Intel IXF1104 - Manual (Page 105)

Intel
®
IXF1104 4-Port Gigabit Ethernet Media Access Controller
105 Datasheet
Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005
5.6.2.3 Receiver Operational Overview
The receiver structure performs Clock and Data Recovery (CDR) on the incoming serial data
stream. The quality of this operation is a dominant factor for the Bit Error Rate (BER) system
performance. Feed forward and feedback controls are combined in one receiver architecture for
enhanced performance. The data is over-sampled and a digital circuit detects the edge position in
the data stream. A signal is not generated if an edge is not found. A feedback loop takes care of
low-frequency jitter phenomenon of unlimited amplitude, while a feed forward section suppresses
high-frequency jitter having limited amplitude. The static edge position is held at a constant
position in the over-sampled by a constant adjustment of the sampling phases with the early and
late signals.
5.6.2.4 Selective Power-Down
The IXF1104 MAC offers the ability to selectively power-down any of the SerDes TX or RX ports
that are not being used. This is done via
“TX and RX Power-Down ($0x787)” on page 220 .
5.6.2.5 Receiver Jitter Tolerance
The SerDes receiver architecture is designed to track frequency mismatch, recover phase, and is
tolerant of low-frequency data jitter.
Figure 23 specifies the SerDes core receiver sinusoidal jitter
tracking capabilities.
1 0 1 1 2.0 20 mA
1 1 0 1 1.0 10 mA
1 1 1 0 0.5 5 mA
Table 29. SerDes Driver TX Power Levels
DRVPWRx[3] DRVPWRx[2] DRVPWRx[1] DRVPWRx[0]
Normalized
Driver Power
Setting
Driver Power
NOTE: All other values are reserved.