AD8040 Analog Devices, AD8040 Datasheet - Page 16

• Manufacturer Part Number: AD8040
• Description: Low-Power High-Speed Rail-to-Rail Input/Output Op Amplifier
• Manufacturer: Analog Devices

Specifications of AD8040

• Vcc-vee: 2.7V to 12V
• Isy Per Amplifier: 1.5mA
• Packages: SOIC,SOP
• -3db Bandwidth: 125MHz
• Slew Rate: 62V/µs
• Vos: 1.6mV
• Ib: 0.7µA
• # Opamps Per Pkg: 4
• Input Noise (nv/rthz): 16.5nV/rtHz

AD8029/AD8030/AD8040
APPLICATIONS
WIDEBAND OPERATION
OUTPUT LOADING SENSITIVITY
To achieve maximum performance and low power dissipation,
the designer needs to consider the loading at the output of
AD8029/AD8030/AD8040. Table 5 shows the effects of output
loading and performance.
When operating at unity gain, the effective load at the amplifier
output is the resistance (R
gains other than 1, in noninverting configurations, the feedback
network represents an additional current load at the amplifier
output. The feedback network (R
which lowers the effective resistance at the output of the
amplifier. The lower effective resistance causes the amplifier to
supply more current at the output. Lower values of feedback
resistance increase the current draw, thus increasing the
amplifier’s power dissipation.
Figure 51. Wideband Non-inverting Gain Configuration
Figure 52. Wideband Inverting Gain Configuration
V
IN
R1 = R
V
IN
R1 = R
R
F
G
R
||R
G
F
||R
R1
G
R1
G
L
–
AD8029
+
) being driven by the amplifier. For
–
AD8029
+
+V
–V
R
+V
–V
S
S
F
R
S
F
S
F
0.1µF
0.1µF
10µF
10µF
C2
C1
C4
C3
0.1µF
0.1µF
+ R
10µF
10µF
C2
C1
C4
C3
G
) is in parallel with R
DISABLE
DISABLE
03679-0-052
03679-0-053
V
OUT
V
OUT
L
Rev. A | Page 16 of 20
,
For example, if using the values shown in Table 5 for a gain of 2,
with resistor values of 2.5 kΩ, the effective load at the output is
1.67 kΩ. For inverting configurations, only the feedback resistor
R
that specified in the data sheet, the amplifier can introduce
nonlinearities in its open-loop response, which increases
distortion. Figure 53 and Figure 54 illustrate effective output
loading and distortion performance. Increasing the resistance of
the feedback network can reduce the current consumption, but
has other implications.
F
is in parallel with the output load. If the load is greater than
–100
–110
–120
–100
–110
–120
–40
–50
–60
–70
–80
–90
–40
–50
–60
–70
–80
–90
0.01
0.01
V
V
V
V
SECOND HARMONIC – SOLID LINES
THIRD HARMONIC – DOTTED LINES
V
V
V
V
SECOND HARMONIC – SOLID LINES
THIRD HARMONIC – DOTTED LINES
S
S
OUT
OUT
S
S
OUT
OUT
= 5V
= 5V
= 5V
= 5V
= 2.0V p-p
= 2.0V p-p
= 0.1V p-p
= 0.1V p-p
Figure 53. Gain of 1 Distortion
Figure 54. Gain of 2 Distortion
R
F
= R
0.1
0.1
FREQUENCY (MHz)
FREQUENCY (MHz)
L
R
= 1kΩ
L
= 1kΩ
R
F
= R
L
R
1.0
1.0
= 2.5kΩ
L
= 2.5kΩ
R
R
F
L
= R
= 5kΩ
L
= 5kΩ
10
10