CA16-Type 2.5 Gbits/s DWDM Transponder with
16-Channel 155 Mbits/s Multiplexer/Demultiplexer
Advance Data Sheet
March 2001
Pin Descriptions
(continued)
Table 2. CA16-Type Transponder Input Pin Descriptions
Pin Name
TxD[0:15]P
TxD[0:15]N
Pin Description
16-Bit Differential LVPECL Parallel Input Data Bus.
TxD15P/N is the most significant bit of the
input word and is the first bit serialized. TxD00P/N is the least significant bit of the input word and
is the last bit serialized. TxD[0:15]P/N is sampled on the rising edge of PIC
LK
.
PIC
LK
P
Differential LVPECL Parallel Input Clock.
A 155 MHz nominally 50% duty cycle input clock to
PIC
LK
N
which TxD[0:15]P/N is aligned. The rising edge of PIC
LK
transfers the data on the 16 TxD inputs
into the holding register of the parallel-to-serial converter.
TxR
EF
C
LK
P
Differential LVPECL Low Jitter 155.520 MHz Input Reference Clock.
This input is used as the
TxR
EF
C
LK
N reference for the internal clock frequency synthesizer, which generates the 2.5 GHz bit rate clock
used to shift data out of the parallel-to-serial converter and also for the byte-rate clock, which
transfers the 16-bit parallel input data from the input holding register into the parallel-to-serial shift
register. Input is internally terminated and biased. See discussion on timing interface, page 18.
TxDIS
Transmitter Disable Input.
A logic high on this input pin shuts off the transmitter’s laser so that
there is no optical output.
WS
Wavelength Select.
When this input is a logic 0 or left floating, the output wavelength will be the
nominal wavelength (at 25 °C); when it is a logic 1, the wavelength will increase by approximately
0.8 nm (100 GHz frequency decrease).
DLOOP
Diagnostic Loopback Enable (LVTTL).
When the D
LOOP
input is low, the 2.5 Gbits/s serial data
stream from the parallel-to-serial converter is looped back internally to the serial-to-parallel con-
verter along with an internally generated bit synchronous serial clock. The received serial data
path from the optical receiver is disabled.
LLOOP
Line Loopback Enable (LVTTL).
When L
LOOP
is low, the 2.5 Gbits/s serial data and recovered
clock from the optical receiver are looped directly back to the optical transmitter. The multiplexed
serial data from the parallel-to-serial converter is ignored.
PHINIT
Phase Initialization (Single-Ended LVPECL).
This input is used to align the internal elastic store
(FIFO). A rising edge on PHINIT will realign the internal timing (see FIFO discussion, pages 12
and 18).
FRAMEN
*
Frame Enable Input (LVTTL).
Enables the frame detection circuitry to detect A1, A2 byte align-
ment and to lock to a word boundary. The CA16 transponder will continually perform frame acqui-
sition as long as FRAMEN is held high. When this input is low, the frame-detection circuitry is
disabled. Frame-detection process is initiated by rising edge of out-of-frame pulse.
*
OOF
Out of Frame (LVTTL).
This input indicator is typically generated by external SONET/SDH over-
head monitor circuitry in response to a state in which the frame boundaries of the received
SONET/SDH signal are unknown, i.e., after system reset or loss of synchronization. The rising
edge of the OOF input initiates the frame detection function if FRAMEN is high. The FP output
goes high when the frame boundary is detected in the incoming serial data stream from the opti-
cal receiver.
RESET
Master Reset (LVTTL).
Reset input for the multiplexer and demultiplexer. A logic low on this input
clears all buffers and registers. During RESET, POC
LK
and PC
LK
do not toggle.
* Future versions of the cooled transponder will not support the frame-detect function.
10
Agere Systems Inc.
AGERE [ AGERE SYSTEMS ]
