Datasheet
AD8000 Data Sheet
Rev. B | Page 14 of 20
APPLICATIONS
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 R
F
needs to be to
minimize peaking and ringing.
CIRCUIT CONFIGURATIONS
Figure 50 and Figure 51 show typical schematics for non-
inverting 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 R
F
has on bandwidth. In
noninverting unity-gain configurations, it is recommended that
an R
S
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
10µF
0.1µF
R
G
R
S
+V
S
V
O
V
IN
R
L
–
+
V
O
+V
–
V
S
–V
10
µF
0.1
µF
R
F
+
+
NONINVERTING
05321-035
Figure 50. Noninverting Configuration
FB
AD8000
10µF
0.1µF
R
G
+V
S
V
O
V
IN
R
L
–
+
V
O
+V
–V
S
–V
10µF
0.1µF
R
F
+
+
05321-036
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 band-
width at 2 V p-p meet the most exacting video demands. Figure 52
shows a typical noninverting video driver with a gain of +2.
432Ω
432Ω
75Ω
CABLE
75Ω
75Ω
V
OUT
+V
S
–V
S
V
IN
0.1µF
4.7µF
AD8000
0.1µF
4.7µF
75Ω
CABLE
75Ω
+
+
+
05321-071
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/µsec)
Output Noise
(nV/√Hz)
Total Output
Noise Including
Resistors (nV/√Hz)
R
F
R
G
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