AD841

Data Sheet

Rev. C | Page 12 of 16

TERMINATED LINE DRIVER

The AD841 functions very well as a high speed line driver of

either terminated or unterminated cables. Figure 33 shows the

AD841 driving a doubly terminated cable in a follower config-

uration. The AD841 maintains a typical slew rate of 300 V/µs,

which means it can drive a ±10 V, 4.7 MHz signal or a ±3 V,

15.9 MHz signal.

impedance of the cable) minimizes reflections from the far end

characteristic impedance of the cable) may be placed between

the AD841 output and the cable to damp any stray signals

impedance. This results in a cleaner signal, but because half the

double the output signal required if there is no back termina-

tion. Therefore, the full power bandwidth is cut in half.

If termination is not used, cables appear as capacitive loads. If

this capacitive load is large, it should be decoupled from the

AD841 by a resistor in series with the output (see Figure 32).

Figure 33. Line Driver Configuration

OVERDRIVE RECOVERY

Figure 34 shows the overdrive recovery capability of the AD841.

Typical recovery time is 200 ns from negative overdrive and

700 ns from positive overdrive.

Figure 34. Overdrive Recovery

Figure 35. Overdrive Recovery Test Circuit

11

6

4

5

10

–

+

AD841

2.2µF

0.1µF

2.2µF

0.1µF

TERMINATION

RESISTOR

FOR INPUT

SIGNAL

100Ω

(OPTIONAL)

50Ω OR

75Ω CABLE

100

90

10

0%

10V

200ns

1V

OVERDRIVEN

OUTPUT: 10V/DIV

INPUT SQUARE

WAVE: 1V/DIV

11

6

4

5

10

–

+

AD841

2.2µF

0.1µF

2.2µF

0.1µF

OUTPUT

1kΩ

50Ω

HP3314A

PULSE GENERATOR

OR EQUIVALENT

1µs ± 1V SQUARE

WAVE INPUT