Intel IXF1104 manual 5.6.2.1Transmitter Operational Overview, Datasheet

IXF1104 Quad-Port 10/100/1000 Mbps Ethernet Media Access Controller

speed SerDes and are capable of operating in either an AC- or DC-coupled environment. AC coupling is recommended for this interface to ensure that the correct input bias current is supplied at the receiver.

The SerDes receive interface receives serialized data at 1.25 GHz. The interface is differential with two signals for the receive operation. The equalizer receives a differential signal that is equalized for the assumed media channel. The SerDes transmit and receive interfaces are designed to operate within a 100 Ω differential environment and all terminations are included on the device. The SerDes is capable of operating in either AC- or DC-coupled environments.

5.6.2.1Transmitter Operational Overview

The transmit section of the IXF1104 has to serialize the Ten Bit Interface (TBI) data from the IXF1104 MAC section and outputs this data at 1.25 GHz differential signal levels. The 1.25 GHz differential SerDes signals are compliant with the Small Form Factor Pluggable (SFP) Multi- Source Agreement (MSA).

The transmitter section takes the contents of the data register within the MAC and synchronously transfers the data out, ten bits at a time – Least Significant Bit (LSB) first, followed by the next Most Significant Bit (MSB). When these ten bits have been serialized and transmitted, the next word of 10-bit data from the MAC is ready to be serialized for transmission.

The data is transmitted by the high-speed current mode differential SerDes output stage using an internal 1.25 GHz clock generated from the 125 MHz clock input.

5.6.2.2Transmitter Programmable Driver-Power Levels

The IXF1104 SerDes core has programmable transmitter power levels to enhance usability in any

given application.The SerDes Registers are programmable to allow adjustment of the transmit core driver output power. When driving a 100 Ω differential terminated network, these output power settings effectively establish the differential voltage swings at the driver output.

The “TX Driver Power Level Ports 0 - 3 ($0x784)" allows the selection of four discrete power settings. The selected power setting of these inputs is applied to each of the transmit core drivers on a per-port basis. Table 29 “SerDes Driver TX Power Levels” lists the normalized power settings of the transmit drivers as a function of the Driver Power Control inputs. The normalized current setting is 10 mA, which corresponds to the normalized power setting of 1.0. This is the default setting of the IXF1104 SerDes interface. Other values listed in the Normalized Driver Power Setting column are multiples of 10 mA. For example, with inputs at 1110, the driver power is the following:

.5 x 10 mA = 5 mA.

Table 29. SerDes Driver TX Power Levels

				Normalized
DRVPWRx[3]	DRVPWRx[2]	DRVPWRx[1]	DRVPWRx[0]	Driver Power	Driver Power
				Setting
0	0	1	1	1.33	13.3 mA
NOTE: All other values are reserved.

Datasheet 103

Document Number: 278757

Revision Number: 007

Revision Date: March 25, 2004