XRT59L91ES Exar, XRT59L91ES Datasheet - Page 18

• Manufacturer Part Number: XRT59L91ES
• Description: Peripheral Drivers & Components - PCIs 1 CH E1 AFE
• Manufacturer: Exar

Specifications of XRT59L91ES

• Product Category: Peripheral Drivers & Components - PCIs
• Rohs: yes

3.0
In order to support diagnostic operations, the
XRT59L91 supports the following loopback modes:
Each of these loopback modes will be discussed
below.
3.1
When the XRT59L91 device is configured to operate in
the “Local Loop-back” Mode, the XRT59L91 device will
ignore any signals that are input to the RTIP and RRing
input pins. The “Transmitting Terminal Equipment” will
transmit data (and clock, for “Clocked”
R R ing
LLoop
TR ing
R TIP
TTIP
XRT59L91
Local Loopback
Remote Loopback
The Local Loop-Back Mode
Diagnostic Features
Rev. 1.0.0
Figure 12. Illustration of the “Local Loop-back” within the XRT59L91 Device
E qua lizer
R ece ive
Loop B ack
Local
M U X
P eak D etector/
S licer
P ulse S haping
Local Loop B ack
C ircu it
P ath
18
Mode) into the XRT59L91 device via the TxPOS,
TxNEG and TxCLK input pins. This data will be
processed through the “Transmit Terminal Input Inter-
face” and the “Pulse Shaping” circuit. Finally, this data
will be output to the line via the TTIP and TRing output
pins. Additionally, this data (which is being output via
the TTIP and TRing output pins) will be looped back into
the “Receive Equalizer” block. As a consequence, this
data will also be processed through the entire “Receive
Section” of the XRT59L91 device. After this “post-loop-
back” data has been processed through the “Receive
Section” it will output, to the “Near-End Receiving
Terminal Equipment” via the “RxPOS and RxNEG
output pins.
Figure 12, illustrates the path that the data takes
(within the XRT59L91 device), when the chip is config-
ured to operate in the “Local Loop-back” Mode.
D etector
R xLO S
LO S
R ece ive O utput
Tra nsm it Input
Loop B ack
Interface
R em ote
Interface
M U X
R xP O S
R Loop
R xN E G
TxP O S
TxN E G
TxC lk