AD8610ARM Analog Devices, AD8610ARM Datasheet - Page 10

• Manufacturer Part Number: AD8610ARM
• Description: Precision Very Low Noise Low Input Bias Current Wide Bandwith JFET Operational Amplifier
• Manufacturer: Analog Devices

AD8610
Driving Large Capacitive Loads
The AD8610 has excellent capacitive load driving capability and
can safely drive up to 10 nF when operating with ± 5 V supply.
Figures 2 and 3 compare the AD8610 against the OPA627 in the
noninverting gain configuration driving a 10 kΩ resistor and
10,000 pF capacitor placed in parallel on its output, with a square
wave input set to a frequency of 200 kHz. The AD8610 has much
less ringing than the OPA627 with heavy capacitive loads.
The AD8610 can drive much larger capacitances without any
external compensation. Although the AD8610 is stable with very
large capacitive loads, remember that this capacitive loading will
limit the bandwidth of the amplifier. Heavy capacitive loads will also
increase the amount of overshoot and ringing at the output. Figures
5 and 6 show the AD8610 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 more than 10 times longer
than the AD8610.
V
R
C
V
R
C
S
L
L
S
L
L
=
= 10k
= 10,000pF
=
= 10k
= 10,000pF
V
5V
5V
IN
= 50mV
2k
3
2
TIME – 2 s/DIV
TIME – 2 s/DIV
+5V
–5V
2k
7
4
2 F
Slew Rate (Unity Gain Inverting vs. Noninverting)
Amplifiers generally have a faster slew rate in an inverting unity
gain configuration due to the absence of the differential input
capacitance. Figures 7 through 10 show the performance of the
AD8610 configured in a gain of –1 compared to the OPA627.
The AD8610 slew rate is more symmetrical, and both the positive
and negative transitions are much cleaner than in the OPA627.
V
R
C
TIME – 400ns/DIV
V
R
C
TIME – 20 s/DIV
TIME – 20 s/DIV
S
L
L
S
L
L
=
= 10k
= 2 F
=
= 10k
= 2 F
SR = 54V/ s
5V
5V
V
R
G = –1
S
L
=
= 2k
13V