Datasheet

DS26504 T1/E1/J1/64KCC BITS Element
80 of 129
13. LINE INTERFACE UNIT (LIU)
The LIU in the DS26504 contains three sections: the receiver, which handles clock and data recovery; the
transmitter, which generates waveshapes and drives the network line; and the jitter attenuator. These three
sections are controlled by the line interface control registers (LIC1–LIC4), which are described below.
The DS26504 can switch among T1, J1, E1, and 6312kHz without changing any external circuits. A
different transformer is used for 64KCC networks. For a list of recommended transformer part numbers,
go to www.maxim-ic.com/support. Figure 13-1 shows a network connection using minimal components.
In this configuration the DS26504, using a fixed 120Ω external termination, can connect to T1, J1, E1,
64KCC, or 6312kHz. The receiver can adjust the 120Ω termination to 100Ω, 110Ω, or 75Ω. The
transmitter can adjust its output impedance to provide high return loss characteristics for 75Ω, 100Ω,
110Ω, and 120Ω lines. Other components may be added to this configuration to meet safety and network
protection requirements. This is covered in the Recommended Circuits section (Section 13.8).
Figure 13-1. Basic Network Connection
TTIP
TRING
RTIP
RRING
DS26504
TRANSMIT
LINE
RECEIVE
LINE
10
μ
F
60Ω 60
Ω
0.01
μ
F
BACKPLANE
CONNECTIONS
1:1
2:1