ADA4860-1

Rev. 0 | Page 14 of 20

APPLICATION INFORMATION

POWER SUPPLY BYPASSING

Attention must be paid to bypassing the power supply pins of

the ADA4860-1. High quality capacitors with low equivalent

series resistance (ESR), such as multilayer ceramic capacitors

(MLCCs), should be used to minimize supply voltage ripple

and power dissipation. Generally, a 10 μF tantalum capacitor

located in close proximity to the ADA4860-1 is required to

provide good decoupling for lower frequency signals. In

addition, a 0.1 μF decoupling multilayer ceramic chip capacitor

(MLCC) should be located as close to each of the power supply

pins as is physically possible, no more than ⅛ inch away. The

ground returns should terminate immediately into the ground

plane. Locating the bypass capacitor return close to the load

return minimizes ground loops and improves performance.

FEEDBACK RESISTOR SELECTION

The feedback resistor has a direct impact on the closed-loop

bandwidth and stability of the current feedback op amp circuit.

Reducing the resistance below the recommended value can

make the amplifier response peak and even become unstable.

Increasing the size of the feedback resistor reduces the closed-

loop bandwidth. Table 5 provides a convenient reference for

quickly determining the feedback and gain set resistor values

and bandwidth for common gain configurations.

Table 5. Recommended Values and Frequency Performance1

Gain

−3 dB

SS BW

(MHz)

−3 dB

LS BW

(MHz)

Large

Signal

0.1 dB

Flatness

+1

550

N/A

800

165

40

−1

499

499

400

400

80

+2

499

499

520

230

125

+5

348

86.6

335

265

100

+10

348

38.3

165

195

28

Figure 51 and Figure 52 show the typical noninverting and

inverting configurations and the recommended bypass

capacitor values.

0.1µF

10µF

10µF

0.1µF

+

ADA4860-1

+

–

+

Figure 51. Noninverting Gain

0.1µF

10µF

10µF

0.1µF

ADA4860-1

+

–

+

+

Figure 52. Inverting Gain