SFP 1000BASE-T RJ-45 FEATURES

SFP Mode

When the internal Gigabit Ethernet transceiver (PHY)

is configured to SFP mode, the PHY interfaces directly

with the host serial/deserial (SERDES) interface. The

host interface transmits and receives serial data

differentially at 1.25Gbps. The copper interface is full

featured and advertises full/half duplex, and

1000Base-T wire speed.

Auto-Negotiation

The CAT-5 copper link negotiates according to the IEEE

802.3 Clause 28, and the SERDES interface negotiates

using Clause 37. The two interfaces advertise

1000Base-T full-duplex, and master/slave

relationships. The master establishes the time control

from its local clock source. The slave however recovers

the clock from the received data stream. The SFP

application is limited to 1000Base-T wire speed only.

Auto-Negotiation on the SERDES link is always

restarted when a change is detected on copper link.

The SFP 1000Base-T features a Serial Interface

(SerDes) Auto-Negotiation Bypass mode. This mode

disables auto-negotiation after 200ms of unsuccessful

attempts with the host, without the need for manually

configuring the auto-negotiation parameters. The

Molex SFP 1000Base-T module will transmit data with

auto-negotiation disabled.

Automatic MDI Crossover

The SFP 1000Base-T transceiver performs a MDI

crossover during Auto-Negotiation eliminating the

need for crossover cables or cross-wired (MDIX) ports.

Automatic Polarity Correction

Should the polarity of receive signals inadvertently

become reversed, the SFP 1000Base-T will

automatically correct them based on the sequence of

idle signals received

Auto Power Savings Mode

When the copper link is lost, the SFP automatically

enters a low power mode reducing the chip power

requirements. Full power mode resumes once the

copper link is re-established.

Serial ID

Serial identification is implemented on the SFP

1000Base-T transceiver. The serial protocol uses a

two-wire I2C interface.

Software Reconfigurable

The SFP 1000Base-T is hardware configured on power-

up. The configuration can be changed by a register

write via a two-wire bus (I2C) at any time. For further

detail, refer to the Molex SFP 1000Base-T software

configuration application note.

1000Base-T RJ-45 Gigabit

Ethernet SFP Copper

Transceiver

74741

AUTO-NEGOTIATION SUMMARY

Auto-Negotiation Features Implemented:

General:

■

SERDES Auto-Negotiation is restarted when a change

is detected on the copper link

■

Auto power savings mode when copper link is lost

Copper RJ-45 Interface:

■

Auto-Negotiation

■

Copper SFP speed 1000Base-T

■

Full duplex

■

Automatic MDI Crossover

■

Master/slave relationships

■

Pause flow control

■

Software reconfigurable

Host SERDES Interface:

■

Differential SERDES interface at 1.25Gpbs

■

Master/slave relationships

■

SERDES recovers the clock from the received data

stream

■

Pause flow control