Table of Contents
Advertisement
6.
Keep the differential traces lengths equal to reduce signal skew.
7.
Keep the differential traces close and symmetric to reduce noise.
8.
The parallel termination resistors of TD± should be placed near the magnetic.
The parallel termination series resistors of RD± should be placed near the EVA-
X4300.
9.
It is recommended that route the differential traces turn with arcs, and avoid any
vias and corners.
10.
The traces of TX±/ TD± pair should be kept away from RX±/ RD± pair. It is best
to place ground guard traces between these two pair of traces.
11.
We recommend the trace Width/Spacing/Isolation of TX±/ TD± and RX±/ RD±
pairs to be 8 mil/ 10 mil/ >20 mil. And the mismatch of the differential pairs
should be less than ±100 mil.
12.
Do NOT run any digital trace close to and parallel to the differential pairs.
13.
The RJ-45 and output side of transformer should reference to quiet ground
plane (chassis ground) which is isolated from the ground plane of the input side
of transformer and EVA-X4300. Connect this quiet ground plane to system
ground with only one connection (bridge). Do NOT run any signal into this iso-
lated area.
14.
The moat to isolate the quiet ground should be at least 100 mil.
15.
Avoid laying power and ground planes underneath the magnetic to enhance
EMI.
16.
Provide a good path from the RJ-45 connector shell to the chassis ground.
17.
The analog power pins of EVA-X4300, VCCAPLL, VCCABG, VCCA0/1 and
AVDD33_0/1, need to be properly filtered for LAN performance.
18.
It is recommended to connect the analog ground pins of EVA-X4300, VSSAPLL,
VSSABG and VSSA0/1, to an isolated (quiet) analog ground plane, which is
connected to the digital ground plane with a single "Bridge" or Ferrite Bead.
Please refer to section 2.4 for more details.
19.
Place the external resistor of ISET, pin J24, as close to the EVA-X4300 as
possible. And connect another end of the external resistor to the isolated
analog ground plane described above.
20.
Do not run any high-speed signal close to the external resistor of ISET to keep
from interference and coupling.
EVA-X4300 System Design Guide
26
Advertisement
Table of Contents
