Mchip Ethernet

    From Ethernet FAQ:

    What care should be taken to prevent Link termination on my board?

    a. The internal analog circuitry in the PHY module requires that an external resistor (2.26 kÙ) be attached from RBIAS to ground. The resistor influences the TPOUT+/- signal amplitude. It should be placed as close as possible to the chip with no adjacent signal traces to prevent noise capacitive coupling into the pin. It is recommended that the resistor be a surface mount type.

    b. The transformers should have at least the isolation rating as specified in the datasheet to protect against static voltages and meet IEEE 802.3 isolation requirements.

    c. The Ethernet module is designed to work with a 25MHz 50ppm crystal and hence that configuration has been made to provide exact 25 MHz