Datasheet

PRODUCTPREVIEW
A1
A1
C B
A
LPDDR
Interface
AM335x
AM3359, AM3358, AM3357
AM3356, AM3354, AM3352
SPRS717E –OCTOBER 2011–REVISED JANUARY 2013 www.ti.com
5.5.2.1.3 LPDDR CK and ADDR_CTRL Routing
Figure 5-35 shows the topology of the routing for the CK and ADDR_CTRL net classes. The length of
signal path AB and AC should be minimized with emphasis to minimize lengths C and D such that length
A is the majority of the total length of signal path AB and AC.
Figure 5-35. CK and ADDR_CTRL Routing and Topology
Table 5-39. CK and ADDR_CTRL Routing Specification
(1)(2)
NO. PARAMETER MIN TYP MAX UNIT
1 Center-to-center CK spacing 2w
2 CK differential pair skew length mismatch
(2)(3)
25 mils
3 CK B-to-CK C skew length mismatch 25 mils
4 Center-to-center CK to other LPDDR trace spacing
(4)
4w
5 CK and ADDR_CTRL nominal trace length
(5)
CACLM-50 CACLM CACLM+50 mils
6 ADDR_CTRL-to-CK skew length mismatch 100 mils
7 ADDR_CTRL-to-ADDR_CTRL skew length mismatch 100 mils
8 Center-to-center ADDR_CTRL to other LPDDR trace spacing
(4)
4w
9 Center-to-center ADDR_CTRL to other ADDR_CTRL trace spacing
(4)
3w
10 ADDR_CTRL A-to-B and ADDR_CTRL A-to-C skew length mismatch
(2)
100 mils
11 ADDR_CTRL B-to-C skew length mismatch 100 mils
(1) CK represents the clock net class, and ADDR_CTRL represents the address and control signal net class.
(2) Series terminator, if used, should be located closest to the AM335x device.
(3) Differential impedance should be Zo x 2, where Zo is the single-ended impedance defined in Table 5-32.
(4) Center-to-center spacing is allowed to fall to minimum (w) for up to 500 mils of routed length to accommodate BGA escape and routing
congestion.
(5) CACLM is the longest Manhattan distance of the CK and ADDR_CTRL net classes.
152 Peripheral Information and Timings Copyright © 2011–2013, Texas Instruments Incorporated
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