Datasheet

DS26521 Single T1/E1/J1 Transceiver
68 of 258
Figure 8-17. Basic Balanced Network Connections
Dallas
Single Chip Transceiver
or
Line Interface Unit
DVDD
DVSS
TVSS
TVDD
RVSS
RVDD
0.01 uF 0.1 uF
68 uF
0.1 uF
0.1 uF
3.3 V
3.3 V
TTIP
TRING
RTIP
RRING
S1
S2
S3
S4
S5
S6
S7
S8
T1
T2
T3
T4
2:1
1:1
F1
F2
F3
F4
TX
TIP
TX
RING
RX
TIP
RX
RING
560 pF
60 60
0.1 uF
NAME DESCRIPTION PART MANUFACTURER NOTES
1.25A Slow Blow Fuse SMP 1.25 Bel Fuse 5
F1 to F4
1.25A Slow Blow Fuse F1250T Teccor Electronics 5
S1, S2 25V (max) Transient Suppressor P0080SA MC Teccor Electronics 1, 5
S3, S4, S5, S6 180V (max) Transient Suppressor P1800SC MC Teccor Electronics 1, 4, 5
S7, S8 40V (max) Transient Suppressor P0300SC MC Teccor Electronics 1, 5
T1 and T2 Transformer 1:1CT and 1:136CT (5.0V, SMT) T1136 Pulse Engineering 2, 3, 5
T1 and T2 Transformer 1:1CT and 1:2CT (3.3V, SMT) PE-68678 Pulse Engineering 2, 3, 5
T3 and T4 Dual Common-Mode Choke (SMT) PE-65857 Pulse Engineering 5
Note 1: Changing S7 and S8 to P1800SC devices provides symmetrical voltage suppresion between tip, ring, and ground.
Note 2: 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 3: Some T1 (never in E1) applications source or sink power from the network-side center taps of the Rx/Tx transformers.
Note 4: 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.
Note 5: Alternative component recommendations and line interface circuits can be found by contacting
[e-mail] or in Application Note 324, which is available at www.maxim-ic.com/AN324.