Hardware Design
Figure 32. DDRII Clock Simulation Results: CK Signals
Table 34. | Clock Signal Group Routing Guidelines | ||
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| Parameter | Definition |
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| Signal Group Members | D_CK[2:0] and D_CK_N[2:0] | |
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| Topology | Differential Pair Point to Point (1 Driver, 4 Receivers) | |
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| Single Ended Trace Impedance (Zo) | 50 Ω | |
| Series Resistor | 33 Ω | |
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| 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 | |
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| Minimum Spacing to Other DDR Signals | 20.0 mils | |
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| Minimum Spacing to | 25.0 mils | |
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| Maximum Via Count | 5 per trace | |
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| Total Trace Length | 500 mils to 1000 mils | |
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| DDR_CK to DDR_CK_N Length Matching | Match total length to +/- 10 mils between clocks | |
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| Notes: |
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| 1. | Nominal trace width is determined by board physical characteristics and | |
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| be verified with the PWB manufacturer to achieve the desired Zo. | |
| 2. | Nominal pair to pair spacing is determined by board physical characteristics and | |
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| should be verified with the PWB manufacturer to achieve the desired Zdiff. | |
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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 | 83 |