Data Sheet
FEATURES
Low offset voltage: 1 μV
Input offset drift: 0.005 μV/°C
Rail-to-rail input and output swing
5 V/2.7 V single-supply operation
High gain: 145 dB typical
CMRR: 140 dB typical
PSRR: 130 dB typical
Ultralow input bias current: 10 pA typical
Low supply current: 750 μA per op amp
Overload recovery time: 50 μs
No external capacitors required
Zero-Drift, Single-Supply, Rail-to-Rail
Input/Output Operational Amplifiers
AD8571/AD8572/AD8574
PIN CONFIGURATIONS
NC
–IN A
+IN A
V–
1
2
3
4
8
NC
V+
OUT A
01104-001
01104-006
AD8571
7
TOP VIEW
6
(Not to Scale)
5
NC
NC = NO CONNECT
Figure 1. 8-Lead MSOP (RM Suffix)
NC
1
–IN A
2
+IN A
3
8
NC
V+
AD8571
7
6
NC = NO CONNECT
APPLICATIONS
Temperature sensors
Pressure sensors
Precision current sensing
Strain gage amplifiers
Medical instrumentation
Thermocouple amplifiers
Figure 2. 8-Lead SOIC (R Suffix)
OUT A
1
–IN A
+IN A
V–
2
3
4
8
V+
OUT B
–IN B
+IN B
01104-002
AD8572
TOP VIEW
(Not to Scale)
7
6
5
Figure 3. 8-Lead TSSOP (RU Suffix)
OUT A
1
–IN A
2
8
V+
OUT B
–IN B
+IN B
01104-005
AD8572
TOP VIEW
(Not to Scale)
7
6
5
+IN A
3
GENERAL DESCRIPTION
This family of amplifiers has ultralow offset, drift, and bias
current. The
AD8571/AD8572/AD8574
1
are single, dual, and
quad amplifiers, respectively, featuring rail-to-rail input and
output swings. All are guaranteed to operate from 2.7 V to 5 V
single supply.
The
AD8571/AD8572/AD8574
provide benefits previously
found only in expensive auto-zeroing or chopper-stabilized
amplifiers. Using Analog Devices, Inc., topology, these zero-
drift amplifiers combine low cost with high accuracy. (No
external capacitors are required.) Using a spread-spectrum,
auto-zero technique, the
AD8571/AD8572/AD8574
eliminate
the intermodulation effects from interaction of the chopping
function with the signal frequency in ac applications.
With an offset voltage of only 1 μV and drift of 0.005 μV/°C, the
AD8571/AD8572/AD8574
are perfectly suited for applications
where error sources cannot be tolerated. Position and pressure
sensors, medical equipment, and strain gage amplifiers benefit
greatly from nearly zero drift over their operating temperature
range. Many more systems require the rail-to-rail input and
output swings provided by the
AD8571/AD8572/AD8574.
1
V–
4
Figure 4. 8-Lead SOIC (R Suffix)
OUT A
1
–IN A
2
+IN A
3
V+
4
+IN B
5
–IN B
6
OUT B
7
14
13
OUT D
–IN D
+IN D
AD8574
12
11
V–
TOP VIEW
(Not to Scale)
10
+IN C
01104-003
9
8
–IN C
OUT C
Figure 5. 14-Lead TSSOP (RU Suffix)
OUT A
1
–IN A
2
+IN A
3
V+
4
+IN B
5
–IN B
6
OUT B
7
14
OUT D
13
–IN D
AD8574
12
+IN D
11
V–
TOP VIEW
(Not to Scale)
10
+IN C
9
8
–IN C
OUT C
Figure 6. 14-Lead SOIC (R Suffix)
Protected by U.S. Patent 6,130,578.
Document Feedback
The
AD8571/AD8572/AD8574
are specified for the extended
industrial/ automotive temperature range (−40°C to +125°C).
The
AD8571
single amplifier is available in 8-lead MSOP and
narrow SOIC packages. The
AD8572
dual amplifier is available in
8-lead narrow SOIC and surface-mount TSSOP packages. The
AD8574
quad amplifier is available in 14-lead narrow SOIC and
TSSOP packages.
Rev. F
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 ©1999–2015 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
01104-004
OUT A
TOP VIEW
(Not to Scale)
5
NC
V–
4
AD8571/AD8572/AD8574
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Pin Configurations ........................................................................... 1
Revision History ............................................................................... 3
Specifications..................................................................................... 4
5 V Electrical Characteristics ...................................................... 4
2.7 V Electrical Characteristics................................................... 5
Absolute Maximum Ratings ............................................................ 6
Thermal Characteristics .............................................................. 6
ESD Caution .................................................................................. 6
Typical Performance Characteristics ............................................. 7
Functional Description .................................................................. 15
Amplifier Architecture .............................................................. 15
Basic Auto-Zero Amplifier Theory .......................................... 15
Auto-Zero Phase ......................................................................... 16
Amplification Phase ................................................................... 16
High Gain, CMRR, and PSRR .................................................. 17
Data Sheet
Maximizing Performance Through Proper Layout ............... 17
1/f Noise Characteristics ........................................................... 18
Random Auto-Zero Correction Eliminates Intermodulation
Distortion .................................................................................... 18
Broadband and External Resistor Noise Considerations .......... 19
Output Overdrive Recovery ...................................................... 19
Input Overvoltage Protection ................................................... 19
Output Phase Reversal ............................................................... 19
Capacitive Load Drive ............................................................... 20
Power-Up Behavior .................................................................... 20
Applications Information .............................................................. 21
5 V Precision Strain Gage Circuit ............................................ 21
3 V Instrumentation Amplifier ................................................ 21
High Accuracy Thermocouple Amplifier ............................... 22
Precision Current Meter ............................................................ 22
Precision Voltage Comparator.................................................. 22
Outline Dimensions ....................................................................... 23
Ordering Guide .......................................................................... 25
Rev. F | Page 2 of 28
Data Sheet
REVISION HISTORY
6/15—Rev. E to Rev. F
Added Patent Note, Note 1............................................................... 1
Change to Input Voltage Parameter, Table 3.................................. 6
Changes to Ordering Guide ...........................................................25
2/11—Rev. D to Rev. E
Changes to Figure 66 ......................................................................21
Updated Outline Dimensions ........................................................22
Changes to Ordering Guide ...........................................................23
6/08—Rev. C to Rev. D
Changes to Figure 19 and Figure 20 ............................................... 8
Changes to Figure 44 ......................................................................12
Changes to Figure 38 ......................................................................13
Moved Figure 50 and Figure 51 .....................................................14
Changes to Figure 66, Precision Current Meter Section, Layout,
Figure 67, Equation 24, and Figure 68 ..........................................21
5/07—Rev. B to Rev. C
Changes to Features .......................................................................... 1
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 4
Changes to Basic Auto-Zero Amplifier Theory Section ............14
Changes to Figure 50 ......................................................................15
Changes to Figure 55 ......................................................................16
Changes to Figure 66 ......................................................................21
Updated Outline Dimensions ........................................................22
AD8571/AD8572/AD8574
9/06—Rev. A to Rev. B
Updated Format ................................................................. Universal
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 4
Changes to Figure 50 ...................................................................... 14
Changes to Figure 51 ...................................................................... 15
Changes to Figure 66 ...................................................................... 21
Deleted Figure 69 and SPICE Macro-Model Section ................. 17
Deleted SPICE Macro-Model for the AD857x Section .............. 18
Updated Outline Dimensions........................................................ 22
Changes to Ordering Guide ........................................................... 23
7/03—Rev. 0 to Rev. A
Renumbered Figures .......................................................... Universal
Changes to Ordering Guide ............................................................. 4
Change to Figure 15. ....................................................................... 16
Updated Outline Dimensions........................................................ 19
10/99—Revision 0: Initial Version
Rev. F | Page 3 of 28
AD8571/AD8572/AD8574
SPECIFICATIONS
5 V ELECTRICAL CHARACTERISTICS
V
S
= 5 V, V
CM
= 2.5 V, V
O
= 2.5 V, T
A
= 25°C, unless otherwise noted.
Table 1.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Input Bias Current
AD8571/AD8574
AD8572
Input Offset Current
AD8571/AD8574
AD8572
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
1
Offset Voltage Drift
OUTPUT CHARACTERISTICS
Output Voltage High
Symbol
V
OS
−40°C ≤ T
A
≤ +125°C
I
B
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +85°C
−40°C ≤ T
A
≤ +125°C
I
OS
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +85°C
−40°C ≤ T
A
≤ +125°C
CMRR
A
VO
∆V
OS
/∆T
V
OH
V
CM
= 0 V to 5 V
−40°C ≤ T
A
≤ +125°C
R
L
= 10 kΩ, V
O
= 0.3 V to 4.7 V
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +125°C
R
L
= 100 kΩ to GND
R
L
= 100 kΩ to GND @ −40°C to +125°C
R
L
= 10 kΩ to GND
R
L
= 10 kΩ to GND @ −40°C to +125°C
R
L
= 100 kΩ to V+
R
L
= 100 kΩ to V+ @ −40°C to +125°C
R
L
= 10 kΩ to V+
R
L
= 10 kΩ to V+ @ −40°C to +125°C
Short-Circuit Limit
Output Current
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Overload Recovery Time
Gain Bandwidth Product
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
1
Data Sheet
Conditions
Min
Typ
1
10
1.0
160
2.5
20
150
30
150
Max
5
10
50
1.5
300
4
70
200
150
400
5
Unit
μV
μV
pA
nA
pA
nA
pA
pA
pA
pA
V
dB
dB
dB
dB
μV/°C
V
V
V
V
mV
mV
mV
mV
mA
mA
mA
mA
dB
dB
μA
μA
V/μs
ms
MHz
μV p-p
μV p-p
nV/√Hz
fA/√Hz
0
120
115
125
120
140
130
145
135
0.005
4.998
4.997
4.98
4.975
1
2
10
15
±50
±40
±30
±15
130
130
850
1000
0.4
0.05
1.5
1.3
0.41
51
2
0.04
4.99
4.99
4.95
4.95
Output Voltage Low
V
OL
10
10
30
30
I
SC
−40°C to +125°C
I
O
−40°C to +125°C
PSRR
I
SY
V
S
= 2.7 V to 5.5 V
−40°C ≤ T
A
≤ +125°C
V
O
= 0 V
−40°C ≤ T
A
≤ +125°C
R
L
= 10 kΩ
±25
120
115
975
1075
SR
GBP
e
n
p-p
e
n
i
n
0.3
0 Hz to 10 Hz
0 Hz to 1 Hz
f = 1 kHz
f = 10 Hz
Gain testing is dependent upon test bandwidth.
Rev. F | Page 4 of 28
Data Sheet
2.7 V ELECTRICAL CHARACTERISTICS
V
S
= 2.7 V, V
CM
= 1.35 V, V
O
= 1.35 V, T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
Input Bias Current
AD8571/AD8574
AD8572
Input Offset Current
AD8571/AD8574
AD8572
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
1
Offset Voltage Drift
OUTPUT CHARACTERISTICS
Output Voltage High
Symbol
V
OS
−40°C ≤ T
A
≤ +125°C
I
B
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +85°C
−40°C ≤ T
A
≤ +125°C
I
OS
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +85°C
−40°C ≤ T
A
≤ +125°C
CMRR
A
VO
∆V
OS
/∆T
V
OH
V
CM
= 0 V to 2.7 V
−40°C ≤ T
A
≤ +125°C
R
L
= 10 kΩ, V
O
= 0.3 V to 2.4 V
−40°C ≤ T
A
≤ +125°C
−40°C ≤ T
A
≤ +125°C
R
L
= 100 kΩ to GND
R
L
= 100 kΩ to GND @ −40°C to +125°C
R
L
= 10 kΩ to GND
R
L
= 10 kΩ to GND @ −40°C to +125°C
R
L
= 100 kΩ to V+
R
L
= 100 kΩ to V+ @ −40°C to +125°C
R
L
= 10 kΩ to V+
R
L
= 10 kΩ to V+ @ −40°C to +125°C
−40°C to +125°C
Output Current
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current per Amplifier
DYNAMIC PERFORMANCE
Slew Rate
Overload Recovery Time
Gain Bandwidth Product
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
1
AD8571/AD8572/AD8574
Conditions
Min
Typ
1
10
1.0
160
2.5
10
150
30
150
Max
5
10
50
1.5
300
4
50
200
150
400
2.7
Unit
μV
μV
pA
nA
pA
nA
pA
pA
pA
pA
V
dB
dB
dB
dB
µV/°C
V
V
V
V
mV
mV
mV
mV
mA
mA
mA
mA
dB
dB
μA
μA
V/μs
ms
MHz
μV p-p
nV/√Hz
fA/√Hz
0
115
110
110
105
130
130
140
130
0.005
2.697
2.696
2.68
2.675
1
2
10
15
±15
±10
±10
±5
130
130
750
950
0.5
0.05
1
2.0
94
2
0.04
2.685
2.685
2.67
2.67
Output Voltage Low
V
OL
10
10
20
20
Short-Circuit Limit
I
SC
I
O
−40°C to +125°C
PSRR
I
SY
V
S
= 2.7 V to 5.5 V
−40°C ≤ T
A
≤ +125°C
V
O
= 0 V
−40°C ≤ T
A
≤ +125°C
R
L
= 10 kΩ
±10
120
115
900
1000
SR
GBP
e
n
p-p
e
n
i
n
0 Hz to 10 Hz
f = 1 kHz
f = 10 Hz
Gain testing is dependent upon test bandwidth.
Rev. F | Page 5 of 28
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