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 R
F
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 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
10F
0.1F
R
G
R
S
+V
S
V
O
V
IN
R
L
–
+
V
O
+V
–V
S
–V
10F
0.1F
R
F
+
+
NONINVERTING
05321-035
Figure 50. Noninverting Configuration
FB
AD8000
10F
0.1F
R
G
+V
S
V
O
IN
R
L
–
+
V
O
+V
–V
S
–V
10F
0.1F
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 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
V
OUT
+V
S
–V
S
IN
0.1F
4.7F
AD8000
0.1F
4.7F
75
CABLE
75
+
+
+
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/μs)
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
