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Intel
®
820E Chipset
R
38 Design Guide
2.7.2.2. RSL Termination
All RSL signals must be terminated to 1.8 V (V
TERM
) using 27-Ω 1% or 28 Ω 2% resistors at the end of
the channel opposite the MCH. Resistor packs are acceptable. V
TERM
must be decoupled using high-
speed bypass capacitors—one 0.1 µF ceramic chip capacitor per two RSL lines—near the terminating
resistors. Additionally, bulk capacitance is required. Assuming a linear regulator with an approximately
20 ms response time, two 100 µF tantalum capacitors are recommended. The trace length between the
last RIMM and the termination resistors should be less than 3 inches. Length matching in this section of
the channel is not required. The V
TERM
power island should be at least 50 mils wide. This voltage need
not be supplied during Suspend to RAM.
Figure 17. Direct RDRAM Termination
RSL Signals
Terminator
R-packs
direct_rdram_term
V
TERM
Note: It is necessary to compensate for the slight difference in electrical characteristics between a dummy via
and a real via. Refer to Section 2.7.2.7 for more information on via compensation.