Intel 820E Benutzerhandbuch

Intel

820E Chipset

Design Guide

171

For line section D (DRCG to last RIMM), the CTM/CTM# must be length-matched within ±2 mils.
(Exact matching is recommended.) For section C, ±2 mil trace length matching is required for the
CFM/CFM# signals.

Note: The total trace length matching for the entire CTM/CTM# signal trace (sections A+B+D) and for the

CFM/CFM# signal trace (sections A+B) is ±2 mils. (Exact length matching is recommended.)

Figure 91. Differential Clock Routing Diagram (Sections A, C & D)

Ground

CLOCK

CLOCK#

Ground

Ground/Power Plane

22 mils

14 mils

6 mils

4.5 mils

2.1 mils

1.4 mils

diff_clk_routing

Figure 92. Non-Differential Clock Routing Diagram (Section B)

Ground

CLOCK/CLOCK#

Ground

Ground/Power Plane

10 mils

18 mils

6 mils

4.5 mils

2.1 mils

1.4 mils

non-diff_clk_routing

The CFM/CFM# differential pair signals require termination using either 27

Ω,

1% or 28

Ω,

2% resistors

and a 0.1 µF capacitor, as shown in the following figure.

Figure 93. Termination for Direct RDRAM* Clocking Signals CFM/CFM#

rambus_clk_term

CFM

CFM#

0 .1 µF