xrt5997 Exar Corporation, xrt5997 Datasheet - Page 29

• Manufacturer Part Number: xrt5997
• Description: Xrt5997 -seven Channel E1 Line Interface Unit
• Manufacturer: Exar Corporation

2.3 The “Receive Output Interface” block
The purpose of the “Receive Output Interface” block is
to interface directly with the “Receiving Terminal Equip-
ment”. The “Receive Output Interface” block outputs
the data (which has been recovered from the incoming
line signal) to the “Receive Terminal Equipment” via the
“RxPOS_x and RxNEG_x output pins.
If the “Receive Sections” of the XRT5997 device has
received a “Positive-Polarity” pulse, via the RTIP_x
and RRing_x input pins, then the Receive Output
Interface will output a pulse via the “RxPOS_x” output
pins.
Similarly, if the “Receive Sections” of the XRT5997
device has received a “Negative-Polarity” pulse, via the
RTIP_x and RRing_x input pins, then the Receive
Output Interface will output a pulse via the “RxNEG_x”
output pins.
Rev. 1.0.0
L O S O u tp u t P in
R xIN
Figure 11. The Behavior of the LOS Output Indicator, in response to
Note: F o r E 1 , 1 U I = 4 8 8 n s
the Loss of Signal, and the Restoration of the Signal
0 U I
1 0 U I
A ctu a l O cc u rre n ce
o f L O S C o n d itio n
G .7 7 5 C o m p lia n ce
2 5 5
U I
29
L O S D e cla ra tio n
T im e R a n g e fo r
Note: The “Receive Output Interface” block does not
supply a recovered clock. This device is intended to be
used in those applications, where the “Clock Recovery”
circuit is realized in an ASIC solution.
3.0 Shutting off the Transmitter
Each channel (within the XRT5997 device) permits the
user to shut off the “Transmit Driver” within their
respective “Transmit Section”. This feature can come
in handy for system redundancy design considerations
or during diagnostic testing. The user can activate this
feature by either of the following ways.
Method 1:
Connect the Transmit Data input pins (e.g., TxPOS_x
and TxNEG_x) to a logic “1”; or allow them to float.
(These input pins have an internal “pull-up” resistor).
Method 2:
Connect the “TxClk_x” input pin to a logic “0” (e.g.,
GND) and continue to apply data via the TxPOS_x and
TxNEG_x input pins.
L in e S ig n a l
is R e sto re d
T im e R a n g e fo r
L O S C le a ra n ce
0 U I
1 0 U I
G .7 7 5 C o m p lia n ce
2 5 5 U I
XRT5997