82541Pi(Er) Signal Terminations; Light Emitting Diodes For Designs Based On 82541Pi(Er); Schematic For Eeprom Footprints And Lci Connection; Common Eeprom Footprint For Both 82541Pi(Er) And 82562Gz(Gx) - Intel 82541PI Design Manual

82541PI(ER) and 82562GZ(GX) Dual Footprint LOM Design Guide
4.7

82541PI(ER) Signal Terminations

The four differential pairs are terminated with 49.9 Ω (1% tolerance) resistors, placed near the
82541PI(ER) controller. One resistor connects to the MDI+ (MDI positive) signal trace and another
resistor connects to the MDI- (MDI negative) signal trace. The opposite ends of the resistors, using
a wide trace, connect together and to ground through a single 0.1 µF capacitor. The capacitor
should be placed as close as possible to the 49.9 Ω resistors using a wide trace.
Do not vary the suggested component values. Be sure to lay out symmetrical pads and traces for
these components such that the length and symmetry of the differential pairs are not disturbed.
4.8

Light Emitting Diodes for Designs Based on 82541PI(ER)

The 82541PI(ER) controller provides four programmable high-current outputs to directly drive
LEDs for link activity and speed indication. Since the LEDs are likely to be integral to a magnetics
module, route the LED traces away from potential sources of EMI noise. In some cases, it may be
desirable to attach filter capacitors.
4.9

Schematic for EEPROM Footprints and LCI Connection

There are two options for EEPROM footprints. OEMs can choose either a common EEPROM
footprint for the 82541PI(ER), 82562GZ(GX), and ICHx or an independent EEPROM footprint for
each LAN controller.
Figure 14. Common EEPROM Footprint for Both 82541PI(ER) and 82562GZ(GX)
40 Application Note (AP-468)