3
Figure 3. AFBR-0545Z media converter evaluation board
AFBR-0545Z Circuit Design
The schematic for the AFBR-0545Z media converter board
is shown in Figure 2. The data signal from the twisted
pair medium is routed through magnetic (part of RJ 45
jack)to the IC Plus IP113ALF input media converter input
pins (RXIP and RXIM). The IP113ALF is con gured for 100
Mbps full duplex mode. The transmitter output of the
IP113ALF (FXTDP and FXTDM) is AC coupled to the input
of the Avago AFBR-5972Z transceiver module through
a di erential transmission line with a 100 impedance.
Resistor R103 is not populated because AFBR-5972Z has
an internal 100 resistor for termination (see AFBR-5972Z
data sheet). Resistor R112 provides a 100 termination
for the receiver of the AFBR-5972Z module. The voltage
divider between the IP113ALF and AFBR-5972Z module
biases the IP113ALF PHY chip. Resistors R117 and R118
are needed as termination of the receiver output stage of
AFBR-5972Z. The signal detect (SD) output signal of the
transceiver module is connected to the PHY chip FXSD pin
through the voltage divider formed by resistors R111 and
R116. The FXSD pin is active when the threshold voltage is
higher than 1.35 V.
LED2 and LED1 (in Figure 3) provides visual information
about the presence of supply voltage at AFBR-5972Z
module and RJ 45 jack respectively. LED1 also provides
information about twisted pair link connection. LED2
provides information about the full duplex optical link
connection.
Fast Ethernet Measurement Setup
The Fast Ethernet measurement setup converts the data
signal from the twisted pair domain to the optical domain
and back again to the twisted pair domain. The Fast
Ethernet link is created by connecting the RJ 45 interface
of the media converter board to the network through
a CAT5 patch cable. The duplex POF cable is connected
between the AFBR-5972Z modules, as shown in Figure 4.
The second RJ45 interface is connected to the Ethernet
port of the computer through a CAT5 patch cable.
Figure 4. Fast Ethernet measurement setup
Media Converter
Board
Media Converter
Board
2m POF Cable
Network
AFBR-5972Z
RJ 45
IP113 ALF
LED1
LED2
