Intel 82547EI, Design Manual

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82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
7
3.0 Ethernet Component Design Guidelines
These sections provide recommendations for selecting components and connecting special pins.
The main design elements are the 82562EZ(EX) Platform LAN Connect device or the
82547GI(EI) Gigabit Ethernet Controller, an integrated magnetics module with RJ-45 connector,
and a crystal clock source.
3.1 General Design Considerations for Ethernet Controllers
These recommendations apply to all designs, 10/100 or 10/100/1000 Mb/s.
Follow good engineering practices with respect to unused inputs by terminating them with pull-up
or pull-down resistors, unless the data sheet, design guide or reference schematic indicates
otherwise. Do not attach pull-up or pull-down resistors to any balls identified as No Connect.
These devices may have special test modes that could be entered inadvertently.
3.1.1 Crystal Selection Parameters
Quartz crystals are generally considered to be the mainstay of frequency control components due to
their low cost and ease of implementation. They are available from numerous vendors in many
package types and with various specification options.
All crystals used with Intel
®
Ethernet controllers are described as “AT-cut”, which refers to the
angle at which the unit is sliced with respect to the long axis of the quartz stone.
Table 5 lists the crystal electrical parameters and provides suggested values for typical designs. The
parameters listed are described in the following subsections.
Table 5. Crystal Parameters
Parameter Suggested Value
Vibration Mode Fundamental
Nominal Frequency 25,000 MHz at 25
°
C (required)
Frequency Tolerance • ±30 ppm recommended; ±50 ppm across the entire operating
temperature range as required by IEEE specifications
• ±30 ppm required for the 82547GI(EI)
Temperature Stability • ±50 ppm at 0
°
C to 70
°
C
• ±30 ppm at 0
°
C to 70
°
C required for the 82547GI(EI)
Calibration Mode Parallel
Load Capacitance • 16 pF to 20 pF
• 18 pF required for the 82547GI(EI)
Shunt Capacitance 6 pF maximum
Equivalent Series Resistance • 50
Ω
maximum
• 10
Ω
maximum required for the 82547GI(EI)
Drive Level 0.5 mW maximum
Aging ±5 ppm per year maximum