GD82559ER Datasheet, PDF (17/94 Pages) Intel Corporation – PCI Controller

3.5
PHY Signals
Networking Silicon —GD82559ER
Symbol
Type
X1
A/I
X2
A/O
TDP
A/O
TDN
RDP
A/I
RDN
ACTLED# OUT
LILED#
OUT
SPEEDLED# OUT
RBIAS100 B
RBIAS10
B
VREF
B
Name and Function
Crystal Input One. X1 and X2 can be driven by an external 3.3 V 25
MHz crystal. Otherwise, X1 may be driven by an external metal-oxide
semiconductor (MOS) level 25 MHz oscillator when X2 is left floating.
Crystal Input Two. X1 and X2 can be driven by an external 3.3 V 25
MHz crystal. Otherwise, X1 may be driven by an external MOS level
25 MHz oscillator when X2 is left floating.
Analog Twisted Pair Ethernet Transmit Differential Pair. These
pins transmit the serial bit stream for transmission on the Unshielded
Twisted Pair (UTP) cable. The current-driven differential driver can be
two-level (10BASE-T) or three-level (100BASE-TX) signals depending
on the mode of operation. These signals interface directly with an
isolation transformer.
Analog Twisted Pair Ethernet Receive Differential Pair. These pins
receive the serial bit stream from the isolation transformer. The bit
stream can be two-level (10BASE-T) or three-level (100BASE-TX)
signals depending on the mode of operation.
Activity LED. The Activity LED pin indicates either transmit or receive
activity. When activity is present, the activity LED is on; when no
activity is present, the activity LED is off.
Link Integrity LED. The Link Integrity LED pin indicates link integrity.
If the link is valid in either 10 or 100 Mbps, the LED is on; if link is
invalid, the LED is off.
Speed LED. The Speed LED pin indicates the speed. The speed LED
will be on at 100 Mbps and off at 10 Mbps.
Reference Bias Resistor (100 Mbps). This pin controls the out
envelope of the 82559ERER when transmitting in the 10 Mbps mode
via the use of a pull-down resistor to ground. A value of 619 Ω pull-
down resistor is adequate is most applications.
Reference Bias Resistor (10 Mbps). This pin controls the out
envelope of the 82559ER when transmitting in the 10 Mbps mode via
the use of a pull-down resistor to ground. A value of 549 Ω pull-down
resistor is adequate is most applications.
Voltage Reference. This pin is connected to a 1.25 V ± 1% external
voltage reference generator. To use the internal voltage reference
source, this pin should be left floating.
NOTE: 619 Ω and 549 Ω for the RBIAS100 and RBIAS10, respectively, are only a recommended values and
should be fine tuned for various designs.
Datasheet
11