SLXT970AQC.B11-831643 Cortina Systems Inc, SLXT970AQC.B11-831643 Datasheet - Page 42

• Manufacturer Part Number: SLXT970AQC.B11-831643
• Manufacturer: Cortina Systems Inc

Specifications of SLXT970AQC.B11-831643

• Number Of Receivers: 1
• Data Rate: 10/100Mbps
• Operating Supply Voltage (typ): 5V
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (max): 5.25V
• Operating Supply Voltage (min): 4.75V
• Mounting: Surface Mount
• Pin Count: 64
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Lead Free Status / RoHS Status: Not Compliant

Intel
3.3
3.3.1
3.3.2
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®
LXT970A Dual-Speed Fast Ethernet Transceiver
Design Recommendations
The LXT970A Transceiver is designed in accordance with IEEE requirements and provides
outstanding receive Bit Error Ratio (BER) and long-line-length performance. Lab tests show that
the LXT970A Transceiver performs well beyond the required distance of 100 meters. Ensuring
maximum performance from the LXT970A Transceiver requires attention to detail and good
design practices. Refer to the LXT970 Design and Layout Guide for detailed design and layout
information.
General Design Guidelines
Adherence to generally accepted design practices is essential to minimize noise levels on power
and ground planes. Up to 50 mV of noise is considered acceptable. 50 to 80 mV of noise is
considered marginal. High-frequency switching noise can be reduced, and its effects can be
eliminated, by following these simple guidelines throughout the design:
Power Supply Filtering
Power supply ripple and digital switching noise on the VCC plane can cause EMI problems and
degrade line performance. It is generally difficult to predict in advance the performance of any
design, although certain factors greatly increase the risk of having these problems:
Many of these issues can be improved by following good general design guidelines. Intel also
recommends filtering between the power supply and the analog VCC pins of the
LXT970A Transceiver. Filtering has two benefits. First, it keeps digital switching noise out of the
analog circuitry inside the LXT970A Transceiver, which helps line performance. Second, if the
VCC planes are laid out correctly, it keeps digital switching noise away from external connectors,
reducing EMI problems.
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Fill in unused areas of the signal planes with solid copper and attach them with vias to a VCC
or ground plane that is not located adjacent to the signal layer.
Use ample bulk and decoupling capacitors throughout the design (a value of .01 μF is
recommended for decoupling caps).
Provide ample power and ground planes.
Provide termination on all high-speed switching signals and clock lines.
Provide impedance matching on long traces to prevent reflections.
Route high-speed signals next to a continuous, unbroken ground plane.
Filter and shield DC-DC converters, oscillators, etc.
Do not route any digital signals between the LXT970A Transceiver and the RJ-45 connectors
at the edge of the board.
Do not extend any circuit power and ground plane past the center of the magnetics or to the
edge of the board. Use this area for chassis ground, or leave it void.
Poorly-regulated or over-burdened power supplies.
Wide data busses (>32-bits) running at a high clock rate.
DC-to-DC converters.
Datasheet