TLK2711JRZQE Datasheet, PDF (9/27 Pages) Texas Instruments – 1.6 TO 2.7 GBPS TRANSCEIVER

TLK2711
1.6 TO 2.7 GBPS TRANSCEIVER
SLLS501 – SEPTEMBER 2001
detailed description (continued)
high-speed data output
The high-speed data output driver consists of a voltage mode logic (VML) differential pair optimized for a 50-Ω
impedance environment. The magnitude of the differential pair signal swing is compatible with pseudo emitter
coupled logic (PECL) levels when ac-coupled. The line can be directly-coupled or ac-coupled. Refer to
Figure 11 and Figure 12 for termination details. The outputs also provide preemphasis to compensate for ac
loss when driving a cable or PCB backplane trace over a long distance (see Figure 4). The level of preemphasis
is controlled by PRE as shown in Table 2 .
V(TERM)
VOD(p)
VOD(d)
Table 2. Programmable Preemphasis
PRE
0
PREEMPHASIS LEVEL(%)
VOD(P), VOD(D)^†
5%
Bit
Time
Bit
Time
VOD(p)
VOD(d)
Figure 4. Output Voltage Under Preemphasis (|VTXP–VTXN|)
1
20%
† _{VOD(p) : Voltage swing when there is a}
transition in the data stream
VOD(d): Voltage swing when there is no
transition in the data stream.
receive interface
The receiver portion of the TLK2711 accepts 8-bit/10-bit encoded differential serial data. The interpolator and
clock recovery circuit locks to the data stream and extract the bit rate clock. This recovered clock is used to
retime the input data stream. The serial data is then aligned to two separate 10-bit word boundaries, 8-bit/10-bit
decoded and output on a 16-bit wide parallel bus synchronized to the extracted receive clock. The data is
received LSB (RXD0) first.
receive data bus
The receive bus interface drives 16-bit wide single-ended TTL parallel data at the RXD[0:15] terminals. Data
is valid on the rising edge of the RXCLK. The RXCLK is used as the recovered word clock. The data, RKLSB,
RKMSB, and clock signals are aligned as shown in Figure 5. Detailed timing information can be found in the
switching characteristics table.
RXCLK
RXD[0–15]
tsu
th
RKLSB, RKMSB
Figure 5. Receive Timing Waveform
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