Intel Pentium 4 User Manual

AGP Interface Routing
R
116 Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide
7.1.3 AGP Interfaces Trace Length Summary
The 2X/4X Timing Domain Signals can be routed with 5 mil spacing when breaking out of the
MCH. The routing must widen to the documented requirements within 0.3 inches of the MCH
package.
When matching trace length for the AGP 4X interface, all traces should be matched from the ball
of the MCH to the pin on the AGP connector. It is not necessary to compensate for the length of
the AGP signals on the MCH package.
Reduce line length mismatch to insure added margin. In order to reduce trace to trace coupling
(crosstalk), separate the traces as much as possible. All signals in a signal group should be routed
on the same layer. The trace length and trace spacing requirements must not be violated by any
signal. Trace length mismatch for all signals within a signal group should be as close to zero as
possible to provide timing margin.
Table 26. AGP 2.0 Routing Summary
Signal Maximum
Length
Trace Spacing
(5 mil traces)
Length
Mismatch
Relative To
1X Timing Domain 7.5 inches 5 mils No requirement N/A
2X/4X Timing
Domain Set #1
7.25 inches 20 mils
3
±0.125 inches
2
AD_STB0 and
AD_STB0#
2X/4X Timing
Domain Set #2
7.25 inches 20 mils
3
±0.125 inches
2
AD_STB1 and
AD_STB1#
2X/4X Timing
Domain Set #3
7.25 inches 20 mils
3
±0.125 inches
2
SB_STB and
SB_STB#
2X/4X Timing
Domain Set #1
6 inches 15 mils
1,3
±0.25 inches
2
AD_STB0 and
AD_STB0#
2X/4X Timing
Domain Set #2
6 inches 15 mils
1,3
±0.25 inches
2
AD_STB1 and
AD_STB1#
2X/4X Timing
Domain Set #3
6 inches 15 mils
1,3
±0.25 inches
2
SB_STB and
SB_STB#
2X/4X Timing
Domain Set #1
6 inches 20 mils
1,4
±0.25 inches
2
AD_STB0 and
AD_STB0#
2X/4X Timing
Domain Set #2
6 inches 20 mils
1,4
±0.25 inches
2
AD_STB1 and
AD_STB1#
2X/4X Timing
Domain Set #3
6 inches 20 mils
1,4
±0.25 inches
2
SB_STB and
SB_STB#
NOTES:
1. Each strobe pair must be separated from other signals by at least 20 mils.
2. Each strobe pair must be the same length.
3. These guidelines apply to board stack-ups with 10% impedance tolerance.
4. These guidelines apply to board stack-ups with 15% impedance tolerance

Intel Pentium 4 Specifications

General

Brand	Intel
Model	Pentium 4
Category	Computer Hardware
Language	English