XRT91L32ES Exar, XRT91L32ES Datasheet - Page 14

• Manufacturer Part Number: XRT91L32ES
• Description: LIN Transceivers SONET SDH 8 bit TRANCEIVER
• Manufacturer: Exar

Specifications of XRT91L32ES

• Product Category: LIN Transceivers
• Rohs: yes

XRT91L32
STS-12/STM-4 OR STS-3/STM-1 SONET/SDH TRANSCEIVER
The receive section of XRT91L32 include the inputs RXIP/N, followed by the clock and data recovery unit
(CDR) and receive serial-to-parallel converter. The receiver accepts the high speed Non-Return to Zero (NRZ)
serial data at 622.08 Mbps or 155.52 Mbps through the input interfaces RXIP/N. The clock and data recovery
unit recovers the high-speed receive clock from the incoming scrambled NRZ data stream. The recovered
serial data is converted into an 8-bit-wide, 77.76 Mbps or 19.44 Mbps parallel data and presented to the
RXDO[7:0] parallel interface. This parallel interface is designed for Single-Ended LVTTL operation. A divide-
by-8 version of the high-speed recovered clock RXPCLKOP/N, is used to synchronize the transfer of the 8-bit
RXDO[7:0] data with the receive portion of the framer/mapper device. Upon initialization or loss of signal or
loss of lock, the external reference clock signal of 19.44 MHz or 77.76 MHz is used to start-up the clock
recovery phase-locked loop for proper operation. In certain applications, the CDR block on the XRT91L32 can
be disabled and bypassed by enabling the CDRDIS pin to permit the flexibility of using an externally recovered
receive clock thru the XRXCLKIP/N pins.7
The receive serial inputs are applied to RXIP/N. The receive serial inputs can be AC or DC coupled to an
optical module or an electrical interface. A simplified AC coupling block diagram is shown in Figure 3.(Also,
F
refer to application note TAN-9132.)
N
2.0 RECEIVE SECTION
2.1
IGURE
OTE
: 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.
STS-12/STM-4
3. R
STS-3/STM-1
Receive Serial Input
Transceiver
XRT91L32
XRXCLKIN
ECEIVE
XRXCLKIP
or
RXIP
RXIN
S
ERIAL
(optional)
I
NPUT
130 Ohm
I
NTERFACE
Install terminators close to
82 Ohm
RXIP and RXIN pins
B
LOCK
1KOhm
1KOhm
Tie unused differential input pins
12
AC coupled
Internally
to VCC and GND
SFP, Optical Module
xr
Optical Fiber
REV. 1.0.2