Texas Instruments AN-1521 POEPHYTEREV-E, Руководство пользователя, Страница: 2 / 22

Features of the Evaluation Board
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4 Features of the Evaluation Board
Seamless design solution, incorporating DP83848 PHYTER® single port 10/100 Mb/s Ethernet physical
layer transceiver and LM5072 High Power PoE PD and PWM controller.
Ethernet
• Integrated or External magnetics and RJ45
• Minimum configuration requirements:
– 2 PHY Addresses - 01h (default) or 03h
– Status LEDs – board power, others dependant on LED mode selected
– Limited Strap Options – MDIX_EN, LED_CFG, PWR_DWN/INT, MII/RMII Sel
– RESET_N jumper
– PWR_DWN/INT jumper
• Connections for the following interfaces:
– MIl/RMII Interface (IEEE 802.3 standard)
– RJ-45 Cat-V Ethernet cable connector
– JTAG header
– 25MHz_OUT header
– Header for “ribbon cable” connection to MII/RMII
• On-board clock – Crystal/Oscillator Dual Footprint
Power Over Ethernet
• Isolated output voltage: 3.3V
• Maximum output current: 7.3A
• Maximum output power: 24W
• Input voltage ranges:
– PoE input voltage range: 39 to 57V
– AUX input voltage range: 22 to 57V
• Measured maximum efficiency:
– DC to DC converter efficiency: 90% at 6A
– Overall efficiency (including the input diode bridge): 86% at 6A
• Overall Board Size: 5.50” x 3.96” x 0.70”
• Switching frequency: 250 kHz
• Optional input common-mode filter
PCB Layout Considerations
• FR4 material
• Trace symmetry within differential pair (±0.5")
• Differential impedance 100 ohms, ±5%
• Adjacent differential pairs spacing > 2X distance within a differential pair, to minimize cross-talk and
EMI
• Trace length matching between differential pairs not required
• Uniform supply & ground plane
• Void planes under magnetics, except for Chassis GND (at RJ-45 edge only)
• Combination of through-hole and surface mount technology
• Trace/space will be 0.007”/0.008” minimum
• System interface will be via the MII connector, and MII header
• RJ-45 for network connection
• JTAG access via 2x5 header
2 AN-1521 POEPHYTEREV-I / -E Evaluation Board SNOA476C – October 2006 – Revised April 2013
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