Agp Clock Layout - Intel 440GX Design Manual

Motherboard Layout and Routing Guidelines
2.9.6.5

AGP Clock Layout

Series Termination: 22 Ohm series termination should be used for the AGP clocks.
Layout guidelines: The feedback clock trace length equals the standard clock motherboard trace
length plus the card trace length.
Figure 2-31. AGP Clock Layout
22 Ohm resistor - AGP connector
22 Ohm resistor - 82443GX (feedback)
Note: One driver. The signal splits at the 82443GX, each half of the trace goes through a 22 Ohm resistor,
and then to their respective loads. If the graphics chip is down on the motherboard, the trace length
to the graphics chip and the feedback trace length to the 82443GX will both be the same length.
2-34
BX
22ohm
GCLKOUT
22ohm
GCLKIN
Net Trace Length
AGPCLK
Min
A 0.5"
A + 3.3" 0.5"
®
Intel 440GX AGPset Design Guide
Card Trace
Max
Length
12" ~3.3"
15.3" NA