XRT75L03 datasheet(21/92 Pages) EXAR

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XRT75L03

THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR

REV. 1.0.4

CLOCK INTERFACE

PIN #SIGNAL NAME

TYPE

DESCRIPTION

107

E3Clk/ CLK_EN

E3 Clock Input (34.368 MHz ± 20 ppm):

If all the 3 channels or any one of the channels is configured in E3 mode, a ref-

erence clock 34.368 MHz ± 20 ppm is input to this pin..

Clock Output Enable:

If the Single Frequency Mode is selected, tie this pin “High” to enable the clock

output through the CLK_OUT pin (pin 108).

108

DS3Clk/ CLK_OUT

I/O

DS3 Clock Input (44.736 MHz ± 20 ppm):

If all the 3 channels or any one of the channels is configured in DS3 mode, a ref-

erence clock 44.736 MHz ± 20 ppm is input to this pin.

Clock Output:

When the Single Frequency Mode is enabled, this pin is configured as the clock

output from Channel 1.This clock frequency is determined by the Channel 1 set-

ting..

NOTE: This low jitter output clock can be used as the input clock source for the

framer device. thus eliminating the need for a separate clock source for

the framer.

109

STS-1Clk/ 12M

STS-1 Clock Input (51.84 MHz ± 20 ppm):

If all the 3 channels or any one of the channels is configured in STS-1 mode, a

reference clock 51.84 MHz ± 20 ppm is input to this pin.

Single Frequency Mode Clock Input:

In Single Frequency Mode, a reference clock of 12.288 MHz ± 20 ppm is con-

nected to this pin and the internal clock synthesizer generates the appropriate

clock frequencies based on the configuration of the rates (E3 or DS3 or STS-1).

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