Datasheet

Time (ns)
Voltage (V)
0 50 100 150 200 250 300 350 400 450 500
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
D001
Unbuffered
SN74HCT245
11
SN54HCT245 , SN74HCT245
www.ti.com SCLS020F –MARCH 1984–REVISED AUGUST 2016
Product Folder Links: SN54HCT245 SN74HCT245
Submit Documentation FeedbackCopyright © 1984–2016, Texas Instruments Incorporated
Typical Application (continued)
9.2.3 Application Curve
It is common to see significant losses in ribbon cables and back planes. The plot shown in Figure 5 is a
simplified simulation of a ribbon cable from a 5-V, 10-MHz low drive strength source. It shows the difference
between an input signal from a weak driver like an MCU or FPGA compared to a strong driver like the
SN74HCT245 when measured at the distant end of the cable. By adding a high-current drive transceiver before
the cable, the signal strength can be significantly improved, and subsequently the cable can be longer.
Unbuffered line is directly connected to low current source, SN74HCT245 line is buffered through the
transceiver. Both signals are measured at the distant end of the ribbon cable.
Figure 5. Simulated Outputs From Ribbon Cable With a 5-V, 10-MHz Source