Maxim DS21Q55 specifications Line Interface Unit LIU, Basic Network Connections Figure

Models: DS21Q55

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DS21Q55

23. LINE INTERFACE UNIT (LIU)

The LIU in the DS21Q55 contains three sections: the receiver, which handles clock and data recovery; the transmitter, whic h wave-shapes 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 LIU has its own T1/E1 mode select bit and can operate independently of the framer function.

The DS21Q55 can switch between T1 or E1 networks without changing any external components on either the transmit or receive side. Figure 25-1 shows a network connection using minimal components. In this configuration the device can connect to T1, J1, or E1 (75O or 120O) without any component change. The receiver can adjust the 120O termination to 100O or 75O. The transmitter can adjust its output impedance to provide high return loss characteristics for 120O, 100O, and 75O lines. Other components may be added to this configuration in order to meet safety and network protection requirements. This is covered in Recommended Circuits.

BASIC NETWORK CONNECTIONS Figure 25-1

 

TTIP

TRANSMIT

1µF

BACKPLANE CONNECTIONS

LINE

 

TRING

2:1

DS21Q55

RTIP

RECEIVE

LINE

RRING

1:1

60 60

0.01µF

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Please contact telecom.support@dalsemi.com or search http://www.maxim-ic.com for updated

information.

Page 149
Image 149
Maxim DS21Q55 specifications Line Interface Unit LIU, Basic Network Connections Figure