AD AD8622ARMZ-R7 Dual, low power, precision rail-to-rail output op amp Datasheet

Dual, Low Power, Precision
Rail-to-Rail Output Op Amp
AD8622
PIN CONFIGURATIONS
Very low offset voltage
125 μV maximum
Supply current: 215 μA/amp typical
Input bias current: 200 pA maximum
Low input offset voltage drift: 1.2 μV/°C maximum
Very low voltage noise: 11 nV/√Hz
Operating temperature: −40°C to +125°C
Rail-to-rail output swing
Unity gain stable
±2.5 V to ±15 V operation
OUT A 1
–IN A 2
AD8622
+IN A 3
TOP VIEW
V– 4 (Not to Scale)
8
V+
7
OUT B
6
–IN B
5
+IN B
07527-001
FEATURES
OUT A 1
–IN A 2
+IN A 3
8
AD8622
V+
7
TOP VIEW
(Not to Scale)
OUT B
6
–IN B
5
+IN B
V– 4
07527-002
Figure 1. 8-Lead Narrow-Body SOIC
Figure 2. 8-Lead MSOP
APPLICATIONS
Portable precision instrumentation
Laser diode control loops
Strain gage amplifiers
Medical instrumentation
Thermocouple amplifiers
GENERAL DESCRIPTION
Table 1. Low Power Op Amps
The AD8622 is a dual, precision rail-to-rail output operational
amplifier with a low supply current of only 350 μA maximum
over temperature and supply voltages. It also offers ultralow
offset, drift, and voltage noise combined with very low input
bias current over the full operating temperature range.
Supply
40 V
36 V
12 V to 16 V
5V
Single
OP97
OP297
OP196
AD8663
OP296
AD8667
AD8603
Dual
Quad
OP497
OP777
OP1177
OP727
OP2177
AD706
OP747
OP4177
AD704
OP496
AD8669
AD8609
With typical offset voltage of only 10 μV, offset drift of 0.5 μV/°C,
and noise of only 0.2 μV p-p (0.1 Hz to 10 Hz), it is perfectly
suited for applications where large error sources cannot be
tolerated. Many systems can take advantage of the low noise,
dc precision, and rail-to-rail output swing provided by the
AD8622 to maximize the signal-to-noise ratio and dynamic
range for low power operation. The AD8622 is specified for the
extended industrial temperature range of −40°C to +125°C and
is available in lead-free SOIC and MSOP packages.
AD8607
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.
AD8622
TABLE OF CONTENTS
Features .............................................................................................. 1
ESD Caution...................................................................................5
Applications ....................................................................................... 1
Typical Performance Characteristics ..............................................6
Pin Configurations ........................................................................... 1
Applications Information .............................................................. 15
General Description ......................................................................... 1
Input Protection ......................................................................... 15
Revision History ............................................................................... 2
Phase Reversal ............................................................................ 15
Specifications..................................................................................... 3
Micropower Instrumentation Amplifier ................................. 15
Electrical Characteristics—±15 V Operation ........................... 3
Hall Sensor Signal Conditioning .............................................. 16
Electrical Characteristics—±2.5 V Operation .......................... 4
Simplified Schematic ...................................................................... 17
Absolute Maximum Ratings............................................................ 5
Outline Dimensions ....................................................................... 18
Thermal Resistance ...................................................................... 5
Ordering Guide .......................................................................... 18
REVISION HISTORY
7/09—Revision 0: Initial Version
Rev. 0 | Page 2 of 20
AD8622
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS—±15 V OPERATION
VS = ±15 V, VCM = 0 V, TA = +25°C, unless otherwise specified.
Table 2.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Symbol
Conditions
Min
VOS
Offset Voltage Drift
Input Bias Current
ΔVOS/ΔT
IB
Input Offset Current
IOS
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
Typ
Max
Unit
10
125
230
1.2
200
500
200
500
+13.8
μV
μV
μV/°C
pA
pA
pA
pA
V
dB
dB
dB
dB
GΩ
TΩ
pF
pF
0.5
45
−40°C ≤ TA ≤ +125°C
35
−40°C ≤ TA ≤ +125°C
Input Voltage Range
Common-Mode Rejection Ratio
CMRR
Open-Loop Gain
AVO
Input Resistance, Differential Mode
Input Resistance, Common Mode
Input Capacitance, Differential Mode
Input Capacitance, Common Mode
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Short-Circuit Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Uncorrelated Current Noise Density
Correlated Current Noise Density
VCM = −13.8 V to +13.8 V
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ, VO = −13.5 V to +13.5 V
−40°C ≤ TA ≤ +125°C
−13.8
125
112
125
120
RINDM
RINCM
CINDM
CINCM
VOH
VOL
ISC
ZOUT
PSRR
ISY
135
137
1
1
5.5
3
RL = 100 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 100 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ to ground
−40°C ≤ TA ≤ +125°C
14.94
14.84
14.86
14.75
14.89
−14.97
−14.89
−14.94
−14.92
−14.90
−14.80
±40
1.5
f = 1 kHz, AV = 1
VS = ±2.0 V to ±18.0 V
−40°C ≤ TA ≤ +125°C
IO = 0 mA
−40°C ≤ TA ≤ +125°C
14.97
125
120
145
215
250
350
V
V
V
V
V
V
V
V
mA
Ω
dB
dB
μA
μA
SR
GBP
ΦM
RL = 10 kΩ, AV = 1
CL = 35 pF, AV = 1
CL = 35 pF, AV = 1
0.48
600
72
V/μs
kHz
Degrees
en p-p
en
in
in
f = 0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f = 1 kHz
0.2
11
0.15
0.06
μV p-p
nV/√Hz
pA/√Hz
pA/√Hz
Rev. 0 | Page 3 of 20
AD8622
ELECTRICAL CHARACTERISTICS—±2.5 V OPERATION
VS = ±2.5 V, VCM = 0 V, TA = +25°C, unless otherwise specified.
Table 3.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Symbol
Conditions
Min
VOS
Offset Voltage Drift
Input Bias Current
ΔVOS/ΔT
IB
Input Offset Current
IOS
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
Typ
Max
Unit
10
125
230
1.2
200
400
200
300
+1.3
μV
μV
μV/°C
pA
pA
pA
pA
V
dB
dB
dB
dB
GΩ
TΩ
pF
pF
0.5
30
−40°C ≤ TA ≤ +125°C
Input Voltage Range
Common-Mode Rejection Ratio
CMRR
Open-Loop Gain
AVO
Input Resistance, Differential Mode
Input Resistance, Common Mode
Input Capacitance, Differential Mode
Input Capacitance, Common Mode
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Short-Circuit Current
Closed-Loop Output Impedance
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current/Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Gain Bandwidth Product
Phase Margin
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Uncorrelated Current Noise Density
Correlated Current Noise Density
25
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
VCM = −1.3 V to +1.3 V
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ, VO = −2.0 V to +2.0 V
−40°C ≤ TA ≤ +125°C
−1.3
110
107
118
109
RINDM
RINDM
CINDM
CINCM
VOH
VOL
ISC
ZOUT
PSRR
ISY
120
135
1
1
5.5
3
RL = 100 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 100 kΩ to ground
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ to ground
−40°C ≤ TA ≤ +125°C
2.45
2.41
2.40
2.36
2.45
−2.49
−2.45
−2.45
−2.41
−2.40
−2.36
±30
2
f = 1 kHz, AV = 1
VS = ±2.0 V to ±18.0 V
−40°C ≤ TA ≤ +125°C
IO = 0 mA
−40°C ≤ TA ≤ +125°C
2.49
125
120
145
175
225
310
V
V
V
V
V
V
V
V
mA
Ω
dB
dB
μA
μA
SR
GBP
ΦM
RL = 10 kΩ, AV = 1
CL = 35 pF, AV = 1
CL = 35 pF, AV = 1
0.28
580
72
V/μs
kHz
Degrees
en p-p
en
in
in
f = 0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz
f = 1 kHz
0.2
12
0.15
0.07
μV p-p
nV/√Hz
pA/√Hz
pA/√Hz
Rev. 0 | Page 4 of 20
AD8622
ABSOLUTE MAXIMUM RATINGS
Table 4.
Parameter
Supply Voltage
Input Voltage
Input Current1
Differential Input Voltage2
Output Short-Circuit Duration to GND
Storage Temperature Range
Operating Temperature Range
Junction Temperature Range
Lead Temperature (Soldering, 60 sec)
Rating
± 18 V
±V supply
±10 mA
±10 V
Indefinite
−65°C to +150°C
−40°C to +125°C
−65°C to +150°C
300°C
1
The input pins have clamp diodes to the power supply pins. The input
current should be limited to 10 mA or less whenever input signals exceed
the power supply rail by 0.5 V.
2
Differential input voltage is limited to 10 V or the supply voltage, whichever is less.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages. This
was measured using a standard 4-layer board.
Table 5. Thermal Resistance
Package Type
8-Lead SOIC_N (R-8)
8-Lead MSOP (RM-8)
ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Rev. 0 | Page 5 of 20
θJA
158
185
θJC
43
53
Unit
°C/W
°C/W
AD8622
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, unless otherwise noted.
60
60
VSY = ±15V
VCM = 0V
VSY = ±2.5V
VCM = 0V
50
NUMBER OF AMPLIFIERS
40
30
20
40
30
20
–60
–40
–20
0
20
VOS (µV)
40
60
80
0
–100 –80
07527-063
0
–100 –80
100
Figure 3. Input Offset Voltage Distribution
–60
–40
–20
0
20
VOS (µV)
80
100
60
VSY = ±15V
–40°C ≤ TA ≤ +125°C
VSY = ±2.5V
–40°C ≤ TA ≤ +125°C
50
NUMBER OF AMPLIFIERS
50
NUMBER OF AMPLIFIERS
60
Figure 6. Input Offset Voltage Distribution
60
40
30
20
40
30
20
10
10
0
0.2
0.4
0.6
0.8
TCVOS (µV/°C)
1.0
1.2
0
07527-064
0
40
07527-065
10
10
0
0.2
Figure 4. Input Offset Voltage Drift Distribution
0.4
0.6
0.8
TCVOS (µV/°C)
1.0
1.2
07527-066
NUMBER OF AMPLIFIERS
50
Figure 7. Input Offset Voltage Drift Distribution
50
50
VSY = ±15V
40
40
30
VSY = ±2.5V
–40°C
30
20
20
+25°C
–10
10
+25°C
0
–10
+85°C
+85°C
–20
–20
+125°C
–30
–30
–40
–40
–50
0
5
10
15
VCM (V)
20
25
30
–50
–2.5
+125°C
–1.5
–0.5
0.5
1.5
VCM (V)
Figure 5. Input Offset Voltage vs. Common-Mode Voltage
Figure 8. Input Offset Voltage vs. Common-Mode Voltage
Rev. 0 | Page 6 of 20
2.5
07527-007
VOS (µV)
0
07527-004
VOS (µV)
–40°C
10
AD8622
40
40
VSY = ±15V
VSY = ±2.5V
IB+
30
20
20
0
0
IB (pA)
IB (pA)
10
IB–
IB+
–20
–10
IB–
–40
–20
–25
0
25
50
75
100
125
TEMPERATURE (°C)
–80
–50
07527-008
–40
–50
–25
0
25
50
75
100
125
TEMPERATURE (°C)
Figure 9. Input Bias Current vs. Temperature
07527-011
–60
–30
Figure 12. Input Bias Current vs. Temperature
60
50
VSY = ±15V
VSY = ±2.5V
25
40
0
–25
IB (pA)
IB (pA)
20
0
–50
–75
–20
–100
–40
5
10
15
20
25
30
VCM (V)
–150
1
2
3
4
5
VCM (V)
Figure 10. Input Bias Current vs. Common-Mode Voltage
Figure 13. Input Bias Current vs. Common-Mode Voltage
100k
100k
10k
1k
VCC – VOH
100
VOL – VEE
10
1
0.001
0.01
0.1
1
LOAD CURRENT (mA)
10
100
VSY = ±2.5V
10k
1k
VCC – VOH
100
10
1
0.001
Figure 11. Output Voltage to Supply Rail vs. Load Current
VOL – VEE
0.01
0.1
1
LOAD CURRENT (mA)
10
Figure 14. Output Voltage to Supply Rail vs. Load Current
Rev. 0 | Page 7 of 20
100
07527-013
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
VSY = ±15V
07527-010
OUTPUT VOLTAGE TO SUPPLY RAIL (mV)
0
07527-012
0
07527-009
–60
–125
AD8622
0.06
VCC – VOH
0.10
0.08
0.06
VOL – VEE
0.04
0.02
–25
0
25
50
TEMPERATURE (°C)
75
100
125
VCC – VOH
0.04
0.03
0.02
VOL – VEE
0.01
0
–50
07527-014
Figure 15. Output Voltage to Supply Rail vs. Temperature
25
50
TEMPERATURE (°C)
75
100
125
100
100
80
80
60
60
60
60
40
40
40
40
GAIN
20
20
0
GAIN (dB)
VSY = ±15V
RL = 10kΩ
PHASE
80
100k
FREQUENCY (Hz)
–40
10M
1M
GAIN
0
–20
–40
1k
Figure 16. Open-Loop Gain and Phase vs. Frequency
AV = 100
40
AV = 100
30
GAIN (dB)
AV = 10
AV = 1
0
20
10
–10
–20
–20
–30
–30
10k
100k
FREQUENCY (Hz)
1M
10M
–40
100
07527-016
1k
Figure 17. Closed-Loop Gain vs. Frequency
AV = 10
AV = 1
0
–10
–40
100
–40
10M
1M
VSY = ±2.5V
RL = 10kΩ
50
30
10
100k
FREQUENCY (Hz)
60
VSY = ±15V
RL = 10kΩ
50
20
10k
Figure 19. Open-Loop Gain and Phase vs. Frequency
60
40
20
–20
07527-015
10k
80
PHASE
0
–20
–40
1k
100
VSY = ±2.5V
RL = 10kΩ
20
0
–20
GAIN (dB)
GAIN (dB)
0
Figure 18. Output Voltage to Supply Rail vs. Temperature
PHASE (Degrees)
100
–25
1k
10k
100k
FREQUENCY (Hz)
1M
Figure 20. Closed-Loop Gain vs. Frequency
Rev. 0 | Page 8 of 20
10M
07527-019
0
–50
0.05
PHASE (Degrees)
0.12
VSY = ±2.5V
RL = 10kΩ
07527-018
0.14
07527-017
VSY = ±15V
RL = 10kΩ
OUTPUT VOLTAGE TO SUPPLY RAIL (V)
OUTPUT VOLTAGE TO SUPPLY RAIL (V)
0.16
AD8622
10k
10k
VSY = ±15V
AV = 10
AV = 10
100
AV = 1
10
100
10
1
10k
FREQUENCY (Hz)
100k
1M
0.1
100
Figure 21. Output Impedance vs. Frequency
120
80
80
CMRR (dB)
100
60
40
20
20
0
10
07527-021
1M
Figure 22. CMRR vs. Frequency
120
VSY = ±2.5V
100
120
VSY = ±15V
100k
1M
VSY = ±2.5V
100
PSRR+
PSRR+
80
60
PSRR–
60
40
40
20
20
1k
10k
FREQUENCY (Hz)
100k
1M
0
10
07527-022
100
Figure 23. PSRR vs. Frequency
PSRR–
100
1k
10k
FREQUENCY (Hz)
Figure 26. PSRR vs. Frequency
Rev. 0 | Page 9 of 20
100k
1M
07527-025
PSRR (dB)
80
PSRR (dB)
1k
10k
FREQUENCY (Hz)
Figure 25. CMRR vs. Frequency
100
0
10
1M
60
40
100k
100k
120
100
1k
10k
FREQUENCY (Hz)
10k
FREQUENCY (Hz)
Figure 24. Output Impedance vs. Frequency
VSY = ±15V
100
1k
07527-024
1k
07527-020
0.1
100
CMRR (dB)
AV = 1
07527-023
1
0
10
AV = 100
1k
AV = 100
ZOUT (Ω)
ZOUT (Ω)
1k
VSY = ±2.5V
AD8622
50
50
40
35
OS–
25
OS+
20
OS–
30
20
15
15
10
10
5
5
0.1
1
CAPACITANCE (nF)
10
100
0
0.01
07527-026
0
0.01
OS+
25
Figure 27. Small-Signal Overshoot vs. Load Capacitance
0.1
1
CAPACITANCE (nF)
10
100
Figure 30. Small-Signal Overshoot vs. Load Capacitance
VSY = ±2.5V
AV = 1
RL = 10kΩ
CL = 100pF
TIME (40µs/DIV)
07527-027
VOLTAGE (5V/DIV)
VOLTAGE (500mV/DIV)
VSY = ±15V
AV = 1
RL = 10kΩ
CL = 100pF
TIME (40µs/DIV)
Figure 28. Large-Signal Transient Response
Figure 31. Large-Signal Transient Response
TIME (10µs/DIV)
07527-028
VOLTAGE (50mV/DIV)
VSY = ±2.5V
AV = 1
RL = 10kΩ
CL = 100pF
VOLTAGE (50mV/DIV)
VSY = ±15V
AV = 1
RL = 10kΩ
CL = 100pF
TIME (10µs/DIV)
Figure 29. Small-Signal Transient Response
Figure 32. Small-Signal Transient Response
Rev. 0 | Page 10 of 20
07527-029
30
OVERSHOOT (%)
35
OVERSHOOT (%)
VSY = ±2.5V
AV = 1
RL = 10kΩ
07527-030
40
45
07527-031
45
VSY = ±15V
AV = 1
RL = 10kΩ
AD8622
0.4
INPUT
INPUT
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
0
OUTPUT
0
0
OUTPUT
0
–1
–20
–2
07527-032
–10
TIME (20µs/DIV)
–3
TIME (20µs/DIV)
Figure 33. Negative Overload Recovery
Figure 36. Negative Overload Recovery
0.2
OUTPUT VOLTAGE (V)
–0.2
INPUT VOLTAGE (V)
INPUT
0
20
10
OUTPUT
–0.2
INPUT VOLTAGE (V)
0
3
2
OUTPUT
0
VSY = ±15V
AV = –100
RL = 10kΩ
07527-033
–20
TIME (20µs/DIV)
0
–1
TIME (20µs/DIV)
Figure 34. Positive Overload Recovery
Figure 37. Positive Overload Recovery
12
12
VSY = ±15V
AV = –1
VSY = ±15V
AV = +1
10
8
8
0.1%
OUTPUT STEP (V)
10
0.01%
6
4
0.1%
0.01%
6
4
2
5
10
15
20
25
SETTLING TIME (µs)
30
35
0
07527-034
0
Figure 35. Output Step vs. Settling Time
0
5
10
15
20
25
SETTLING TIME (µs)
Figure 38. Output Step vs. Settling Time
Rev. 0 | Page 11 of 20
30
35
07527-037
2
0
1
VSY = ±2.5V
AV = –100
RL = 10kΩ
–10
OUTPUT VOLTAGE (V)
INPUT
07527-036
0.2
OUTPUT STEP (V)
VSY = ±2.5V
AV = –100
RL = 10kΩ
0.2
INPUT VOLTAGE (V)
0.2
OUTPUT VOLTAGE (V)
VSY = ±15V
AV = –100
RL = 10kΩ
07527-035
0.4
AD8622
100
100
VSY = ±2.5V
10
100
1k
FREQUENCY (Hz)
1
1
CURRENT NOISE DENSITY (pA/ Hz)
UNCORRELATED
RS1 = 0Ω
CORRELATED
RS1 = RS2
1
10
100
1k
FREQUENCY (Hz)
VSY = ±2.5V
RS2
UNCORRELATED
RS1 = 0Ω
CORRELATED
RS1 = RS2
0.1
0.01
07527-056
CURRENT NOISE DENSITY (pA/ Hz)
RS2
0.01
RS1
VSY = ±15V
0.1
1k
Figure 42. Voltage Noise Density vs. Frequency
1
RS1
100
FREQUENCY (Hz)
Figure 39. Voltage Noise Density vs. Frequency
1
10
1
10
1k
100
FREQUENCY (Hz)
Figure 40. Current Noise Density vs. Frequency
Figure 43. Current Noise Density vs. Frequency
VSY = ±15V
TIME (1s/DIV)
07527-040
INPUT NOISE VOLTAGE (50nV/DIV)
INPUT NOISE VOLTAGE (50nV/DIV)
VSY = ±2.5V
TIME (1s/DIV)
Figure 41. 0.1 Hz to 10 Hz Noise
Figure 44. 0.1 Hz to 10 Hz Noise
Rev. 0 | Page 12 of 20
07527-057
1
07527-043
1
10
07527-042
VOLTAGE NOISE DENSITY (nV/ Hz)
10
07527-039
VOLTAGE NOISE DENSITY (nV Hz)
VSY = ±15V
AD8622
0.35
0.35
0.30
+125°C
0.30
+85°C
0.25
0.25
+25°C
ISY (mA)
ISY (mA)
0.20
0.15
–40°C
0.10
VSY = ±15V
0.20
VSY = ±2.5V
0.15
0.05
0
2
4
6
8
10
VSY (±V)
12
14
16
18
0.05
–50
07527-044
–25
Figure 45. Supply Current vs. Supply Voltage
0
25
50
75
TEMPERATURE (°C)
100
Figure 48. Supply Current vs. Temperature
1
1
VSY = ±2.5V
f = 1kHz
RL = 10kΩ
VSY = ±15V
f = 1kHz
RL = 10kΩ
0.1
THD + N (%)
0.01
0.01
0.001
0.001
0.01
0.1
AMPLITUDE (V rms)
1
10
0.0001
0.001
07527-046
0.0001
0.001
0.01
0.1
AMPLITUDE (V rms)
1
10
Figure 49. THD + Noise vs. Amplitude
Figure 46. THD + Noise vs. Amplitude
0.1
VSY = ±15V
RL = 10kΩ
VIN = 300mV rms
VSY = ±2.5V
RL = 10kΩ
VIN = 300mV rms
0.01
THD + N (%)
THD + N (%)
0.01
0.001
100
1k
FREQUENCY (Hz)
10k
100k
07527-050
0.0001
10
0.001
Figure 47. THD + Noise vs. Frequency
0.0001
10
100
1k
FREQUENCY (Hz)
10k
Figure 50. THD + Noise vs. Frequency
Rev. 0 | Page 13 of 20
100k
07527-051
THD + N (%)
0.1
0.1
125
07527-049
–0.05
07527-045
0.10
0
AD8622
0
100kΩ
1kΩ
RL
–40
–60
–80
–100
–120
–140
10
VSY = ±2.5V TO ±15V
RL = 10kΩ
100
1k
FREQUENCY (Hz)
10k
100k
07527-048
CHANNEL SEPARATION (dB)
–20
Figure 51. Channel Separation vs. Frequency
Rev. 0 | Page 14 of 20
AD8622
APPLICATIONS INFORMATION
INPUT PROTECTION
VIN
The maximum differential input voltage that can be applied to
the AD8622 is determined by the internal diodes connected
across its inputs and series resistors at each input. These internal
diodes and series resistors limit the maximum differential input
voltage to ±10 V and are needed to prevent base-emitter junction
breakdown from occurring in the input stage of the AD8622
when very large differential voltages are applied. In addition,
the internal resistors limit the currents that flow through the
diodes. However, in applications where large differential voltages
can be inadvertently applied to the device, large currents may
still flow through these diodes. In such a case, external resistors
must be placed at both inputs of the op amp to limit the input
currents to ±10 mA (see Figure 52).
VSY = ±15V
07527-053
VOLTAGE (5V/DIV)
VOUT
TIME (200µs/DIV)
Figure 53. No Phase Reversal
MICROPOWER INSTRUMENTATION AMPLIFIER
The AD8622 is a dual, high precision, rail-to-rail output op amp
operating at just 215 μA quiescent current per amplifier. Its
ultralow offset, offset drift, and voltage noise, combined with its
very low bias current and high common-mode rejection ratio
(CMRR), are ideally suited for high accuracy and micropower
instrumentation amplifier.
2 500Ω
1/2
AD8622
3 500Ω
07527-055
R2
1
Figure 52. Input Protection
PHASE REVERSAL
An undesired phenomenon, phase reversal (also known as
phase inversion) occurs in many op amps when one or both of
the inputs are driven beyond the specified input voltage range
(IVR), in effect reversing the polarity of the output. In some
cases, phase reversal can induce lockups and even cause
equipment damage as well as self destruction.
The AD8622 amplifiers have been carefully designed to prevent
output phase reversal when both inputs are maintained within
the specified input voltage range. In addition, even if one or
both inputs exceed the input voltage range but remain within
the supply rails, the output still does not phase reverse. Figure 53
shows the input/output waveforms of the AD8622 configured as a
unity-gain buffer with a supply voltage of ±15 V.
Figure 54 shows the classic 2-op-amp instrumentation amplifier
with four resistors using the AD8622. The key to high CMRR
for this instrumentation amplifier are resistors that are well
matched from both the resistive ratio and the relative drift. For
true difference amplification, matching of the resistor ratio is
very important, where R3/R4 = R1/R2. Assuming perfectly
matched resistors, the gain of the circuit is 1 + R2/R1, which is
approximately 100. Tighter matching of two op amps in one
package, like the AD8622, offers a significant boost in
performance over the classical 3-op-amp configuration. Overall,
the circuit only requires about 430 μA of supply current.
R3
10.1kΩ
R4
1MΩ
–
1/2
AD8622
V1
R2
1MΩ
+15V
R1
10.1kΩ
+15V
–
1/2
AD8622
+
–15V
V2
VO
+
NOTES
–15V
1. VO = 100(V2 – V1)
2. TYPICAL: 0.01mV < |V2 – V1| < 149.7mV
3. TYPICAL: –14.97V < VO < +14.97V
4. USE MATCHED RESISTORS.
07527-054
R1
Figure 54. Micropower Instrumentation Amplifier
Rev. 0 | Page 15 of 20
AD8622
The ADR121 is a precision micropower 2.5 V voltage reference.
A precision voltage reference is required to hold a constant current
so that the Hall voltage only depends on the intensity of the magnetic field. Using the 4.12k:98.8k resistive divider, the bias
voltage of the Hall element is reduced to 100 mV, leading to only
250 μA of power consumption. The 3-op-amp in-amp
configuration of the AD8622 then increases the sensitivity to
55 mV/mT. Using the AD8622 to amplify the sensor signal can
reduce power while also achieving higher sensitivity. The total
current consumed is just 1.2 mA, resulting in 21× improvement in
sensitivity/power.
HALL SENSOR SIGNAL CONDITIONING
The AD8622 is also highly suitable for high accuracy, low power
signal conditioning circuits. One such use is in Hall sensor
signal conditioning (see Figure 55). The magnetic sensitivity of
a Hall element is proportional to the bias voltage applied across
it. With 1 V bias voltage, the Hall element consumes about
2.5 mA of supply current and has a sensitivity of 5.5 mV/mT
typical. To reduce power consumption, bias voltage must be
reduced, but at the risk of lower sensitivity. The only way to
achieve higher sensitivity is by introducing a gain using a
precision micropower amplifier. The AD8622, with all its
features, is well suited to amplify the sensitivity of the Hall
element.
VSY
VSY
C1
1µF TO 10µF
HALL
ELEMENT
1/2
–
VSY
ADR121 –2.5V
VSY
4.12kΩ
C2
0.1µF
C3
+
0.1µF
TO 10µF
+
98.8kΩ
1/2
400Ω
×4
9.9kΩ
AD8622
9.9kΩ
9.9kΩ
9.9kΩ
9.9kΩ
200Ω
AD8622
VSY
–
–
–
1/2
AD8622
+
VOUT = 2.5V +
55mV
× MAGNETIC FIELD (mT)
mT
1/2
AD8622
+
NOTES
1. USE MATCHED RESISTORS FOR IN-AMP.
2. FOR INFORMATION ON C1, C2, AND C3, REFER TO ADR121 DATA SHEET.
Figure 55. Hall Sensor Signal Conditioning
Rev. 0 | Page 16 of 20
9.9kΩ
07527-052
+
AD8622
SIMPLIFIED SCHEMATIC
V+
R3
R2
R1
Q11
Q10
C1
Q4
–IN x
500Ω
500Ω
Q1
D1
INPUT BIAS
CANCELLATION
CIRCUITRY
Q6
Q5
Q8
OUT x
Q2
D2
Q7
D3
V–
Figure 56. Simplified Schematic
Rev. 0 | Page 17 of 20
Q9
D4
Q12
07527-062
+IN x
VB2
VB1
Q3
AD8622
OUTLINE DIMENSIONS
3.20
3.00
2.80
8
3.20
3.00
2.80
5.15
4.90
4.65
5
1
4
PIN 1
0.65 BSC
0.95
0.85
0.75
1.10 MAX
0.15
0.00
0.38
0.22
COPLANARITY
0.10
0.80
0.60
0.40
8°
0°
0.23
0.08
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 57. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
5.00 (0.1968)
4.80 (0.1890)
8
1
5
6.20 (0.2441)
5.80 (0.2284)
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
SEATING
PLANE
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
0.50 (0.0196)
0.25 (0.0099)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-012-A A
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
012407-A
4.00 (0.1574)
3.80 (0.1497)
Figure 58. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model
AD8622ARMZ 1
AD8622ARMZ-REEL1
AD8622ARMZ-R71
AD8622ARZ1
AD8622ARZ-REEL1
AD8622ARZ-REEL71
1
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Package Description
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
Z = RoHS Compliant Part.
Rev. 0 | Page 18 of 20
Package Option
RM-8
RM-8
RM-8
R-8
R-8
R-8
Branding
A1P
A1P
A1P
AD8622
NOTES
Rev. 0 | Page 19 of 20
AD8622
NOTES
©2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07527-0-7/09(0)
Rev. 0 | Page 20 of 20