82562EZ_08 Datasheet, PDF (38/66 Pages) Intel Corporation – Dual Footprint

82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
4.3
4.3.1
4.3.2
4.4
Layout for the 82547GI(EI) Gigabit Ethernet Controller
Termination Resistors for Designs Based on 82547GI(EI) Gigabit
Ethernet Controller
The four differential pairs are terminated with 49.9 Ω (1% tolerance) resistors, placed near the
82547GI(EI) controller. One resistor connects to the MDI+ signal trace and another resistor
connects to the MDI- signal trace. The opposite ends of the resistors 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.
Light Emitting Diodes for Designs Based on 82547GI(EI) Controller
The 82547GI(EI) 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, take care with care to route the LED traces away from potential sources of EMI noise. In
some cases, it may be desirable to attach filter capacitors.
Physical Layer Conformance Testing
Physical layer conformance testing (also known as IEEE testing) is a fundamental capability for all
companies with Ethernet LAN products. PHY testing is the final determination that a layout has
been performed successfully. If your company does not have the resources and equipment to
perform these tests, consider contracting the tests to an outside facility.
Crucial tests are as follows, listed in priority order:
• Bit Error Rate (BER). Good indicator of real world network performance. Perform bit error
rate testing with long and short cables and many link partners. The test limit is 10-11 errors.
• Output Amplitude, Rise and Fall Time (10/100 Mbps), Symmetry and Droop (1000 Mbps).
For the 82547GI(EI) controller, use the appropriate PHY test waveform.
• Return Loss. Indicator of proper impedance matching, measured through the RJ-45 connector
back toward the magnetics module.
• Jitter Test (10/100 Mbps) or Unfiltered Jitter Test (1000 Mbps). Indicator of clock recovery
ability (master and slave for Gigabit controller).
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