DM9008AEP_06 DAVICOM [Davicom Semiconductor, Inc.], DM9008AEP_06 Datasheet - Page 45

• Manufacturer Part Number: DM9008AEP_06
• Description: Ethernet Controller with General Processor Interface
• Manufacturer: DAVICOM [Davicom Semiconductor, Inc.]

11. Application Notes
11.1 Network Interface Signal Routing
Place the transformer as close as possible to the RJ-45
connector. Place all the 50Ω resistors as close as possible
to the DM9008A RXI± and TXO± pins. Traces routed
from RXI± and TXO± to the transformer should run in close
pairs directly to the transformer. The designer should be
careful not to cross the transmit and receive pairs. As
always, vias should be avoided as much as possible. The
network interface should be void of any signals other than
the TXO± and RXI± pairs between the RJ-45 to the
transformer and the transformer to the DM9008A.. There
should be no power or ground planes in the area under the
HP Auto-MDIX Application
Preliminary
Version: DM9008AEP-DS-P03
Dec. 14, 2006
Figure 11-1 HP Auto-MDIX
Ethernet Controller with General Processor Interface
network side of the transformer to include the area under the
RJ-45 connector.
active signals. The RJ-45 connector and any unused pins
should be tied to chassis ground through a resistor divider
network and a 2KV bypass capacitor.
The Band Gap resistor should be placed as physically close
as pins 1 and 48 as possible (refer to Figure 11-1 and 11-2).
The designer should not run any high-speed signal near the
Band Gap resistor placement.
Keep chassis ground away from all
DM9008AEP
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