Data Sheet

AD830

Rev. D | Page 17 of 20

75Ω

75Ω

AD830

1

2

3

4

8

7

6

5

A = 1

C

0.1µF

0.1µF

Figure 44. Full Bandwidth Line Driver (G = +2)

SUPPLY VOLTAGE (±V)

0.05

0.01

5

1

5

1

2

1

73

14

0.04

0.06

0.07

0.09

GAIN

PHASE

GAIN = +2

FREQ = 3.58MHz

0 TO 0.7V

11

10

9

8

6

0.02

0.03

0.10

0.08

0.16

0.04

0.06

0.14

0.18

0.02

0.12

0.10

0.08

0.20

Figure 45. Differential Gain and Phase for the Circuit of Figure 44

FREQUENCY (Hz)

0.2

10k

–0.8

100k

1M

10M

100M

–0.7

–0.6

–0.5

–0.4

–0.3

–0.2

–0.1

0

0.1

GAIN = +2

Figure 46. 0.1 dB Gain Flatness for the Circuit of Figure 44

AC-COUPLED LINE RECEIVER

The AD830 is configurable as an ac-coupled differential

amplifier on a single- or bipolar-supply voltage. All that is

needed is inclusion of a few noncritical passive components, as

input establishes a common-mode bias. Here, the common

mode is centered at 6 V, but in principle can be any voltage

within the common-mode limits of the AD830. The 10 kΩ

impedance to keep the input coupling corner frequency low, but

not too large so that residual bias current induced offset voltage

becomes troublesome. For dual-supply operation, the 10 kΩ

resistors may go directly to ground. The output common is

conveniently set by a Zener diode for a low impedance

reference to preserve the high frequency CMR. However, a

simple resistive divider works fine, and good high frequency

CMR can be maintained by placing a compensating resistor in

series with the +Y input. The excellent CMRR response of the

circuit is shown in Figure 48. A plot of the 0.1 dB flatness from

10 Hz is also shown. With the use of 10 μF capacitors, the CMR

is >90 dB down to a few tens of hertz. This level of performance

is almost impossible to achieve with discrete solutions.

75Ω

75Ω

+12V

1000µF

10µF

10µF

AD830

1

2

3

4

8

7

6

5

A = 1

C

0.1µF

75Ω

COAX

CABLE

+12V

4.7kΩ

6.8V

1N4736

INPUT

SIGNAL

10kΩ

10kΩ

2kΩ*

10kΩ

10kΩ

*OPTIONAL TUNING FOR IMPROVING

VERY LOW FREQUENCY CMR.

Figure 47. AC-Coupled Line Receiver