Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—Category

7.2.3Control Group

The control signal group includes the signals DDRI_CS[1:0] and DDRI_CKE[1:0]. The following simulations were constructed for the 2 bank x16 device configuration where each signal would have three receivers.

Table 38 identifies the transmission line lengths for the chip select (CS0) topology shown in Figure 43 on page 98. These lengths were chosen as realistic goals given the IXP45X/IXP46X network processors to DDR body to body separation of no more than 500 mils.

Table 38. Control Group Topology Transmission Line Characteristics

Transmission Line

Length

 

 

TL1 (Tpd = 175 ps/in)

~ 600 mils

TL2 (Tpd = 175 ps/in)

~ 50 mils

TL3 (Tpd = 175 ps/in)

~ 1,100 mils

TL4 (Tpd = 175 ps/in)

~ 50 mils

TL5, TL6, TL7 (Tpd = 175 ps/in)

~ 800 mils

TL8, TL9, TL10 (Tpd = 175 ps/in)

~ 300 mils

Figure 43. DDR Control (CS0) Topology: Two-Bank x16 Devices

Intel® IXP45X and Intel® IXP46X Product Line of Network Processors

 

HDD

February 2007

98

Document Number: 305261, Revision: 004

Page 98
Image 98
Intel IXP46X, IXP45X manual Control Group Topology Transmission Line Characteristics