AD8610/AD8620

Driving Large Capacitive Loads

+5V

The AD8610/AD8620 have excellent capacitive load driving

capability and can safely drive up to 10 nF when operating with

±5 V supply. Figure 44 and Figure 45 compare the AD8610/

AD8620 against the OPA627 in the noninverting gain configu­

2kΩ

2kΩ

–5V

2µF

3

2

7

4

ration driving a 10 kΩ resistor and 10,000 pF capacitor placed

Figure 46. Capacitive Load Drive Test Circuit

in parallel on its output, with a square wave input set to a frequency

of 200 kHz. The AD8610/AD8620 have much less ringing than

the OPA627 with heavy capacitive loads.

TIME (20µs/DIV)

TIME (2µs/DIV)

TIME (20µs/DIV)

TIME (2µs/DIV)

The AD8610/AD8620 can drive much larger capacitances

without any external compensation. Although the AD8610/

AD8620 are stable with very large capacitive loads, remember

that this capacitive loading limits the bandwidth of the amplifier.

Heavy capacitive loads also increase the amount of overshoot

and ringing at the output. Figure 47 and Figure 48 show the

AD8610/AD8620 and the OPA627 in a noninverting gain of +2

driving 2 μF of capacitance load. The ringing on the OPA627 is

much larger in magnitude and continues 10 times longer than

the AD8610/AD8620.

Rev. E | Page 14 of 24