DP83953VUL National Semiconductor, DP83953VUL Datasheet - Page 45

• Manufacturer Part Number: DP83953VUL
• Description: IC CTRLR RIC REPEATER 160-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83953VUL

• Controller Type: Ethernet Repeater Interface Controller
• Interface: IEEE 802.3
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 870mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-MQFP, 160-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83953VUL

6.0 Port Block Functions
6.1.1 Magnetics Specifications
This section describes the required magnetics to be used
with RIC2A Twisted pair ports. The new transformer is the
only external magnetics required. In this configuration, a
transformer requires a 1:2 turn ratio on the transmit path
and a 1:1 turn ratio on the receive path. In addition, the
system designer must determine if chokes are necessary.
They may not be when careful layout techniques are
employed.
6.1.2 IEEE Conformance
The RIC2A was tested for IEEE conformance on different
platforms. This testing brought out a number of points that
designers should be aware of when developing a RIC2A
based system. Specifically, designers may want to make
provisions to optimize their systems for conformance to
Receive Noise Immunity and Transmitter Differential Output
Voltage, as these have shown to be the most difficult items
in the specification to meet.
Receiver Differential Noise Immunity
A repeater using the RIC2A may have difficulty meeting all
parameters of Receiver Differential Noise Immunity (IEEE
802.3 section 14.3.1.3.2) without strict layout and design
considerations aimed at reducing the reception of 20, 25
and 30 MHz signals. Even though a system shy of these
specification sections shall function flawlessly in commer-
cial environments, National Semiconductor recommends a
3 pole low-pass Butterworth receive filter with a cut off fre-
quency of 15 MHz for those concerned about full IEEE
compliance. Figure 21 is an example of such a filter. Sys-
tems implementing this filter have been shown to comply
with the noise immunity specification.
(Continued)
Figure 17. AUI Port Connection
45
Filters like this are often packaged within magnetics mod-
ules. These modules are currently available from Halo, Bel-
fuse, Pulse, and Valor magnetics suppliers. This is a point
for reference only. National Semiconductor does not qualify,
recommend or claim conformance with any such device.
Peak Differential Output Voltage (V
Without any resistive loading on the R
RIC2A based repeater will pass all conformance tests with
the possible exception of Peak Differential Output Voltage
(V
loaded and transmitting a packet, and with the system run-
ning at 5.25V in a 0
violate the Peak Differential Output Voltage (V
resistive load) at the upper limit. With all twelve twisted pair
ports loaded and transmitting, and with the system running
at 4.75V in an 80
violate Peak Differential Output Voltage (V
tive load) at the lower limit.
Please note that this parameter is also related to layout
considerations, so these results may not be observed with
every design. Also, the violation of this specification under
these conditions will not affect a normal network. The
RIC2A has undergone endurance testing in many plat-
forms and has not shown any loss of data attributed to out
of spec V
A discussion of V
without the inclusion of comments about the RTX and REQ
pins. The RTX and REQ pins can be used to tune the inter-
nal transmit filter and wave shaping circuitry. The RTX input
can be used to adjust the differential voltage (V
output drivers. By placing a resistor between RTX and V
the peak-to-peak Voltage will be increased. Conversely,
OD
into a resistive load). With only one twisted pair port
OD
.
OD
o
C chamber, the output may marginally
o
C chamber, the output may marginally
on the RIC2A would not be complete
OD
EQ
)
and R
OD
www.national.com
into a resis-
TX
OD
OD
pins, a
) of all
into a
DD
,