Datasheet

DS26518 8-Port T1/E1/J1 Transceiver

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Figure 9-21. Network Connection—Longitudinal Protection

DS26518

TTIPn

TRINGn

RTIPn

RRINGn

2:1

1:1

TIP

RING

TIP

RING

560 pF

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,

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 1:2CT (3.3V, SMT) PE-68678 Pulse Engineering 2, 3, 5

T3 and T4 Dual Common-Mode Choke (SMT) PE-65857 Pulse Engineering 5

Termination Resistor (120Ω, 110Ω, 100Ω, or

75Ω)

— — —

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 S3/S4 pair and the S5/S6 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 technical support at

www.maxim-ic.com/support or in Application Note 324, which is available at www.maxim-ic.com/AN324.

Note 6:

The 1μF capacitor in series with TTIPn is only necessary for G.703 clock sync applications.

Note 7: The 560pF on TTIPn/TRINGn must be tuned to your application.