DQLMY0
1
0
DQLMX1
DQ1
DQ0
DQLMX0
DQ[8:15], DM1, DQS1
DQ[0:7], DM0, DQS0
DQLMY1
DQ0 - DQ1 represent data bytes 0 - 1.
AM3359, AM3358, AM3357, AM3356, AM3354, AM3352
SPRS717H – OCTOBER 2011 – REVISED MAY 2015
There are two DQLMs, one for each byte (16-bit interface). Each DQLM is the longest Manhattan distance of the byte;
therefore:
DQLM0 = DQLMY0
DQLM1 = DQLMY1
Figure 7-67. DQLM for Any Number of Allowed DDR3 Devices
Table 7-67. DQS[x] and DQ[x] Routing Specification
NO.
PARAMETER
MIN
TYP
MAX
UNIT
1
DQ0 nominal length
DQLM0
mils
2
DQ1 nominal length
DQLM1
mils
3
DQ[x] skew
25
mils
4
DQS[x] skew
5
mils
5
DQS[x]-to-DQ[x] skew
25
mils
6
Center-to-center DQ[x] to other DDR3 trace spacing
4w
7
Center-to-center DQ[x] to other DQ[x] trace spacing
3w
8
DQS[x] center-to-center spacing
9
DQS[x] center-to-center spacing to other net
4w
(1) DQS[x] represents the DQS0 and DQS1 clock net classes, and DQ[x] represents the DQ0 and DQ1 signal net classes.
(2) External termination disallowed. Data termination should use built-in ODT functionality.
(3) DQLMn is the longest Manhattan distance of a byte. For definition, see
and
(4) DQLM0 is the longest Manhattan length for the DQ0 net class.
(5) DQLM1 is the longest Manhattan length for the DQ1 net class.
(6) Length matching is only done within a byte. Length matching across bytes is not required.
(7) Each DQS clock net class is length matched to its associated DQ signal net class.
(8) Center-to-center spacing is allowed to fall to minimum for up to 1250 mils of routed length.
(9) Other DDR3 trace spacing means signals that are not part of the same DQ[x] signal net class.
(10) This applies to spacing within same DQ[x] signal net class.
(11) DQS[x] pair spacing is set to ensure proper differential impedance. Differential impedance should be Z
o
x 2, where Z
o
is the single-
ended impedance defined in
190
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