AD8000

Data Sheet

Rev. C | Page 14 of 17

APPLICATIONS INFORMATION

All current feedback amplifier operational amplifiers are affected

by stray capacitance at the inverting input pin. As a practical

consideration, the higher the stray capacitance on the inverting

input to ground, the higher RF needs to be to minimize peaking

and ringing.

CIRCUIT CONFIGURATIONS

Figure 50 and Figure 51 show typical schematics for noninverting

and inverting configurations. For current feedback amplifiers,

the value of feedback resistance determines the stability and

bandwidth of the amplifier. The optimum performance values

are shown in Table 5 and should not be deviated from by more

than ±10% to ensure stable operation. Figure 8 shows the influence

varying RF has on bandwidth. In noninverting unity-gain

configurations, it is recommended that an RS of 50 Ω be used,

as shown in Figure 50.

Table 5 provides a quick reference for the circuit values, gain,

and output voltage noise.

FB

AD8000

10

F

0.1

F

RG

RS

+VS

VO

VIN

RL

–

+

VO

+V

–VS

–V

10

F

0.1

F

RF

+

+

NONINVERTING

Figure 50. Noninverting Configuration

FB

AD8000

10

F

0.1

F

RG

+VS

VO

VIN

RL

–

+

VO

+V

–VS

–V

10

F

0.1

F

RF

+

+

Figure 51. Inverting Configuration

VIDEO LINE DRIVER

The AD8000 is designed to offer outstanding performance as a

video line driver. The important specifications of differential

gain (0.02%), differential phase (0.01°), and 650 MHz bandwidth at

2 V p-p meet the most exacting video demands. Figure 52 shows a

typical noninverting video driver with a gain of +2.

432



432



75



CABLE

75



75



VOUT

+VS

–VS

VIN

0.1

F

4.7

F

AD8000

0.1

F

4.7

F

75



CABLE

75



+

+

+

FB

Figure 52. Video Line Driver

Table 5. Typical Values (LFCSP/SOIC)

Gain

Component

Values (Ω)

−3 dB SS Bandwidth

(MHz)

−3 dB LS Bandwidth

(MHz)

Slew Rate

(V/μs)

Output Noise

(nV/√Hz)

Total Output Noise Including

Resistors (nV/√Hz)

RF

RG

LFCSP

SOIC

LFCSP

SOIC

1

432

1380

1580

550

600

2200

10.9

11.2

2

432

432

600

650

610

650

3700

11.3

11.9

4

357

120

550

550

350

350

3800

10

12

10

357

40

350

365

370

370

3200

18.4

19.9