XRT75L03 Datasheet, PDF (18/92 Pages) Exar Corporation – THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR

XRT75L03
REV. 1.0.4
THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
SYSTEM-SIDE RECEIVE OUTPUT AND RECEIVE CONTROL PINS
PIN #
SIGNAL NAME
TYPE
DESCRIPTION
107 E3Clk/ CLK_EN
I
E3 Reference Clock Input/SFM Clock Output Enable:
The function of this chip depends upon whether or not the XRT75L03 has been
configured to operate in the Single-Frequency Mode.
If NOT operating in the Single-Frequency Mode
If the XRT75L03 has NOT been configured to operate in the SFM (Single Fre-
quency) Mode, and if at least one channel is to be operated in the E3 Mode,
then a 34.368MHz clock signal must be applied to this input pin.
If the user does not intend to operate the device in the SFM Mode nor operate
any of the channels in the E3 Mode tie this input signal to GND.
If operating in the Single-Frequency Mode
If the XRT75L03 is operated in the SFM Mode and is to output a clock signal
that is synthesized from the SFM Clock Synthesizer PLL so that the user’s sys-
tem can use this clock signal as a timing source, pull this input pin to a logic
"High".
If the user pull this input pin "High", then the XRT75L03 will output the line rate
clock signal that has been synthesized for Channel 1, via pin 108 (DS3CLK/
CLK_OUT).
For example, if Channel 1 is configured to operate in the STS-1 Mode and this
input pin is pulled "High", then the XRT75L03 will output a 51.84MHz clock sig-
nal via the CLK_OUT pin.
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