Datasheet

DS26503 T1/E1/J1 BITS Element
91 of 122
Figure 13-5. Software-Selected Termination, Longitudinal Protection
Table 13-2. Component List (Software-Selected Termination, Longitudinal
Protection)
NAME DESCRIPTION
F1 to F4 1.25A slow blow fuse
S1 and S2 25V (max) transient suppressor (Note 1)
S3, S4, S5, S6 180V (max) transient suppressor (Note 1)
S7 and S8 40V (max) transient suppressor
Transformer 1:1CT and 1:136CT (5.0V, SMT) (Note 2)
T1 and T2
Transformer 1:1CT and 1:2CT (3.3V, SMT) (Note 2)
T3 and T4 Dual common-mode choke (SMT)
Note 1:
T3 and T4 are optional. For more information, contact the Telecom Support Group at
www.maxim-ic.com/support
.
Note 2:
A list of alternate transformer part numbers and manufacturers is available at
www.maxim-ic.com/support
.
Note 3:
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.
Note 4:
Some T1 (never in E1) applications source or sink power from the network-side center taps of
the Rx/Tx transformers.
Note 5:
The ground trace connected to the S2/S3 pair and the S4/S5 pair should be at least 50 mils wide
to conduct the extra current from a longitudinal power-cross event.