AD645 AD [Analog Devices], AD645 Datasheet - Page 4

• Manufacturer Part Number: AD645
• Description: Low Noise, Low Drift FET Op Amp
• Manufacturer: AD [Analog Devices]

AD645–Typical Characteristics
Figure 7. Current Noise Spectral
Density vs. Frequency
Figure 10. Input Voltage Noise vs.
Source Resistance
Figure 13. Change in Input Offset
Voltage vs. Warmup Time
100
1.0
0.1
100
10
1.0
1k
10
–
–
1
10
50
25
25
50
0
3
0
NOISE BANDWIDTH: 0.1 to 10Hz
10
10
4
1
SOURCE RESISTANCE –
WARM-UP TIME – Minutes
100
10
FREQUENCY – Hz
5
2
10
1k
6
3
T = +25 C
V = 15V
A
S
10
10k
7
4
10
100k
8
5
10
1M
9
Figure 8. Voltage Noise Spectral
Density vs. Frequency
Figure 11. Voltage and Current
Noise Spectral Density vs.
Temperature
Figure 14. Change in Input Offset
Voltage vs. Time from Thermal
Shock
100
25
20
15
10
10
1k
5
–
0
60
1
–
(@ +25 C,
150
–
150
75
75
0
–
40
0
f = 1kHz
o
–
20
10
TIME FROM THERMAL SHOCK – Minutes
CURRENT NOISE
1
0
TEMPERATURE – C
FREQUENCY – Hz
20
15 V unless otherwise noted)
T
100
A
–4–
= 25 C TO T
2
VOLTAGE NOISE
40
60
1k
3
A
80
= 85 C
100 120 140
10k
4
100
10
1
0.1
0.01
5
100k
Figure 9. Voltage Noise Spectral
Density vs. Frequency for Various
Source Resistances
Figure 12. Voltage Noise Spectral
Density @ 1 kHz vs. Source
Resistance
Figure 15. Input Bias and Offset
Currents vs. Temperature
1000
10
10
10
10
10
100
10
100
1.0
10
1k
10
–
–
–
–
–
–
10
12
13
14
100
11
–
1
9
0.1
60
NOISE OF AD645
AND RESISTOR
–
40
RESISTOR NOISE
ONLY
1k
–
1.0
20
SOURCE RESISTANCE –
0
10k
TEMPERATURE – C
10
CURRENT
FREQUENCY – Hz
20
INPUT
BIAS
40
100k
100
60
CURRENT
OFFSET
INPUT
80 100 120 140
SOURCE
RESISTANCE
1M
1k
R = 10M
R = 1M
R = 100k
R = 100
S
S
S
S
10M
10k
REV. B
10
10
10
10
10
10
100M
–
–
–
–
–
–
100k
10
11
12
14
9
13