DP83815DVNG/NOPB National Semiconductor, DP83815DVNG/NOPB Datasheet - Page 23

• Manufacturer Part Number: DP83815DVNG/NOPB
• Description: IC CTLR/LAYER INT PCI 144-LQFP
• Manufacturer: National Semiconductor

Specifications of DP83815DVNG/NOPB

• Controller Type: Ethernet Controller, MAC/BIU
• Interface: PCI
• Voltage - Supply: 3.3V
• Current - Supply: 170mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 144-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *DP83815DVNG; *DP83815DVNG/NOPB; DP83815DVNG

Subject to change without notice.
3.0 Functional Description
The 100BASE-TX MLT-3 signal sourced by the TD±
common driver output pins is slew rate controlled. This
should be considered when selecting AC coupling
magnetics
transition times (3 ns < Tr < 5 ns).
The 100BASE-TX transmit TP-PMD function within the
DP83815 is capable of sourcing only MLT-3 encoded data.
Binary output from the TD± outputs is not possible in 100
Mb/s mode.
3.10 100BASE-TX Receiver
The 100BASE-TX receiver consists of several functional
blocks which convert the scrambled MLT-3 125 Mb/s serial
data stream to synchronous 4-bit nibble data that is
provided to the MAC. Because the 100BASE-TX TP-PMD
is integrated, the differential input pins, RD±, can be
directly routed from the AC coupling magnetics.
See Figure 3-8 for a block diagram of the 100BASE-TX
receive function. This provides an overview of each
functional block within the 100BASE-TX receive section.
The Receive section consists of the following functional
blocks:
— ADC
— Input and BLW Compensation
— Signal Detect
— Digital Adaptive Equalization
— MLT-3 to Binary Decoder
— Clock Recovery Module
— NRZI to NRZ Decoder
— Serial to Parallel
— De-scrambler (bypass option)
— Code Group Alignment
— 4B/5B Decoder (bypass option)
— Link Integrity Monitor
— Bad SSD Detection
The bypass option for the functional blocks within the
100BASE-TX receiver provides flexibility for applications
such as 100 Mb/s repeaters where data conversion is not
always required.
to
INVALID CODES
ensure
Name
V
V
V
V
V
V
V
V
V
V
TP-PMD
Table 3-1 4B5B Code-Group Encoding/Decoding
PCS 5B Code-group
Standard
(Continued)
00000
00001
00010
00011
00101
00110
01000
01100
10000
11001
compliant
23
3.10.1 Input and Base Line Wander Compensation
Unlike the DP83223V Twister, the DP83815 requires no
external attenuation circuitry at its receive inputs, RD+/−. It
accepts TP-PMD compliant waveforms directly, requiring
only a 100Ω termination plus a simple 1:1 transformer.
The DP83815 is completely ANSI TP-PMD compliant and
includes Base Line Wander (BLW) compensation. The
BLW compensation block can successfully recover the TP-
PMD defined “killer” pattern and pass it to the digital
adaptive equalization block.
BLW can generally be defined as the change in the
average DC content, over time, of an AC coupled digital
transmission over a given transmission medium. (i.e.
copper wire).
BLW results from the interaction between the low
frequency components of a transmitted bit stream and the
frequency response of the AC coupling component(s)
within the transmission system. If the low frequency
content of the digital bit stream goes below the low
frequency pole of the AC coupling transformers then the
droop characteristics of the transformers will dominate
resulting in potentially serious BLW.
The digital oscilloscope plot provided in Figure 3-9
illustrates the severity of the BLW event that can
theoretically be generated during 100BASE-TX packet
transmission. This event consists of approximately 800 mV
of DC offset for a period of 120 us. Left uncompensated,
events such as this can cause packet loss.
3.10.2 Signal Detect
The signal detect function of the DP83815 is incorporated
to meet the specifications mandated by the ANSI FDDI TP-
PMD Standard as well as the IEEE 802.3 100BASE-TX
Standard
parameters.
Note that the reception of normal 10BASE-T link pulses
and fast link pulses per IEEE 802.3u Auto-Negotiation by
the 100BASE-TX receiver do not cause the DP83815 to
assert signal detect.
Description/4B Value
for
both
voltage
thresholds
Rev O
www.national.com
and
timing