XRT73L00A Datasheet, PDF (7/53 Pages) Exar Corporation – E3/DS3/STS-1 LINE INTERFACE UNIT

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PIN DESCRIPTION
PIN #
SYMBOL
10
RxAVDD
11
REGRESET/
(RCLK2INV)
12
REQDIS
13
LOSTHR
14
LLB
XRT73L00A
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. 2.0.1
TYPE
****
I
I
I
I
DESCRIPTION
Receive Analog Power Supply
Register Reset Input pin (Invert RCLK2 Output - Select):
The function of this pin depends upon whether the XRT73L00A is operating in
the HOST Mode or in the Hardware Mode.
HOST Mode - Register Reset Input pin:
Setting this input pin “Low” causes the XRT73L00A to reset the contents of the
Command Registers to their default settings and operating configuration. This
pin is internally pulled “High”.
Hardware Mode - Invert RCLK2 Output Select:
Setting this input pin “Low” configures the Receive Section of the XRT73L00A to
output the recovered data via the RPOS and RNEG output pins on the rising
edge of the RCLK2 output signal.
Setting this input pin “High” configures the Receive Section to output the recov-
ered data on the falling edge of the RCLK2 output signal.
Receive Equalization Disable Input:
Setting this input pin “High” disables the Internal Receive Equalizer in the
XRT73L00A. Setting this pin “Low” enables the Internal Receive Equalizer. The
guidelines for enabling and disabling the Receive Equalizer are described in
Section 3.2.
NOTES:
1. This input pin is ignored if the XRT73L00A is operating in the HOST
Mode.
2. Tie this pin to GND if the XRT73L00A is going to be operating in the
HOST Mode.
Loss of Signal Threshold Control:
This input pin is used to select the LOS (Loss of Signal) Declaration and Clear-
ance thresholds for the Analog LOS Detector circuit. Two settings are provided
by forcing this signal to either GND or VDD.
NOTE: This pin is only applicable during DS3 or STS-1 operations.
Local Loop-Back Select:
This input pin along with RLB dictates which Loop-Back mode the XRT73L00A is
operating in.
A “High” on this pin with RLB being set to “Low” configures the XRT73L00A to
operate in the Analog Local Loop-Back Mode.
A “High” on this pin with RLB also being set to “High” configures the XRT73L00A
to operate in the Digital Local Loop-Back Mode.
NOTES:
1. This input pin is ignored if the XRT73L00A is operating in the HOST
Mode.
2. Tie this pin to GND if the XRT73L00A is going to be operating in the
HOST Mode.
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