SLK2501 Datasheet, PDF (7/20 Pages) Texas Instruments – OC-48/24/12/3 SONET/SDH MULTIRATE TRANSCEIVER

SLK2501
OCĆ48/24/12/3 SONET/SDH MULTIRATE TRANSCEIVER
SLLS502A – OCTOBER 2001 – REVISED NOVEMBER 2001
detailed description
The SLK2501 is designed to support OC-48/24/12/3. The operating data speed can be configured through
RSEL0 and RSEL1 pins as indicated in Table 1.
Table 1. Data Rate Select
SERIAL DATA RATE
OC-48:2.488 Gb/s
OC-24:1.244 Gb/s
OC-12:622 Mb/s
OC-3:155.52 Mb/s
RSEL0
0
1
0
1
RSEL1
0
0
1
1
PARALLEL LVDS DATA RATE
622.08 Mbps
311.04 Mbps
155.52 Mbps
38.88 Mbps
TXCLK/RXCLK
622.08 MHz
311.04 MHz
155.52 MHz
38.88 MHz
The user can also enable the autorate detection circuitry through the AUTO_DETECT pin. The device
automatically detects the OC-N of the data line rate and generates two bits of output to indicate the data rate
to other devices in the system. When using AUTO_DETECT, RSEL0 and RSEL1 need to be set to 00 or be
unconnected.
Table 2. Data Rate Reporting Under Autorate Detection Mode
SERIAL DATA RATE
OC-48:2.488 Gb/s
OC-24:1.244 Gb/s
OC-12:622 Mb/s
OC-3:155.52 Mb/s
RATEOUT0
0
1
0
1
RATEOUT1
0
0
1
1
PARALLEL LVDS DATA RATE
622.08 Mbps
311.04 Mbps
155.52 Mbps
38.88 Mbps
TXCLK/RXCLK
622.08 MHz
311.04 MHz
155.52 MHz
38.88 MHz
The SLK2501 has four operational modes controlled by two configuration pins. These operational modes are
listed in Table 3. When the device is put in a certain mode, unused circuit blocks are powered down to conserve
the system power.
While the transceiver mode, transmit only mode, and receive only mode are straightforward, the repeater mode
of operation is shown in Figure 5. The receive serial data is recovered by the extracted clock, and it is then sent
back out on the transmit serial outputs. The data eye is open both vertically and horizontally in this process. In
the repeater mode, user can select to turn on the RX demux function through RX_MONITOR pin and allow the
parallel data to be presented. This feature enables the repeater device not only to repeat but also to listen in.
Table 3. Operational Modes
MODE
1
2
3
4
CONFIG0
0
0
1
1
CONFIG1
0
1
0
1
DESCRIPTION
Full duplex transceiver mode
Transmit only mode
Receive only mode
Repeater mode
high-speed electrical interface
The high-speed serial I/O uses a PECL compatible interface. The line could be directly coupled or ac-coupled.
Refer to Figures 10 and 11 for configuration details. As shown in the figures, an on-chip 100-Ω termination
resistor is placed differentially at the receive end.
The PECL output also provide preemphasis for compensating ac loss when driving a cable or PCB backplane
over long distance. The level of the preemphasis is programmable via PRE1 and PRE2 pins. Users can use
software to control the strength of the preemphasis to optimize the device for a specific system requirement.
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