ds2155gt-r Maxim Integrated Products, Inc., ds2155gt-r Datasheet - Page 156

• Manufacturer Part Number: ds2155gt-r
• Description: Ds2155 T1/e1/j1 Single-chip Transceiver
• Manufacturer: Maxim Integrated Products, Inc.

24.8 Recommended Circuits
Figure 24-3. Software-Selected Termination, Metallic Protection
Table 24-A. Component List (Software-Selected Termination, Metallic
Protection)
75/100/110/120 Ω
Tw isted Pair/Coax
75/100/110/120 Ω
Tw isted Pair/Coax
Design Notes:
1
2
Choke is optional but should be included when necessary f or common mode noise reduction.
Note 1:
Note 2:
Note 3:
Note 4:
Decoupling capacitors need to be placed near dev ice power pins
T1 and T2
T3 and T4
F1 and F2
S1 and S2
S3 andS4
NAME
T3 and T4 are optional. For more information, contact the Telecom Support Group at
[e-mail].
The layout from the transformers to the network interface is critical. Traces should be at least 25
mils wide and separated from other circuit lines by at least 150 mils. The area under this portion
of the circuit should not contain power planes.
Some T1 (never in E1) applications source or sink power from the network-side center taps of
the Rx/Tx transformers.
A list of transformer part numbers and manufacturers is available by contacting
[e-mail].
F1
F2
1.25A slow blow fuse
25V (max) transient suppressor
77V (max) transient suppressor
Transformer 1:1CT and 1:2CT (3.3V, SMT)
Dual common-mode choke (SMT)
S3
S4
T3
T4
1
1
DESCRIPTION
2:1
1:1
T2
T1
156 of 238
60 Ω
S1
S2
1.0 µF
0.1 µF
60 Ω
TTIP
TRING
RTIP
RRING
Dallas Semiconductor
T1/E1/J1 SCT or LIU
DVDD
DVSS
TVDD
TVSS
RVDD
RVSS
0.01 µF
0.1 µF
0.1 µF
DS2155
2
2
2
VCC
VCC
VCC
0.1 µF
68 µF
2
2