AM7968 AMD [Advanced Micro Devices], AM7968 Datasheet - Page 74

• Manufacturer Part Number: AM7968
• Description: TAXIchip Integrated Circuits(Transparent Asynchronous Xmitter-Receiver Interface)
• Manufacturer: AMD [Advanced Micro Devices]

Figure 5-11
70
AMD
Sample Values
Using RG-58A/U, 50
following component values:
5.7 Interfacing to Twisted-Pair Cable
Another low cost alternative twisted pair cable. Twisted pair cable is generally more
lossy than coaxial cable making it suitable only for short distances. To reduce the
possibility of noise being induced along the line, the shielded twisted-pair cable is
recommended.
Using the TAXlchip set with shielded-twisted-pair as the serial medium is very similar to
using it with coaxial cable. The recommended configuration is shown in Figure 5-11,
where each of the components that make up the interface serve the same purpose as in
the AC-coupled TAXl-fiber optic interface shown in Figure 5-9.
Note that with shielded-twisted-pair, only one cable is required to form the link. The
twisted-pair conductors carry the differential pseudo-ECL signals and the shield is
grounded at the Receiver.
Shielded-Twisted Pair Cable Interface
R1+ R2
R1+ R2
186
C = Largest RF Capacitor Available
R1R2
5R2
TAXI
TX
RE
= Z0/2
=
+5 V
Midpoint of Pseudo
7.2 (Z0)
ECL Signal Swing
+
–
RE
TAXIchip Integrated Circuits Technical Manual
coaxial cable, a successful TAXI link was established using the
C
C C
RE
R1 = 68
R2 = 200
RE = 300
C = 0.1 F
= 3.7 V
L, Z0
R1
R2
R1
R2
+5 V
+
–
12330E-18
TAXI
RX