Datasheet

10
LTC1686/LTC1687
APPLICATIONS INFORMATION
WUU
U
1686/87 F11a
DRIVER
INPUT
RECEIVER
OUTPUT
10ns/DIV
2V/DIV
2V/DIV
Figure 11a. 100 Feet of Category 5 UTP: 50Mbps
DC and AC attenuation over long distances. Figure 14a
shows a 1µs pulse propagated down 4000 feet of category
5 UTP. Notice the significant attenuation at the receiver
input and the clean pulse at the receiver output. The DC
attenuation is due to the parasitic resistance of the cable.
Figure 14b shows a 1Mbps square wave over the same
4000 feet of cable.
1686/87 F12
DRIVER
INPUT
RECEIVER
OUTPUT
100ns/DIV
2V/DIV
2V/DIV
Figure 12. 1000 Feet of Category 5 UTP: 4Mbps
1686/87 F13
DRIVER INPUT
DIFFERENTIAL
RECEIVER
INPUT
RECEIVER
OUTPUT
20ns/DIV
2V/DIV
2V/DIV
2V/DIV
1685 F11b
RECEIVER
INPUT
DRIVER
INPUT
RECEIVER
OUTPUT
20ns/DIV
2V/DIV
5V/DIV
2V/DIV
CABLE DELAY
Figure 11b. 100 Feet of Category 5 UTP: 20ns Pulse
Figure 13. 100 Feet of Telephone Grade UTP: 30Mbps
1685 F14a
RECEIVER
INPUT
DRIVER
INPUT
RECEIVER
OUTPUT
1µs/DIV
1V/DIV
5V/DIV
2V/DIV
CABLE DELAY
Figure 14a. 4000 Feet of Category 5 UTP 1µs Pulse
1685 F14b
DRIVER
INPUT
RECEIVER
OUTPUT
1µs/DIV
5V/DIV
2V/DIV
Figure 14b. 4000 Feet of Category 5 UTP 1Mbps Square Wave
1.6Mbps Over 8000 Feet (1.5 Miles)
Category 5 UTP Using Repeaters
The LTC1686/LTC1687 can be used as repeaters to extend
the effective length of a high speed twisted-pair line. Figure
15a shows a three repeater configuration using 2000 feet
segments of category 5 UTP. Figure 15b shows the