Draft 6/5/00
Media Interface Signals
3-3
Copyright 2000 by LSI Logic Corporation. All rights reserved.
The voltage on SD_THR determines the trip point for this
ECL input.
When this pin is tied to GND, the FX interface is disabled
and the TP interface is enabled.
SD_THR
Signal Detect Input Threshold Level Set
The voltage on this pin determines the ECL threshold
level (trip point) for the SD input pin so that the device
can directly interface to both 3.3 V and 5 V fiber optic
transceivers. Typically, this pin is either tied to GND (for
3.3 V operation) or to an external voltage divider (for 5 V
operation).
I
TPO+/FXI-
Twisted-Pair Transmit Output (Positive), or
Fiber Optic Receive Input (Negative)
The TPO+/FXI- pin is shared for the twisted-pair and fiber
optic signals. It functions as the positive signal in the
twisted-pair output or the negative signal in the fiber optic
input.
I/O
TPO-/FXI+
Twisted-Pair Transmit Output (Negative), or
Fiber Optic Receive Input (Positive)
The TPO-/FXI+ pin is shared for the twisted-pair and fiber
optic signals. It functions as the negative signal in the
twisted-pair output or the positive signal in the fiber optic
input.
I/O
TPI+/FXO-
Twisted-Pair Receive Input (Positive), or
Fiber Optic Transmit Output (Negative)
The TPI+/FXO- pin is shared for the twisted-pair and fiber
optic signals. It functions as the positive signal in the
twisted-pair input or the negative signal in the fiber optic
output.
I/O
TPI-/FXO+
Twisted-Pair Receive Input (Negative), or
Fiber Optic Output (Positive)
The TPI-/FXO+ pin is shared for the twisted-pair and fiber
optic signals. It functions as the negative signal in the
twisted-pair input or the positive signal in the fiber optic
output.
I/O