When creating a new system design with an
Ethernet PHY, follow this schematic capture procedure:
- Use the 'Strap Tool' tab from the Schematic Checklist to select the correct external
bootstrap resistors.
- Select desired PHY hardware
configurations described in Section 7.5.1.
- Go through and use the 'Pinwise Checklist' tab Schematic Checklist as a guide for your schematic
design.
- Use DP83TC812, DP83TC813, and DP83TC814: Configuring for Open Alliance
Specification Complianceas a guide for selecting components for the MDI circuir
connected to the TRD_M and TRD_P pins.
The following layout procedure must be
followed:
- Locate the PHY near the edge of the board
so that short MDI traces can be routed to the desired connector.
- Place the MDI external components: CMC,
DC-blocking capacitors, CM termination, MDI-coupling capacitor, and ESD shunt.
- Create metal pour keepout under the CMC
on the top layer and at least one layer beneath the top later.
- The MDI TRD_M and TRD_P traces are routed
with 100Ω differential.
- Place the clock source near the XI and XO
pins.
- In MII, RMII, or RGMII mode, the xMII
pins are routed 50Ω and are single-ended with reference to ground.
- The transmit path xMII pins are routed
such that setup and hold timing does not violate the PHY requirements.
- The receive path xMII pins are routed
such that setup and hold timing does not violate the MAC requirements.
- In SGMII mode, the xMII RX_P, RX_M, TX_P,
and TX_M pins are routed 100Ω differential.
- Place the MDIO pullup close to the
PHY.
- Go through 'Layout
Checklist' tab from the Schematic Checklist to guide your design.