An Important Note About the Maximum Power Capability and Cable Usage
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Ethernet Performance
The DP83848 PHYTER® supports line speed Ethernet network communications. Signal quality, which
affects IEEE compliance, can vary depending on board layout, power supplies, and components used,
esp. isolation magnetics.
Software
No device specific software is required for this board.
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An Important Note About the Maximum Power Capability and Cable Usage
The maximum output power is 24W. The user must make sure that the Power Sourcing Equipment (PSE)
in use can provide at least 30W.
Important: Please note that the CAT-5 cable may not support the said power over two pairs of twisted
wires under strict safety considerations. Users will select the proper cable wires to support the design
power level without compromising the applicable safety standards. Using an improper cable at such power
levels may violate safety regulations and may cause damage.
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A Note about PoE Input Potentials
PoE applications are typically -48V systems, in which the notations GND and -48V normally refer to the
high and low input potentials, respectively. However, for easy readability, the LM5072 datasheet was
written in the positive voltage convention with positive input potentials referenced to the VEE pin of the
LM5072. Therefore, when testing the evaluation board with a bench power supply, the negative terminal of
the power supply is equivalent to the PoE system’s -8V potential, and the positive terminal is equivalent to
the PoE system ground. To prevent confusion between the data sheet and this application note, the same
positive voltage convention is used herein.
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Schematics of the Evaluation Board
Figure 1
,
Figure 2
, and
Figure 3
shows the schematic of the evaluation board.
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AN-1521 POEPHYTEREV-I / -E Evaluation Board
SNOA476C – October 2006 – Revised April 2013
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