AM1808_1004 Datasheet, PDF (113/264 Pages) Texas Instruments – AM1808 ARM Microprocessor

AM1808
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SPRS653A – FEBRUARY 2010 – REVISED APRIL 2010
6.11.3.5 DDR2/mDDR Keep Out Region
The region of the PCB used for the DDR2/mDDR circuitry must be isolated from other signals. The
DDR2/mDDR keep out region is defined for this purpose and is shown in Figure 6-19. The size of this
region varies with the placement and DDR routing. Additional clearances required for the keep out region
are shown in Table 6-28.
A1
DDR2/mDDR
Device
A1
Region should encompass all DDR2/mDDR circuitry and varies
depending on placement. Non-DDR2/mDDR signals should not be
routed on the DDR signal layers within the DDR2/mDDR keep out
region. Non-DDR2/mDDR signals may be routed in the region
provided they are routed on layers separated from DDR2/mDDR
signal layers by a ground layer. No breaks should be allowed in the
reference ground layers in this region. In addition, the 1.8 V power
plane should cover the entire keep out region.
Figure 6-19. DDR2/mDDR Keepout Region
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Peripheral Information and Electrical Specifications 113
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