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Platform Clock Routing Guidelines
R
Intel
®
855PM Chipset Platform Design Guide
233
Table 63. BCLK/BCLK#[1:0] Routing Guidelines
Parameter
Routing Guidelines
Figure
Notes
Signal Group
HOST_CLK
1
Motherboard Topology
Source Shunt Termination
Reference Plane
Ground Referenced (Contiguous over entire
length)
BCLK Skew Between Agents
500 ps Total Budget: 250 ps for Flight Skew;
100 ps for Pin-to-Pin Skew; 150 ps for Jitter
Figure 130 2, 3, 4, 5
Differential Pair Spacing
7 mils
6, 7
Trace Width
4 mils
8
Spacing to Other Traces
Min = 25 mils
System Board Impedance – Differential
100
± 15%
9
System Board Impedance – Odd Mode
50
± 15%
10
Processor Routing Length – L1, L1’: Clock Driver
to Rs
Max = 0.50 inches
Figure 129
14
Processor Routing Length – L2, L2’: Rs to Rt
Node
Min = 0 inches
Max = 0.20 inches
Figure 129
14
Processor Routing Length – L3, L3’: Rt Node to
Rt
Min = 0 inches
Max = 0.50 inches
Figure 129
14
Processor Routing Length – L4, L4’: Rt Node to
Receiver
Min = 2.0 inches
Max = 8.0 inches
Figure 129
MCH Routing Length – L1, L1’: Clock Driver to Rs Max = 0.50 inches
Figure 129
14
MCH Routing Length – L2, L2’: Rs to Rt Node
Min = 0 inches
Max = 0.20 inches
Figure 129
14
MCH Routing Length – L3, L3’: Rt Node to Rt
Min = 0 inches
Max = 0.50 inches
Figure 129
14
MCH Routing Length – L4, L4’: Rt Node to
Receiver
Min = 2.0 inches
Max = 8.0 inches
Figure 129
Processor L1/L1’ and MCH L1/L1’ Length
Matching
± 10 mils
16
Clock Driver-to-Processor and Clock Driver-to-
MCH Length Matching (L1 + L2 + L4)
- 400 mils ± 50 mils
11
Processor BCLK (L1 + L2 + L4) and BCLK# (L1’
+ L2’ + L4’) Length Matching
± 10 mils
MCH BCLK (L1 + L2 + L4) and BCLK# (L1’ + L2’
+ L4’) Length Matching
± 10 mils
Series Termination Resistor (Rs)
33
± 5%
Figure 129
12
Parallel Termination Resistor (Rt)
49.9
± 1% (for 55
MB impedance)
Figure 129
13
NOTES:
Содержание 855PM
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