Intel
ยฎ
EP80579 Integrated Processor Product Line May 2010
Order Number: 320068-005US 122
System Memory Interface (DIMM)โIntel
ยฎ
EP80579 Integrated Processor Product Line
Board Routing Guidelines
Total Trace Length (TTL) = (L
PKG
+
L
BREAK
+ L
ROUTE
+ L
D2D
)
2.0 in - 6.0 in
Max TTL (DQS/DQS#) =
Min TTL (DQ/DM) +
400 mils
Figure 77
L
PKG
See the Intel
ยฎ
EP80579 Integrated Processor Product Line Datasheet for
package length information.
L
BREAK
B = 0.8 in (max)
L
ROUTE
C = 2.0 in - 4.0 in
Calculate while taking into
account Strobe Max Trace
Length (Max TTL)
L
D2D
D = 0.8 in (max) (including both DIMMsโ break-in fields)
Length/Skew Matching Rules
Length Tuning Requirements
โข Only length matching
is required within each
Byte lane. No signal
length matching is
required outside the
Byte lane. For
example, any signal
within Data Byte Lane
0 (DQ [0...7]) need not
be length matched to
DQS1
โขDQ/DM should match
each other to 20 mils
or less within the same
byte lane. (See
Figure 78)
โข The trace length
difference between
DQS and DQS# should
not be more than 10
mils. - that is,
DQS[x] =
DQS[x]#ยฑ10 mils, x = 0..
8
โข Length match the data
strobes (DQS/DQS#)
to the associated data
mask and data (DQ/
DM) signals for each
Data Byte Lane:
Max(DQS/DQS#) =
Min(DQ/DM[x]) +
400 mils, x = 0.. 8
โข Length match all DIMM-to-DIMM (D2D) signals (DQ/DM/DQS/DQS#)
to 10 mils or less within the same byte lane
Routing Rules
Layer Routing Requirements
Signals within a data byte lane must be routed on the
same layer.
Table 39. Data and Strobe Signal Group Routing Guidelines (Sheet 2 of 2)
Parameter
Routing Guidelines Figure
Data Byte Lane
Data & Data Mask Strobe