LTC1687IS Linear Technology, LTC1687IS Datasheet - Page 10

• Manufacturer Part Number: LTC1687IS
• Description: IC TXRX RS485 PREC DELAY 14-SOIC
• Manufacturer: Linear Technology
• Type: Transceiverr

Specifications of LTC1687IS

• Number Of Drivers/receivers: 1/1
• Protocol: RS422, RS485
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
LTC1686/LTC1687
DC and AC attenuation over long distances. Figure 14a
shows a 1 s 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.
10
Figure 11b. 100 Feet of Category 5 UTP: 20ns Pulse
Figure 11a. 100 Feet of Category 5 UTP: 50Mbps
Figure 12. 1000 Feet of Category 5 UTP: 4Mbps
2V/DIV
2V/DIV
2V/DIV
2V/DIV
5V/DIV
2V/DIV
2V/DIV
U
CABLE DELAY
INFORMATION
100ns/DIV
U
10ns/DIV
20ns/DIV
W
1686/87 F11a
1686/87 F12
1685 F11b
RECEIVER
OUTPUT
DRIVER
INPUT
DRIVER
INPUT
RECEIVER
OUTPUT
DRIVER
INPUT
RECEIVER
INPUT
RECEIVER
OUTPUT
U
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
Figure 14b. 4000 Feet of Category 5 UTP 1Mbps Square Wave
Figure 13. 100 Feet of Telephone Grade UTP: 30Mbps
Figure 14a. 4000 Feet of Category 5 UTP 1 s Pulse
2V/DIV
1V/DIV
5V/DIV
2V/DIV
5V/DIV
2V/DIV
2V/DIV
2V/DIV
CABLE DELAY
20ns/DIV
1 s/DIV
1 s/DIV
1686/87 F13
1685 F14b
1685 F14a
DRIVER INPUT
DRIVER
INPUT
RECEIVER
OUTPUT
DIFFERENTIAL
RECEIVER
INPUT
RECEIVER
OUTPUT
DRIVER
INPUT
RECEIVER
INPUT
RECEIVER
OUTPUT