xrt91l31 Exar Corporation, xrt91l31 Datasheet - Page 30

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

XRT91L31
STS-12/STM-4 OR STS-3/STM-1 SONET/SDH TRANSCEIVER
The 622.08 Mbps STS-12/STM-4 or 155.52 Mbps STS-3/STM-1 transmit serial output is avaliable on TXOP/N
pins. The transmit serial output can be AC or DC coupled to an optical module or electrical interface. A
simplified block diagram is shown in
F
N
F
3.8
IGURE
OTE
IGURE
: Some optical modules integrate AC coupling capacitors within the module. AC or DC coupling is largely specific to
system design and optical module of choice.
17. T
16. L
Transmit Serial Output Control
RANSMIT
OOP
STS-12/STM-4
T
STS-3/STM-1
Transceiver
XRT91L31
IMING
RXDO[7:0]
RXPCLKO
TTLREFCLK
LOOPTIME
TXDI[7:0]
REFCLKN
REFCLKP
TXPCLK_IO
PIO_CTRL
CDRDIS
S
or
ERIAL
TXOP
TXON
M
~ ~
ODE
ENB
O
Div by 8
UTPUT
U
ENB
8
SING
0
1
8
Figure
I
I
NTERFACE BLOCK
NTERNAL
Div by
SIPO
155.52MHz
8
622.08/
CMU
PISO
17.
DATA
CLK
187 Ohm Pull Down Resistors
MUX
CDR
XRT91L31
30
OR AN
DATA
CLK
Optical Module
AC-Coupled SFP
E
to Retimer
Clk
Data
XTERNAL
CDR
Retimer
R
ECOVERED
~ ~
XRXCLKIP
XRXCLKIN
RXIP
RXIN
TXOP
TXON
Optical Fiber
C
LOCK
REV. 1.0.0