AD8061 Analog Devices, AD8061 Datasheet - Page 15

• Manufacturer Part Number: AD8061
• Description: Low Cost, 300 MHz Rail-to-Rail Amplifier (Single)
• Manufacturer: Analog Devices

Specifications of AD8061

• -3db Bandwidth: 320MHz
• Slew Rate: 650V/µs
• Vos: 1mV
• Ib: 350nA
• # Opamps Per Pkg: 1
• Input Noise (nv/rthz): 8.5nV/rtHz
• Vcc-vee: 2.7V to 8V
• Isy Per Amplifier: 9.5mA
• Packages: SOIC,SOT

As the saturation point of the output stage is approached, the
output signal shows increasing amounts of compression and
clipping. As in the input headroom case, the higher frequency
signals require a bit more headroom than lower frequency
signals. Figure 16, Figure 17, and Figure 18 illustrate this point,
plotting typical distortion vs. output amplitude and bias for
gains of 2 and 5.
OVERLOAD BEHAVIOR AND RECOVERY
Input
The specified input common-mode voltage of the AD8061/
AD8062/AD8063 is −200 mV below the negative supply to
within 1.8 V of the positive supply. Exceeding the top limit
results in lower bandwidth and increased settling time as seen
in Figure 46 and Figure 47. Pushing the input voltage of a unity-
gain follower beyond 1.6 V within the positive supply leads to
the behavior shown in Figure 48—an increasing amount of
output error and much increased settling time. Recovery time
from input voltages 1.6 V or closer to the positive supply is
approximately 35 ns, which is limited by the settling artifacts
caused by transistors in the input stage coming out of saturation.
The AD8061/AD8062/AD8063 family does not exhibit phase
reversal, even for input voltages beyond the voltage supply rails.
Going more than 0.6 V beyond the power supplies turns on
protection diodes at the input stage, which greatly increases the
current draw of the device.
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
0
Figure 47. Output Rising Edge for 1 V Step at
Input Headroom Limits, G = 1, V
4
8
12
2V TO 3V STEP
TIME (ns)
16
2.1V TO 3.1V STEP
2.2V TO 3.2V STEP
20
2.3V TO 3.3V STEP
S
= 5 V, 0 V
2.4V TO 3.4V STEP
24
28
32
Rev. G | Page 15 of 20
Output
Output overload recovery is typically within 40 ns after the
amplifier’s input is brought to a nonoverloading value. Figure 49
shows output recovery transients for the amplifier recovering
from a saturated output from the top and bottom supplies to a
point at midsupply.
–0.2
5.0
4.6
4.2
3.8
3.4
3.0
2.6
2.2
1.8
1.4
1.0
0.6
0.2
3.7
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
0
0
INPUT VOLTAGE
Figure 49. Overload Recovery, G = −1, V
Figure 48. Pulse Response for G = 1 Follower,
VOLTAGE STEP
FROM 2.4V TO 3.4V
Input Step Overloading the Input Stage
10
100
EDGES
VOLTAGE STEP
FROM 2.4V TO 3.6V
20
200
AD8061/AD8062/AD8063
30
VOLTAGE STEP
FROM 2.4V TO 3.8V,
4V AND 5V
TIME (ns)
TIME (ns)
300
40
V
–
IN
400
2.5V
50
OUTPUT VOLTAGE
5V TO 2.5V
R
OUTPUT VOLTAGE
0V TO 2.5V
S
500
= 5 V
60
R
5V
600
70
V
O
–