2149 MAXIM [Maxim Integrated Products], DS2149 Datasheet - Page 24

• Manufacturer Part Number: DS2149
• Description: 5V T1/J1 Line Interface Unit
• Manufacturer: MAXIM [Maxim Integrated Products]

11. NETWORK INTERFACE
Transformer specifications are listed in
resistance necessary for the basic interface and is associated with different transformer turns ratios.
Smaller turns ratios result in lower power-supply requirements. However, series resistance provides
added protection from potentially damaging voltages that can occur during lightning strikes. A basic
network interface is illustrated in
refer to Application Note 324: T1/E1 Network Interface Design.
Table 11-A. Specifications for Receive Transformer
Turns Ratio (all applications)
Primary Inductance
Leakage Inductance
Interwinding Capacitance
Receive Transformer DC Resistance
Table 11-B. Specifications for Transmit Transformer
Turns Ratio, 5V
Primary Inductance
Leakage Inductance
Interwinding Capacitance
Transmit Transformer DC Resistance
Table 11-C. Transformer Turns Ratio vs. Series Resistance
XFMR2
(CR4.1)
0
0
1
1
Primary (Device Side)
Secondary
Primary (Device Side)
Secondary
SPECIFICATION
SPECIFICATION
XFMR1
(CR4.0)
0
1
0
1
OPERATING
VOLTAGE
(V)
5.0
5.0
5.0
5.0
Figure
1:2 ±2%
600mH minimum
1.0mH maximum
40pF maximum
1.0Ω maximum
2.0Ω maximum
600mH minimum
1.0mH maximum
40pF maximum
1.2Ω maximum
1.2Ω maximum
1:1 ±2%
Table 11-A
RECOMMENDED VALUE
RECOMMENDED VALUE
11-1. For a complete discussion of network interface design,
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APPLICATION
Long/Short
Long/Short
Long/Short
Long/Short
and
D4
D4
D4
D4
Table
11-B.
Table 11-C
1:1.15
1:1.15
1:1.6
1:1.6
1:2
1:2
1:2
1:2
1:2
1:2
1:2
1:2
N
illustrates the series
Rt (Ω)
9.1
4:3
4.3
9.1
0
0
0
0
0
0
0
0