Intel 82541PI Design Manual page 16

82541PI(ER) and 82562GZ(GX) Dual Footprint LOM Design Guide
Table 5. Crystal Parameters
Insulation Resistance
Note: A sampling of crystals that meet the specifications outlined for the 82562GZ(GX) is listed below:
Epson-Seiko
Epson-Seiko
Please consult with your Intel representative before implementing a design that uses another type
of clock source. Careful design is required if using a fixed oscillator. Intel discourages the use of
programmable oscillators and ceramic resonators. See
Frequency Using a Frequency Counter"
3.1.1.1 Vibration Mode
Crystals in the frequency range listed in
overtone. Unless there is a special need for third overtone, use fundamental mode crystals.
At any given operating frequency, third overtone crystals are thicker and more rugged than
fundamental mode crystals. Third overtone crystals are more suitable for use in military or harsh
industrial environments. Third overtone crystals require a trap circuit (extra capacitor and inductor)
in the load circuitry to suppress fundamental mode oscillation as the circuit powers up. Selecting
values for these components is beyond the scope of this document.
3.1.1.2 Nominal Frequency
Intel® Ethernet controllers use a crystal frequency of 25.000 MHz. The 25 MHz input is used to
generate a 125 MHz transmit clock for 100BASE-TX and 1000BASE-TX operation; 10 MHz and
20 MHz transmit clocks, for 10BASE-T operation.
3.1.1.3 Frequency Tolerance
The frequency tolerance for an Ethernet physical layer device is dictated by the IEEE 802.3
specification as ±50 parts per million (ppm). This measurement is referenced to a standard
temperature of 25° C.
Note: Intel recommends a frequency tolerance of ±30 ppm.
8
Drive Level 0.5 mW maximum
Aging ±5 ppm per year maximum
500 MΩ minimum at DC 100 V for the 82562GZ(GX)
Package HC49 for the 82562GZ(GX)
MA-406-25.000M-20PF*
MA-406H*
Appendix A, "Measuring LAN Reference
for more information.
Table 5 are available in both fundamental and third
Application Note (AP-468)