![](http://datasheet.mmic.net.cn/250000/TSB14AA1_datasheet_15839997/TSB14AA1_28.png)
6
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8
6.2.4
Backplane Transmit Data Timing
Edge separation is the minimum required time between any two consecutive transitions of the backplane bus signals,
as they appear from the output of the transmitters, whether they are transitions on the same signal or transitions on
the two separate signals. A minimum edge separation is required to ensure proper operation of the data strobe
bit-level encoding mechanism. TDATA and TSTRB have the relationship shown in Figure 6
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7 and Table 6
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10.
t(2)
t(2)
t(1)
TDATA
TSTRB
t(2)
t(2)
t(1)
t(1)
t(1)
Figure 6
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7. Minimum Edge Separation
Table 6
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10. TSB14AA1A to Backplane Transceiver Timing
PARAMETER
98.304 MHz
49.152 MHz
t(1)
t(2)
This parameter is based on a maximum total transmit skew of 2 ns.
Bit cell period for data
9.44 ns minimum
19.44 ns minimum
Transmit (Tx) edge separation
8.65 ns minimum
18.65 ns minimum
6.2.5
Backplane Receive Data Timing
The receiver typically uses the transitions on the incoming bus signals RDATA and RSTRB to derive a clock at the
code bit frequency to extract the NRZ signal on RDATA. This clock can be derived by performing an exclusive-OR
(XOR) of RDATA and RSTRB.
The bus signals, as they appear from the backplane transceiver media and into the receiver, should fall within the
timing constraints outlined by Figure 6
–
8.
RDATA
RSTRB
t(3)
t(1)
t(1)
t(1)
t(1)
t(2)
t(3)
t(2)
Figure 6
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8. Backplane Receive Data Timing
Table 6
–
11. TSB14AA1A to Backplane Transceiver Timing
PARAMETER
98.304 MHz
49.152 MHz
t(1)
t(2)
t(3)
This parameter is based on a maximum total transmit skew of 2 ns and a maximum backplane skew of 0.5 ns.
This assumes total receive skew is less than receive edge separation (i.e., some skew margin exists).
Bit cell period
10.1715 ns nominal
20.34 nominal
Receive (Rx) edge separation
3.4 ns minimum
16.3 ns maximum
3.4 ns minimum
36.6 ns maximum