Hardware Design Guidelines—Intel®IXP43X Product Line of Network Processors

Figure 32. DDRII Clock Simulation Results: CK Signals

Table 34.

Clock Signal Group Routing Guidelines

 

 

 

 

 

 

Parameter

Definition

 

 

 

 

Signal Group Members

D_CK[2:0] and D_CK_N[2:0]

 

 

 

 

Topology

Differential Pair Point to Point (1 Driver, 4 Receivers)

 

 

 

 

Single Ended Trace Impedance (Zo)

50 Ω

 

Series Resistor

33 Ω

 

 

 

 

Nominal Trace Width1

Internal (Strip Line) 3.5 mils, External (Micro Strip) 5 mils

 

Nominal Pair Spacing (edge to edge) 2

Internal (Strip Line) 10.5 mils, External (Micro Strip) 10 mils

 

Minimum Pair to Pair Spacing

Any layer 20mils

 

 

 

 

Minimum Spacing to Other DDR Signals

20.0 mils

 

 

 

 

Minimum Spacing to non-DDR Signals

25.0 mils

 

 

 

 

Maximum Via Count

5 per trace

 

 

 

 

Total Trace Length

500 mils to 1000 mils

 

 

 

 

DDR_CK to DDR_CK_N Length Matching

Match total length to +/- 10 mils between clocks

 

 

 

 

 

Notes:

 

 

 

1.

Nominal trace width is determined by board physical characteristics and stack-up. This value should

 

 

be verified with the PWB manufacturer to achieve the desired Zo.

 

2.

Nominal pair to pair spacing is determined by board physical characteristics and stack-up. This value

 

 

should be verified with the PWB manufacturer to achieve the desired Zdiff.

 

 

 

 

7.3.3.2Data and Control Groups

The data and control signal group includes D_CB[7:0]/DDR_CB[7:0], D_DQ[31:0] / DDR_DQ[31:0], D_DQS[4:0]/DDR_DQS[4:0], D_DM[4:0]/DDR_DM[4:0]., D_CS[1:0]/ DDR_CS[1:0] and D_CKE[1:0]/DDR_CKE[1:0]. The groups should be routed on

 

Intel® IXP43X Product Line of Network Processors

April 2007

HDG

Document Number: 316844; Revision: 001US

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Intel IXP43X manual Data and Control Groups, Parameter Definition