DM385, DM388
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SPRS821D –MARCH 2013–REVISED DECEMBER 2013
8.13.2.2.4 Placement
Figure 8-50 shows the required placement for the processor as well as the DDR2 devices. The
dimensions for this figure are defined in Table 8-51. The placement does not restrict the side of the PCB
on which the devices are mounted. The ultimate purpose of the placement is to limit the maximum trace
lengths and allow for proper routing space. For a 16-bit DDR memory system, the high-word DDR2 device
is omitted from the placement.
Recommended DDR2 Device
Orientation
X
1
X
A1
A1
1
1
X
X
OFFSET OFFSET
Y
Figure 8-50. Device and DDR2 Device Placement
Table 8-51. Placement Specifications
NO.
1
PARAMETER
MIN
MAX
1660
1280
650
UNIT
Mils
Mils
Mils
X + Y(1)(2)
X'(1)(2)
X' Offset(1)(2) (3)
DDR2 keepout region(4)
2
3
4
5
Clearance from non-DDR2 signal to DDR2 keepout region(5)
4
w
(1) For dimension definitions, see Figure 8-48.
(2) Measurements from center of processor to center of DDR2 device.
(3) For 16-bit memory systems, it is recommended that X' offset be as small as possible.
(4) DDR2 keepout region to encompass entire DDR2 routing area.
(5) Non-DDR2 signals allowed within DDR2 keepout region provided they are separated from DDR2 routing layers by a ground plane.
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