HD26LS31 Renesas, HD26LS31 Datasheet - Page 14

• Manufacturer Part Number: HD26LS31
• Manufacturer: Renesas

HD26LS31
A feature of termination implemented as shown in figure 9 is that power dissipation is low when the duty of
the transmitted signal is high.
However, care is required, since if R
since the inverter transistor (Q
the output low level will rise.
Figure 10 shows the output voltage characteristics when termination resistance R
With the method of using the driver described above, if termination resistance R
small, the region within which the output current limiter circuit operates will be entered, as can be seen
from the I
large and the output voltage changes abruptly. A measure such as insertion of a capacitor in series with the
termination resistance is therefore necessary. Consequently, when selecting the transmission line, the
circuit termination resistance to be used requires careful consideration.
12
0.05
1.0
0.5
0.2
0.1
5
2
10
OH
vs. V
20
Figure 8 Termination Resistance vs. Output Voltage Characteristics
OH
50 100 200
characteristics shown in figure 3. In this region, the output stage power dissipation is
Termination Resistance R
4
in figure 2) has no protection circuit, and so a large current will flow and
500 1 k 2 k
Figure 9 Example of Driver Use-3
Data input
T
is sufficiently small, when the output on the pulled-up side goes low,
V
OH (Y)
V
OL (Z)
T
( )
5 k 10 k 20 k
Y
Z
R
R
T
T
50 k
V
CC
"H"
Y
Z
T
is varied.
T
becomes sufficiently
R
T
GND
V
Ta = 25 C
CC
= 5 V
V
OL
V
OH