ADA4860-1

Rev. 0 | Page 15 of 20

DRIVING CAPACITIVE LOADS

If driving loads with a capacitive component is desired, the best

frequency response is obtained by the addition of a small series

resistance, as shown in Figure 53. Figure 54 shows the optimum

a 50 MHz, 50% duty cycle pulse, with an amplitude of 200 mV p-p.

approximately 1 dB of peaking in small signal frequency

response. It is worth noting that the frequency response of the

750Ω

ADA4860-1

Figure 53. Driving Capacitive Loads

14

12

10

8

6

4

2

0

050

40

30

20

10

CAPACITIVE LOAD (pF)

POWER DOWN PIN

The ADA4860-1 is equipped with a power-down function.

The POWER DOWN pin allows the user to reduce the quiescent

supply current when the amplifier is not being used. The

power-down threshold levels are derived from the voltage

this is especially useful with conventional logic levels. The

amplifier is powered down when the voltage applied to the

amplifier is enabled whenever the POWER DOWN pin is left

open, or the voltage on the POWER DOWN pin is less than

be connected to the negative supply.

VIDEO AMPLIFIER

With low differential gain and phase errors and wide 0.1 dB

flatness, the ADA4860-1 is an ideal solution for consumer and

professional video applications. Figure 55 shows a typical video

The video amplifier input is terminated into a shunt 75 Ω resistor.

At the output, the amplifier has a series 75 Ω resistor for

impedance matching to the video load.

75Ω

CABLE

75Ω

75Ω

0.1µF

0.1µF

10µF

10µF

75Ω

CABLE

75Ω

ADA4860-1

+

–

+

+

Figure 55. Video Driver Schematic

SINGLE-SUPPLY OPERATION

Single-supply operation can present certain challenges for the

designer. For a detailed explanation on op amp single-supply

operation, see Application Note AN-581.