a
FEATURES
EASY TO USE
Pin-Strappable Gains of 10 and 100
All Errors Specified for Total System Performance
Higher Performance than Discrete In Amp Designs
Available in 8-Lead DIP and SOIC
Low Power, 1.3 mA Max Supply Current
Wide Power Supply Range ( 2.3 V to 18 V)
EXCELLENT DC PERFORMANCE
0.15% Max, Total Gain Error
5 ppm/ C, Total Gain Drift
125 V Max, Total Offset Voltage
1.0 V/ C Max, Offset Voltage Drift
LOW NOISE
9 nV/√Hz, @ 1 kHz, Input Voltage Noise
0.28 V p-p Noise (0.1 Hz to 10 Hz)
EXCELLENT AC SPECIFICATIONS
800 kHz Bandwidth (G = 10), 200 kHz (G = 100)
12 s Settling Time to 0.01%
APPLICATIONS
Weigh Scales
Transducer Interface and Data Acquisition Systems
Industrial Process Controls
Battery-Powered and Portable Equipment
PRODUCT DESCRIPTION
Low Drift, Low Power
Instrumentation Amplifier
AD621
CONNECTION DIAGRAM
8-Lead Plastic Mini-DIP (N), Cerdip (Q)
and SOIC (R) Packages
G = 10/100
1
–IN
2
8
G = 10/100
AD621
7
+V
S
TOP VIEW
6
OUTPUT
+IN
3
(Not to Scale)
5
REF
–V
S 4
gain drift errors are achieved by the use of internal gain setting
resistors. Fixed gains of 10 and 100 can easily be set via external
pin strapping. The AD621 is fully specified as a total system,
therefore, simplifying the design process.
For portable or remote applications, where power dissipation,
size, and weight are critical, the AD621 features a very low
supply current of 1.3 mA max and is packaged in a compact
8-lead SOIC, 8-lead plastic DIP or 8-lead cerdip. The AD621
also excels in applications requiring high total accuracy, such
as precision data acquisition systems used in weigh scales and
transducer interface circuits. Low maximum error specifications
including nonlinearity of 10 ppm, gain drift of 5 ppm/°C, 50
µV
offset voltage, and 0.6
µV/°C
offset drift (“B” grade), make
possible total system performance at a lower cost than has been
previously achieved with discrete designs or with other mono-
lithic instrumentation amplifiers.
When operating from high source impedances, as in ECG and
blood pressure monitors, the AD621 features the ideal combina-
tion of low noise and low input bias currents. Voltage noise is
specified as 9 nV/√Hz at 1 kHz and 0.28
µV
p-p from 0.1 Hz to
10 Hz. Input current noise is also extremely low at 0.1 pA/√Hz.
The AD621 outperforms FET input devices with an input bias
current specification of 1.5 nA max over the full industrial tem-
perature range.
Vp-p
The AD621 is an easy to use, low cost, low power, high accu-
racy instrumentation amplifier that is ideally suited for a wide
range of applications. Its unique combination of high perfor-
mance, small size and low power, outperforms discrete in amp
implementations. High functionality, low gain errors, and low
30,000
TOTAL ERROR, ppm OF FULL SCALE
25,000
3 OP AMP
IN AMP
(3 OP 07
S
)
10,000
20,000
TOTAL INPUT VOLTAGE NOISE, G = 100 –
(0.1 – 10Hz)
15,000
1,000
TYPICAL STANDARD
BIPOLAR INPUT
IN AMP
10,000
AD621A
100
5,000
10
AD621 SUPER ETA
BIPOLAR INPUT
IN AMP
0
0
5
10
SUPPLY CURRENT – mA
15
20
1
Figure 1. Three Op Amp IA Designs vs. AD621
0.1
1k
10k
100k
1M
SOURCE RESISTANCE –
10M
100M
REV. B
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Figure 2. Total Voltage Noise vs. Source Resistance
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001
AD621* PRODUCT PAGE QUICK LINKS
Last Content Update: 02/23/2017
COMPARABLE PARTS
View a parametric search of comparable parts.
TOOLS AND SIMULATIONS
•
In-Amp Error Calculator
EVALUATION KITS
•
AD62x, AD822x, AD842x Series InAmp Evaluation Board
REFERENCE MATERIALS
Technical Articles
•
Auto-Zero Amplifiers
•
High-performance Adder Uses Instrumentation Amplifiers
•
Input Filter Prevents Instrumentation-amp RF-
Rectification Errors
•
The AD8221 - Setting a New Industry Standard for
Instrumentation Amplifiers
DOCUMENTATION
Application Notes
•
AN-1401: Instrumentation Amplifier Common-Mode
Range: The Diamond Plot
•
AN-214: Ground Rules for High Speed Circuits
•
AN-244: A User's Guide to I.C. Instrumentation Amplifiers
•
AN-245: Instrumentation Amplifiers Solve Unusual Design
Problems
•
AN-282: Fundamentals of Sampled Data Systems
•
AN-589: Ways to Optimize the Performance of a
Difference Amplifier
•
AN-671: Reducing RFI Rectification Errors in In-Amp
Circuits
Data Sheet
•
AD621: Low Drift, Low Power Instrumentation Amp with
fixed gains of 10 and 100 Data Sheet
Technical Books
•
A Designer's Guide to Instrumentation Amplifiers, 3rd
Edition, 2006
User Guides
•
UG-261: Evaluation Boards for the AD62x, AD822x and
AD842x Series
DESIGN RESOURCES
•
AD621 Material Declaration
•
PCN-PDN Information
•
Quality And Reliability
•
Symbols and Footprints
DISCUSSIONS
View all AD621 EngineerZone Discussions.
SAMPLE AND BUY
Visit the product page to see pricing options.
TECHNICAL SUPPORT
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number.
DOCUMENT FEEDBACK
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This page is dynamically generated by Analog Devices, Inc., and inserted into this data sheet. A dynamic change to the content on this page will not
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AD621–SPECIFICATIONS
Gain = 10
(Typical @ 25 C, V =
S
15 V, and R
L
= 2 k , unless otherwise noted.)
Min
AD621A
Typ
Max
Min
AD621B
Typ
Max
Min
AD621S
1
Typ
Max
Unit
Model
GAIN
Gain Error
Nonlinearity,
V
OUT
= –10 V to +10 V
Gain vs. Temperature
TOTAL VOLTAGE OFFSET
Offset (RTI)
Over Temperature
Average TC
Offset Referred to the
Input vs. Supply (PSR)
2
Total NOISE
Voltage Noise (RTI)
RTI
Current Noise
INPUT CURRENT
Input Bias Current
Over Temperature
Average TC
Input Offset Current
Over Temperature
Average TC
INPUT
Input Impedance
Differential
Common-Mode
Input Voltage Range
3
Over Temperature
Over Temperature
Common-Mode Rejection
Ratio DC to 60 Hz with
1 kΩ Source Imbalance
OUTPUT
Output Swing
Over Temperature
Conditions
V
OUT
=
±
10 V
R
L
= 2 kΩ
0.15
2
–1.5
75
1.0
95
120
13
0.55
100
10
0.5
3.0
0.3
1.5
17
10
±
5
250
400
2.5
100
2
–1.5
50
0.6
120
13
0.55
100
10
0.5
3.0
0.3
1.5
0.05
10
±
5
125
215
1.5
95
17
0.8
2
–1
75
1.0
120
13
0.55
100
10
0.5
8.0
0.3
8.0
0.15
10
±
5
250
500
2.5
%
ppm of FS
ppm/°C
µV
µV
µV/°C
dB
V
S
=
±
15 V
V
S
=
±
5 V to
±
15 V
V
S
=
±
5 V to
±
15 V
V
S
=
±
2.3 V to
±
18 V
1 kHz
0.1 Hz to 10 Hz
f = 1 kHz
0.1 Hz–10 Hz
V
S
=
±
15 V
17
0.8
nV/√Hz
µV
p-p
fA/√Hz
pA p-p
nA
nA
pA/°C
nA
nA
pA/°C
2.0
2.5
1.0
1.5
1.0
1.5
0.5
0.75
2
4
1.0
2.0
10 2
10 2
V
S
=
±
2.3 V to
±
5 V
V
S
=
±
5 V to
±
18 V
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.1
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.1
10 2
10 2
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.3
10 2
10 2
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
GΩ pF
GΩ pF
V
V
V
V
V
CM
= 0 V to
±
10 V
R
L
= 10 kΩ,
V
S
=
±
2.3 V to
±
5 V
V
S
=
±
5 V to
±
18 V
93
110
100
110
93
110
dB
Over Temperature
Short Current Circuit
DYNAMIC RESPONSE
Small Signal,
–3 dB Bandwidth
Slew Rate
Settling Time to 0.01%
REFERENCE INPUT
R
IN
I
IN
Voltage Range
Gain to Output
POWER SUPPLY
Operating Range
Quiescent Current
Over Temperature
TEMPERATURE RANGE
For Specified Performance
1
–V
S
+ 1.1
–V
S
+ 1.4
–V
S
+ 1.2
–V
S
+ 1.6
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
–V
S
+ 1.1
–V
S
+ 1.4
–V
S
+ 1.2
–V
S
+ 1.6
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
–V
S
+ 1.1
–V
S
+ 1.6
–V
S
+ 1.2
–V
S
+ 2.3
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
V
V
V
V
mA
0.75
10 V Step
800
1.2
12
20
50
0.75
800
1.2
12
20
50
1
±
0.0001
0.75
800
1.2
12
20
+50
kHz
V/µs
µs
kΩ
µA
V
V
IN
+, V
REF
= 0
–V
S
+ 1.6
60
+V
S
– 1.6 –V
S
+ 1.6
60
+V
S
– 1.6
V
S
+ 1.6
1
±
0.0001
±
2.3
0.9
1.1
–40 to +85
±
18
1.3
1.6
±
2.3
+60
+V
S
– 1.6
1
±
0.0001
±
18
1.3
1.6
V
S
=
±
2.3 V to
±
18 V
0.9
1.1
–40 to +85
±
18
1.3
1.6
±
2.3
0.9
1.1
V
mA
mA
°C
–55 to +125
NOTES
See Analog Devices’ military data sheet for 883B tested specifications.
2
This is defined as the supply range over which PSRR is defined.
3
Input Voltage Range = CMV + (Gain
×
V
DIFF
).
Specifications subject to change without notice.
–2–
REV. B
AD621
Gain = 100
Model
GAIN
Gain Error
Nonlinearity,
V
OUT
= –10 V to +10 V
Gain vs. Temperature
TOTAL VOLTAGE OFFSET
Offset (RTI)
Over Temperature
Average TC
Offset Referred to the
Input vs. Supply (PSR)
2
Total NOISE
Voltage Noise (RTI)
RTI
Current Noise
INPUT CURRENT
Input Bias Current
Over Temperature
Average TC
Input Offset Current
Over Temperature
Average TC
INPUT
Input Impedance
Differential
Common-Mode
Input Voltage Range
3
Over Temperature
Over Temperature
Common-Mode Rejection
Ratio DC to 60 Hz with
1 kΩ Source Imbalance
OUTPUT
Output Swing
Over Temperature
V
S
=
±
5 V to
±
18 V
Over Temperature
Short Current Circuit
DYNAMIC RESPONSE
Small Signal,
–3 dB Bandwidth
Slew Rate
Settling Time to 0.01%
REFERENCE INPUT
R
IN
I
IN
Voltage Range
Gain to Output
POWER SUPPLY
Operating Range
Quiescent Current
Over Temperature
TEMPERATURE RANGE
For Specified Performance
1
(Typical @ 25 C, V
S
=
Conditions
V
OUT
=
±
10 V
R
L
= 2 kΩ
15 V, and R
L
= 2 k , unless otherwise noted.)
Min
AD621A
Typ
Max
Min
AD621B
Typ
Max
Min
AD621S
1
Typ
Max
Unit
0.15
2
–1
35
0.3
110
140
9
0.28
100
10
0.5
3.0
0.3
1.5
13
10
±
5
125
185
1.0
120
2
–1
25
0.1
140
9
0.28
100
10
0.5
3.0
0.3
1.5
0.05
10
±
5
50
215
0.6
110
13
0.4
2
–1
35
0.3
140
9
0.28
100
10
0.5
8.0
0.3
8.0
0.15
10
±
5
125
225
1.0
%
ppm of FS
ppm/°C
µV
µV
µV/°C
dB
V
S
=
±
15 V
V
S
=
±
5 V to
±
15 V
V
S
=
±
5 V to
±
15 V
V
S
=
±
2.3 V to
±
18 V
1 kHz
0.1 Hz to 10 Hz
f = 1 kHz
0.1 Hz–10 Hz
V
S
=
±
15 V
13
0.4
nV/√Hz
µV
p-p
fA/√Hz
pA p-p
nA
nA
pA/°C
nA
nA
pA/°C
2.0
2.5
1.0
1.5
1.0
1.5
0.5
0.75
2
4
1.0
2.0
10 2
10 2
V
S
=
±
2.3 V to
±
5 V
V
S
=
±
5 V to
±
18 V
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.1
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.1
10 2
10 2
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
–V
S
+ 1.9
–V
S
+ 2.1
–V
S
+ 1.9
–V
S
+ 2.3
10 2
10 2
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.4
GΩ pF
GΩ pF
V
V
V
V
V
CM
= 0 V to
±
10 V
R
L
= 10 kΩ,
V
S
=
±
2.3 V to
±
5 V
110
130
120
130
110
130
dB
–V
S
+ 1.1
–V
S
+ 1.4
–V
S
+ 1.2
–V
S
+ 1.6
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
–V
S
+ 1.1
–V
S
+ 1.4
–V
S
+ 1.2
–V
S
+ 1.6
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
–V
S
+ 1.1
–V
S
+ 1.6
–V
S
+ 1.2
–V
S
+ 2.3
±
18
+V
S
– 1.2
+V
S
– 1.3
+V
S
– 1.4
+V
S
– 1.5
V
V
V
V
mA
0.75
10 V Step
200
1.2
12
20
50
0.75
200
1.2
12
20
50
1
±
0.0001
0.75
200
1.2
12
20
50
kHz
V/µs
µs
kΩ
µA
V
V
IN
+, V
REF
= 0
–V
S
+ 1.6
60
+V
S
– 1.6 –V
S
+ 1.6
60
+V
S
– 1.6
V
S
+ 1.6
1
±
0.0001
±
2.3
0.9
1.1
–40 to +85
±
18
1.3
1.6
±
2.3
60
+V
S
– 1.6
1
±
0.0001
±
18
1.3
1.6
V
S
=
±
2.3 V to
±
18 V
0.9
1.1
–40 to +85
±
18
1.3
1.6
±
2.3
0.9
1.1
V
mA
mA
°C
–55 to +125
NOTES
See Analog Devices’ military data sheet for 883B tested specifications.
2
This is defined as the supply range over which PSEE is defined.
3
Input Voltage Range = CMV + (Gain
×
V
DIFF
).
Specifications subject to change without notice.
REV. B
–3–
AD621
ABSOLUTE MAXIMUM RATINGS
1
ESD SUSCEPTIBILITY
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
18 V
Internal Power Dissipation
2
. . . . . . . . . . . . . . . . . . . . 650 mW
Input Voltage (Common Mode) . . . . . . . . . . . . . . . . . . . .
±
V
S
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . .
±
25 V
Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite
Storage Temperature Range (Q) . . . . . . . . . –65°C to +150°C
Storage Temperature Range (N, R) . . . . . . . –65°C to +125°C
Operating Temperature Range
AD621 (A, B) . . . . . . . . . . . . . . . . . . . . . . – 40°C to +85°C
AD621 (S) . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to +125°C
Lead Temperature Range
(Soldering 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . . 300°C
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent 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.
2
Specification is for device in free air:
8-Lead Plastic Package:
θ
JA
= 95°C/W
8-Lead Cerdip Package:
θ
JA
= 110°C/W
8-Lead SOIC Package:
θ
JA
= 155°C/W
ESD (electrostatic discharge) sensitive device. Electrostatic
charges as high as 4000 volts, which readily accumulate on the
human body and on test equipment, can discharge without
detection. Although the AD621 features proprietary ESD pro-
tection circuitry, permanent damage may still occur on these
devices if they are subjected to high energy electrostatic dis-
charges. Therefore, proper ESD precautions are recommended
to avoid any performance degradation or loss of functionality.
ORDERING GUIDE
Model
AD621AN
AD621BN
AD621AR
AD621BR
AD621SQ/883B
2
AD621ACHIPS
Temperature
Range
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–55°C to +125°C
–40°C to +85°C
Package
Description
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead Plastic SOIC
8-Lead Plastic SOIC
8-Lead Cerdip
Die
Package
Option
1
N-8
N-8
R-8
R-8
Q-8
NOTES
1
N = Plastic DIP; Q = Cerdip; R = SOIC.
2
See Analog Devices’ military data sheet for 883B specifications.
METALIZATION PHOTOGRAPH
Dimensions shown in inches and (mm).
Contact factory for latest dimensions.
1.125 (3.57)
+V
S
7
OUTPUT
6
RG 8
5
REFERENCE
0.0708
(2.545)
RG 1
4 –V
S
2
–IN
3
+IN
–4–
REV. B
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