POEPHYTEREV-I National Semiconductor, POEPHYTEREV-I Datasheet - Page 24

• Manufacturer Part Number: POEPHYTEREV-I
• Description: BOARD EVAL LM5072, DP83848I
• Manufacturer: National Semiconductor
• Series: PHYTER®r

Specifications of POEPHYTEREV-I

• 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: DP83848, LM5072
• Lead Free Status / RoHS Status: Not applicable / Not applicable

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4.0 Architecture
This section describes the operations within each trans-
ceiver module, 100BASE-TX and 10BASE-T. Each opera-
tion consists of several functional blocks and described in
the following:
— 100BASE-TX Transmitter
— 100BASE-TX Receiver
— 10BASE-T Transceiver Module
4.1 100BASE-TX TRANSMITTER
The 100BASE-TX transmitter consists of several functional
blocks which convert synchronous 4-bit nibble data, as pro-
vided by the MII, to a scrambled MLT-3 125 Mb/s serial
data stream. Because the 100BASE-TX TP-PMD is inte-
grated, the differential output pins, PMD Output Pair, can
be directly routed to the magnetics.
125MHZ CLOCK
100BASE-TX
LOOPBACK
Figure 6. 100BASE-TX Transmit Block Diagram
BP_SCR
DIVIDE
TX_CLK
BY 5
MLT[1:0]
24
5B PARALLEL
PMD OUTPUT PAIR
SCRAMBLER
TO SERIAL
The block diagram in Figure 6. provides an overview of
each functional block within the 100BASE-TX transmit sec-
tion.
The Transmitter section consists of the following functional
blocks:
— Code-group Encoder and Injection block
— Scrambler block (bypass option)
— NRZ to NRZI encoder block
— Binary to MLT-3 converter / Common Driver
The bypass option for the functional blocks within the
100BASE-TX transmitter provides flexibility for applications
where data conversion is not always required. The
DP83848I implements the 100BASE-TX transmit state
machine diagram as specified in the IEEE 802.3u Stan-
dard, Clause 24.
4B5B CODE-
ENCODER &
TXD[3:0] /
NRZ TO NRZI
GROUP
TX_EN
ENCODER
TO MLT-3 /
COMMON
DRIVER
BINARY
MUX