HD26LS31

Rev.2.00, Jul.16.2004, page 10 of 11

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

inverter transistor (Q

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

within which the output current limiter circuit operates will be entered, as can be seen from the I

characteristics shown in figure 3. In this region, the output stage power dissipation is 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.

5

2

1.0

0.5

0.2

0.1

0.05

10

20

50

100 200

500 1 k

2 k

5 k 10 k 20 k

50 k

Ta = 25°C

Z

"H"

GND

Y

Figure 8 Termination Resistance vs. Output Voltage Characteristics

Z

Y

Data input

Figure 9 Example of Driver Use-3

5

2

1.0

0.5

0.2

0.1

0.05

10

20

50

100 200

500 1 k

2 k

5 k 10 k 20 k

50 k

Ta = 25°C

Z

"L"

GND

Y

Figure 10 Termination Resistance vs. Output Voltage Characteristic