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
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There are two DQLMs, one for each byte (16-bit interface). Each DQLM is the longest Manhattan distance of the byte;
therefore:
DQLM0 = DQLMX0 + DQLMY0
DQLM1 = DQLMX1 + DQLMY1
Figure 7-67. DQLM for Any Number of Allowed DDR3 Devices
Table 7-67. DQS[x] and DQ[x] Routing Specification
(1)(2)
NO. PARAMETER MIN TYP MAX UNIT
1 DQ0 nominal length
(3)(4)
DQLM0 mils
2 DQ1 nominal length
(3)(5)
DQLM1 mils
3 DQ[x] skew
(6)
25 mils
4 DQS[x] skew 5 mils
5 DQS[x]-to-DQ[x] skew
(6)(7)
25 mils
6 Center-to-center DQ[x] to other DDR3 trace spacing
(8)(9)
4w
7 Center-to-center DQ[x] to other DQ[x] trace spacing
(8)(10)
3w
8 DQS[x] center-to-center spacing
(11)
9 DQS[x] center-to-center spacing to other net
(8)
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 Section 7.7.2.3.6.2 and Figure 7-67.
(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 Table 7-60.
190 Peripheral Information and Timings Copyright © 2011–2015, Texas Instruments Incorporated
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