AD8029/AD8030/AD8040

Rev. A | Page 16 of 20

APPLICATIONS

WIDEBAND OPERATION

C2

10

µF

C1

0.1

µF

C4

0.1

µF

C3

10

µF

+

–

AD8029

R1

DISABLE

03679-0-052

Figure 51. Wideband Non-inverting Gain Configuration

C1

0.1

µF

C4

0.1

µF

C3

10

µF

R1

–

+

AD8029

03679-0-053

C2

10

µF

DISABLE

Figure 52. Wideband Inverting Gain Configuration

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

gains other than 1, in noninverting configurations, the feedback

network represents an additional current load at the amplifier

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.

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

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.

FREQUENCY (MHz)

0.01

–120

0.1

1.0

10

–40

–50

–60

–70

–80

–90

–100

–110

SECOND HARMONIC – SOLID LINES

THIRD HARMONIC – DOTTED LINES

Figure 53. Gain of 1 Distortion

FREQUENCY (MHz)

0.01

–120

0.1

1.0

10

–40

–50

–60

–70

–80

–90

–100

–110

SECOND HARMONIC – SOLID LINES

THIRD HARMONIC – DOTTED LINES

Figure 54. Gain of 2 Distortion