82563EB Datasheet, PDF (37/52 Pages) Intel Corporation – Intel® 82563EB/82564EB Gigabit Ethernet Controllers

82563EB/82564EB Gigabit Platform LAN Connect Networking Silicon
4.7
Crystal
The quartz crystal is strongly recommended as a low cost and high performance choice with the
82563EB/82564EB device. Quartz crystals are the mainstay of frequency control components and
are available from numerous vendors in many package types with various specification options
Table 31. Crystal Parameters
Parameter
Suggested Value
Vibrational Mode
Fundamental
Nominal Frequency
25.000 MHz
Frequency Tolerance
• ±30 ppm recommended
• ±50 ppm across the entire operating
temperature range (required by IEEE
specifications)
Temperature Tolerance
±30 ppm
Calibration Mode
Parallel
Load Capacitance
27 pF
Shunt Capacitance
6 pF maximum
Equivalent Series Resistance 50 Ω maximum
Drive Level
750 µW
Aging
±5 ppm per year maximum
Conditions
at 25° C
at 25° C
at 0° C to 70° C
at 25 MHz
4.7.1
External Clock Oscillator
If using an external oscillator to provide a clock to the 82563EB/82564EB, the connection shown
in Figure 9 must be used. Note that the XTAL2 output of the 82563EB/82564EB must not be
connected. The XTAL1 input receives the output of the oscillator directly; AC coupling is not
recommended.
82563EB/82564EB
XTAL2
XTAL1
3.3V
Figure 9. External Clock Oscillator Connectivity to 82563EB/82564EB
31