AD549
50
45
40
35
30
160
140
100k
10k
1k
WHENEVER JOHNSON NOISE IS GREATER THAN
AMPLIFIER NOISE, AMPLIFIER NOISE CAN BE
CONSIDERED NEGLIGIBLE FOR THE APPLICATION
1kHz BANDWIDTH
120
100
RESISTOR
JOHNSON NOISE
100
10
80
60
40
20
10Hz
BANDWIDTH
1
AMPLIFIER GENERATED NOISE
25
20
0.1
10
100
1k
10k
100k 1M
10M
100M
1G
10G 100G
0
5
10
15
20
SOURCE RESISTANCE – Ω
FREQUENCY – Hz
POWER SUPPLY VOLTAGE ± V
Figure 12. Noise vs. Source
Resistance
Figure 10. Input Bias Current
vs. Supply Voltage
Figure 11. Input Voltage Noise
Spectral Density
100
100
80
60
40
20
0
100
40
35
30
25
20
15
10
80
60
40
20
0
80
60
40
20
0
–20
–40
–20
–40
5
0
–20
10
100
1k
10k
100k
1M
10
100
1k
10k
100k 1M
10M
10
100
1k
10k
100k 1M
10M
FREQUENCY – Hz
FREQUENCY – Hz
FREQUENCY – Hz
Figure 13. Open-Loop
Frequency Response
Figure 14. Large Signal
Frequency Response
Figure 15. CMRR vs. Frequency
10
5
120
100
80
10mV
5mV
1mV
+ SUPPLY
60
0
–5
40
10mV
5mV
– SUPPLY
20
1mV
0
–20
–10
0
1
2
3
4
5
10
100
1k
10k
100k 1M
10M
SETTLING TIME – µs
FREQUENCY – Hz
Figure 16. PSRR vs. Frequency
Figure 17. Output Voltage
Swing and Error vs.
Settling Time
REV. A
–5–
ADI [ ADI ]
