XRT91L82
2.488/2.666 Gbps OC-48/STM-16 SONET/SDH 16 Bit Transceiver
Exar Corporation offers an extensive portfolio of
products for networking and transmission
applications
T
he XRT91L82 is a fully integrated SONET/SDH transceiver
for SONET OC-48 and SDH STM-16 allowing the use of
Forward Error Correction (FEC) capability. The transceiver
includes an on-chip Clock Multiplier Unit (CMU), which uses a
high frequency Phase-Locked Loop (PLL) to generate the
high-speed transmit serial clock from slower external clock
references. It also provides Clock and Data Recovery (CDR)
functions by synchronizing its on-chip Voltage Controlled
Oscillator (VCO) to the incoming serial data stream. The chip
provides serial-to-parallel and parallel-to-serial converters and 16bit optional Low Voltage Differential Signaling (LVDS) or Low
Voltage Positive Emitter Coupled Logic (LVPECL) system
interfaces in both receive and transmit directions. The transmit
section includes an Elastic Buffer First In First Out (FIFO) to
absorb any phase differences between the transmitter input clock
and the internally generated transmitter reference clock.
Major Features
• 2.488 / 2.666 GBps Transceiver
• Single-chip fully integrated
solution containing parallel-toserial converter, clock multiplier
unit (CMU), serial-to-parallel
converter and clock data recovery
(CDR) functions
In the event of an overflow, an internal FIFO control circuit outputs
an OVERFLOW indication. The FIFO under the control of the
FIFO RESET pin can automatically recover from an overflow
condition. The operation of the device can be monitored by
checking the status of the Lock Detect and Loss of Signal output
signals. An on-chip phase/frequency detector and charge-pump
offers the ability to form a de-jittering PLL with an external VCXO
that can be used in loop timing mode to clean up the recovered
clock in the receive section.
• Host mode serial microprocessor
interface simplifies monitor and
control
The low-jitter, parallel 16-bit optional LVDS or LVPECL interface
guarantees compliance with the bit-error rate requirements of the
Telecordia and ITU-T standards.
• Selectable full duplex operation
between standard rate of 2.488
Gbps or Forward Error Correction
rate of 2.666 Gbps
• Separate reference and VCXO
input ports support multiple
de-jittering modes
• On-chip phase detector and charge
pump for external VCXO based
de-jittering PLL
• Targeted for SONET OC-48/SDH
STM-16 Applications
XRT91L82
2.488/2.666 Gbps OC-48/STM-16
SONET/SDH 16 Bit Transceiver
XR91L82 Block Diagram
OC- 48 TRANSCEIVER
FIFO _ RST
WP
FIFO _ AUTORST
FI F O
TxDI 0P/N
TxDI 1P/N
TxDI15P/N
PISO
( Parallel Input
Serial Output )
TXOP /N
Re-Timer
RP
TxCLKIP/N
TXPCLKOP /N
TXCLKO16P/N
CMU
RLOOPP
TRITXCLKO16
RLOOPS
DLOOP
RxDO 0P/ N
SIPO
( Serial Input
Parallel Output )
RxDO 1 P/N
CDR
RXI 0 P/N
RxDO 15 P/N
RxCLKP /N
RXCLK 16 P/N
TRIRXD
DISRD
TDO
TDI
TCK
TMS
Serial
Microprocessor
JTAG
PFD
& Charge Pump
Hardware
Control
Applications
Features
• 16-bit optional LVDS or LVPECL data paths at
155/167 MHz
• Internal FIFO decouples transmit input and output clocks
R EF CL KP/N
V CXO_ IN P/N
REF F R EQS EL
V CX O_SEL
VC XO_L OC KEN
VC XO_L OC K
C POU T
L OCK DE T_ C DR
LOC KD ET _C MU
L OSD ET
LOSE XT
POL AR IT Y
TE ST
OVE RF L OW
LOOP BW
L PT M_ NO_ JA
RL OOPP
DL OOP
LP TI ME_ JA
RL OOPS
SD I
SD O
H ost/H w
CS
SC LK
IN T
Re se t
TRST
• SONET/SDH-based Transmission Systems
• Add/Drop Multiplexers
• Tx CMU and Rx CDR lock detect
• Cross Connect Equipment
• Provides Local, Remote and Split Loop-Back
modes as well as Loop Timing mode
• ATM and Multi-Service Switches, Routers
and Switch/Routers
• Diagnostics features include various lock detect
functions
• DSLAMS
• Meets Telcordia, ANSI and ITU-T jitter requirements
• SONET/SDH Test Equipment
• Operates at 1.8V with 3.3V I/O
• DWDM Termination Equipment
• 600mW Typical Power Dissipation
• Package: 15 x 15 mm 196-pin STBGA
• IEEE 1149.1 Compatable JTAG port
• No external passive components required
• No external heatsink or airflow required
• ESD greater than 2kV on all pins
• Reference frequency of 155.52/77.76 MHz
(or equivalent rate for FEC operation)
• Loss of Signal Detect on the High Speed interface
FLY0905_XRT91L82
©2005 Exar Corporation
Ordering Information
Product No.
XRT91L82IB
Package
Operating
Temp. Range
196 STBGA
-40ºC to +85ºC
Exar Corporation • 48720 Kato Road • Fremont, CA 94538 • 510.668.7000 • fax 510.668.7001 • www.exar.com