AM3894CCYG120 Datasheet, PDF (163/308 Pages) Texas Instruments – AM389x Sitara ARM Processors

www.ti.com
AM3894
AM3892
SPRS681E – OCTOBER 2010 – REVISED JULY 2012
8.3.1.2.4 Placement
Figure 8-7 shows the required placement for the processor as well as the DDR2 devices. The dimensions
for this figure are defined in Table 8-5. 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
X
Orientation
X¹
A1
A1
X¹
X¹
Y
OFFSET OFFSET
Figure 8-7. AM389x Device and DDR2 Device Placement
Table 8-5. Placement Specifications
NO.
PARAMETER
1 X + Y ^{(1) (2)}
2 X^{' (1) (2)}
3 X^' Offset^{(1) (2) (3)}
4 DDR2 keepout region⁽⁴⁾
5 Clearance from non-DDR2 signal to DDR2 keepout region⁽⁵⁾
MIN
MAX UNIT
1660 Mils
1280 Mils
650 Mils
4
w
(1) For dimension definitions, see Figure 8-5.
(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.
Copyright © 2010–2012, Texas Instruments Incorporated
Submit Documentation Feedback
Product Folder Link(s): AM3894 AM3892
Peripheral Information and Timings 163