DM385 datasheet(227/281 Pages) TI

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A´´

A = A´ + A´´

A´

DM385, DM388

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SPRS821D – MARCH 2013 – REVISED DECEMBER 2013

8.13.2.3 DDR2 CK and ADDR_CTRL Routing

Figure 8-53 shows the topology of the routing for the CK and ADDR_CTRL net classes. The route is a

balanced T as it is intended that the length of segments B and C be equal. In addition, the length of A

(A'+A'') should be maximized.

Figure 8-53. CK and ADDR_CTRL Routing and Topology

Table 8-57. CK and ADDR_CTRL Routing Specification (1)

NO.

PARAMETER

MIN

TYP

MAX

UNIT

Center-to-center CK-CK spacing

CK/CK skew(1)

Mils

CK A-to-B/A-to-C skew length mismatch(2)

Mils

CK B-to-C skew length mismatch

Mils

Center-to-center CK to other DDR2 trace spacing(3)

CK/ADDR_CTRL nominal trace length(4)

CACLM-50

CACLM

CACLM+50

Mils

ADDR_CTRL-to-CK skew length mismatch

100

Mils

ADDR_CTRL-to-ADDR_CTRL skew length mismatch

100

Mils

Center-to-center ADDR_CTRL to other DDR2 trace spacing(3)

Center-to-center ADDR_CTRL to other ADDR_CTRL trace spacing(3)

ADDR_CTRL A-to-B/A-to-C skew length mismatch(2)

100

Mils

ADDR_CTRL B-to-C skew length mismatch

100

Mils

(1)

The length of segment A = A' + A

′′ as shown in Figure 8-53.

(2)

Series terminator, if used, should be located closest to the device.

(3)

Center-to-center spacing is allowed to fall to minimum (2w) for up to 500 mils of routed length to accommodate BGA escape and routing

congestion.

(4)

CACLM is the longest Manhattan distance of the CK and ADDR_CTRL net classes.

Peripheral Information and Timings

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