DP83848C-POE-EK National Semiconductor, DP83848C-POE-EK Datasheet - Page 3

• Manufacturer Part Number: DP83848C-POE-EK
• Description: BOARD EVALUATION DP83848C
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of DP83848C-POE-EK

• Main Purpose: Special Purpose DC/DC, Power Over Ethernet
• Outputs And Type: 1, Isolated
• Power - Output: 24W
• Voltage - Output: 3.3V
• Current - Output: 7.3A
• Voltage - Input: 39 ~ 57V
• Regulator Topology: Flyback
• Frequency - Switching: 250kHz
• Board Type: Fully Populated
• Utilized Ic / Part: LM5072
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Software
No device specific software is required for this board National
does provide the integrity utility; a diagnostic and configura-
tion package at:
www.national.com/appinfo/networks/ethernet_utility.html
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 shall 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.
3
A Note about PoE Input Potentials
PoE applications are typically -48V systems, in which the no-
tations 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 con-
vention 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 datasheet and this
application note, the same positive voltage convention is used
herein.
Schematics of the Evaluation Board
Figure 1, Figure 2 and Figure 3 shows the schematic of the
evaluation board.
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