XRT91L34
8
QUAD CHANNEL MULTIRATE STS-12/3/1 AND STM-4/1/0 SONET/SDH CDR
REV. 1.0.1
DLOSDIS
/SDI
LVTTL,
LVCMOS
I 39 DLOS (Digital Loss of Signal) Disable
Hardware Mode Disables internal DLOS monitoring and auto-
matic muting of RXDO[3:0]P/N recovered data output pins upon
DLOS detection. DLOS is declared when the incoming data
stream has no transition for more than 2.5µs. DLOS is cleared
when transitions are detected within a 128µs interval sliding
window.
"Low" = Monitor & Mute recovered data upon DLOS declaration
"High" = Disable internal DLOS monitoring
This pin is provided with an internal pull-down.
Host Mode This pin is functions as the microprocessor Serial
Data Input.
POL0
POL1
POL2
POL3
LVTTL,
LVCMOS
I 126
124
36
34
Polarity for SDEXT Input
Controls the Signal Detect polarity convention of SDEXT.
"Low" = SDEXT is active "Low."
"High" = SDEXT is active "High."
N
OTE
: These pins have no function in Host Mode.
These pins are provided with internal pull-down.
SDEXT0
SDEXT1
SDEXT2
SDEXT3
LVTTL,
LVCMOS,
I 127
125
35
33
Signal Detect Input from Optical Module
When inactive, it will immediately declare a Loss of Signal
(LOS) condition and assert LOS register bit and mute the activ-
ity of the RXDO[3:0]P/N serial data output on the respective
channel.
"Active" = Normal Operation
"Inactive" = LOS Condition (SDEXT detects signal absence)
These pins are provided with internal pull-down.
REFCLKP
REFCLKN
LVDS,
Diff LVPECL
I 117
118
Reference Clock Input (77.76 MHz or 19.44 MHz)
This differential reference clock input will accept either a 77.76
MHz or a 19.44 MHz LVDS/Differential LVPECL clock source.
Pin CDRREFSEL determines the value used as the reference.
See Pin CDRREFSEL for more details. REFCLKP/N inputs are
internally biased to 1.2V via 15kΩ resistance. These pins are
equipped with a 100Ω line-to-line internal termination.
N
OTE
: In the event that TTLREFCLK LVTTL/LVCMOS input is
used instead of these differential inputs for clock
reference, the REFCLKP should be left unconnected
and REFCLKN should be tied to GND.
TTLREFCLK LVTTL,
LVCMOS
I 120 TTL Reference Clock Input (77.76 MHz or 19.44 MHz)
This optional single-ended clock input reference can be used
instead of the differential REFCLKP/N input. It will accept
either a 77.76 MHz or a 19.44 MHz LVTTL clock source. Pin
CDRREFSEL determines the value used as the reference. See
Pin CDRREFSEL for more details.
N
OTE
: In the event that REFCLKP/N differential inputs are
used instead of this LVTTL/LVCMOS input for clock
reference, the TTLREFCLK should be tied to ground.
This pin is provided with an internal pull-down.
N
AME
L
EVEL
T
YPE
P
IN
D
ESCRIPTION
