
Intel IXP2800 and IXP2850 Network Processors
Electrical Specifications
106
Datasheet
Figure 14 shows the timing goals for the IXP2800/IXP2850 QDRII interface. All timing references
are the rising edges of C and C# or K and K#, for receiver and transmitter, respectively.
Note:
The system designer must ensure that the design implementation meets the SRAM
K-clock-to-C-clock timing relationship, as specified in the SRAM datasheet. This may require
additional trace routing on the baseboard to the C_0/1 clock, to ensure that it always lags the
Kclock.
Table 43 lists the QDR clock skew and
Figure 14 shows timing goals for the QDRII interface.
Table 42. QDR Signal Timing
QDRII
Frequency
233 MHz
200 MHz
167 MHz
133 MHz
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
Input Timing
Setup Time1 , 2 (ns)
1. Not tested. Guaranteed by simulations
2. The specified setup time is negative, which means that the data can arrive at the pins up to the specified time after the rising
-0.70
-0.77
-0.97
-1.27
1.45
1.73
2.03
2.43
Output Timing
-0.65
-0.9
-1.10
-1.37
0.65
0.9
1.10
1.37
K_0/1 to Output Skew at
3. The C4 Bump is the connection point of the silicon die to the package. This parameter specifies the skew between K0 and K1
clock and Write Data, Address, and Write/Read Port Select output signals, but does not include the mismatch introduced by
the package substrate routing.
-0.19
0.19
-0.20
0.20
-0.22
0.22
-0.23
0.23
K_0/1 to Output Skew at
4. This parameter specifies the skew between K0 and K1 clock and Write Data, Address, and Write/Read Port Select output
signals, including the mismatch introduced in the package substrate routing.
-0.28
0.28
-0.29
0.29
-0.31
0.31
-0.32
0.32
Table 43. QDR Clock Skew (Sheet 1 of 2)
Description1, 2
166 MHz
200 MHz
233 MHz
Min
Max
Min
Max
Min
Max
K Rise to K# Rise 3
2.78 ns
3.22 ns
2.30 ns
2.70 ns
1.81 ns
2.19 ns
2.78 ns
3.22 ns
2.30 ns
2.70 ns
1.81 ns
2.19 ns
2.78 ns
3.22 ns
2.30 ns
2.70 ns
1.81 ns
2.19 ns
2.78 ns
3.22 ns
2.30 ns
2.70 ns
1.81 ns
2.19 ns
-0.18 ns
0.18 ns
-0.15 ns
0.15 ns
-0.14 ns
0.14 ns
-0.18 ns
0.18 ns
-0.15 ns
0.15 ns
-0.14 ns
0.14 ns
-0.18 ns
0.18 ns
-0.15 ns
0.15 ns
-0.14 ns
0.14 ns