LAN87xx - Ethernet Routing Guidelines

- Keep the trace length difference between TX+ and TX- (or RX+ and RX-) in 700 mils (17 mm).

- Keep RX+/- signal on the top layer, the RX+/- signal should avoid any vias, if possible. Avoid right angle signal trace.

- The crystal/oscillator clock and the switching noise from digital signals should be far away from TX+/-, RX+/- pairs.

- Keep TX, RX differential signals ruing symmetric, equal length, and closely. The trace spacing between TX+ and TX- or between RX+ and RX- pair should be in 8 ~ 10 mils. The better spacing between TX+/- and RX+/- pairs should be larger than 200 mils.