xrt91l31 Exar Corporation, xrt91l31 Datasheet - Page 10

• Manufacturer Part Number: xrt91l31
• Description: Sts-12/stm-4 Or Sts-3/stm-1 Sonet/sdh Transceiver
• Manufacturer: Exar Corporation

TRANSMITTER SECTION
XRT91L31
STS-12/STM-4 OR STS-3/STM-1 SONET/SDH TRANSCEIVER
TTLREFCLK
REFCLKP
REFCLKN
N
AME
LVPECL Diff
LVCMOS
LVTTL,
L
EVEL
T
YPE
I
I
P
16
17
36
IN
Reference Clock Input (77.76 MHz or 19.44 MHz)
This differential clock input reference is used for the transmit
clock multiplier unit (CMU) and clock data recovery (CDR) to
provide the necessary high speed clock reference for this
device. It will accept either a 77.76 MHz or a 19.44 MHz Differ-
ential LVPECL clock source. Pin CMUFREQSEL determines
the value used as the reference. See Pin CMUFREQSEL for
more details. REFCLKP/N inputs are internally biased to 1.65V.
N
Auxillary Reference Clock Input (77.76 MHz or 19.44 MHz)
This LVTTL clock input reference is used for the transmit clock
multiplier unit (CMU) and clock data recovery (CDR) to provide
the necessary high speed clock reference for this device. It will
accept either a 77.76 MHz or a 19.44 MHz LVTTL clock source.
Pin CMUFREQSEL determines the value used as the refer-
ence. See Pin CMUFREQSEL for more details.
N
OTE
OTE
10
: In the event that TTLREFCLK LVTTL input is used
: In the event that REFCLKP/N differential inputs is used
instead of these differential inputs for clock reference,
the REFCLKP should be tied to ground.
instead of this LVTTL input for clock reference, the
TTLREFCLK should be tied to ground.
D
ESCRIPTION
REV. 1.0.0