AD622ARZ-R7 [ADI]
Low Cost Instrumentation Amplifier;
| 型号： | AD622ARZ-R7 |
| 厂家： | 
ADI |
| 描述： | Low Cost Instrumentation Amplifier 放大器 光电二极管 |
| 文件： | 总17页 (文件大小：308K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Cost Instrumentation Amplifier
Data Sheet
AD622
FEATURES
PIN CONFIGURATION
R
1
2
3
4
Easy to use
Low cost solution
8
7
6
5
R
G
G
AD622
–IN
+IN
+V
S
Higher performance than two or three op amp design
Unity gain with no external resistor
Optional gains with one external resistor
(Gain range: 2 to 1000)
Wide power supply range: 2.6 V to 15 V
Available in 8-lead PDIP and 8-lead SOIC_N packages
Low power, 1.5 mA maximum supply current
DC performance
OUTPUT
REF
–V
S
Figure 1. 8-Lead PDIP and 8-Lead SOIC_N
(N and R Suffixes)
GENERAL DESCRIPTION
The AD622 is a low cost, moderately accurate instrumentation
amplifier in the traditional pin configuration that requires only
one external resistor to set any gain between 2 and 1000. For a
gain of 1, no external resistor is required. The AD622 is a
complete difference or subtractor amplifier system that also
provides superior linearity and common-mode rejection by
incorporating precision laser-trimmed resistors.
0.15% gain accuracy: G = 1
125 µV maximum input offset voltage
1.0 µV/°C maximum input offset drift
5 nA maximum input bias current
66 dB minimum common-mode rejection ratio: G = 1
Noise
The AD622 replaces low cost, discrete, two or three op amp
instrumentation amplifier designs and offers good common-
mode rejection, superior linearity, temperature stability,
reliability, power, and board area consumption. The low cost of
the AD622 eliminates the need to design discrete
instrumentation amplifiers to meet stringent cost targets. While
providing a lower cost solution, it also provides performance
and space improvements.
12 nV/√Hz @ 1 kHz input voltage noise
0.60 µV p-p noise: 0.1 Hz to 10 Hz, G = 10
AC characteristics
800 kHz bandwidth: G = 10
10 µs settling time to 0.1% @ G = 1 to 100
1.2 V/µs slew rate
APPLICATIONS
Transducer interface
Table 1. Next Generation Upgrades for AD622
Low cost thermocouple amplifier
Industrial process controls
Difference amplifier
Part
Comment
Better specs at lower price
Dual channel or differential out
Low power, wide input range
JFET input
Best gain accuracy
+2 precision op amps or differential out
Low noise, better specs
AD8221
AD8222
AD8226
AD8220
AD8228
AD8295
AD8421
Low cost data acquisition
Rev. E
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 ©1996–2012 Analog Devices, Inc. All rights reserved.
AD622* PRODUCT PAGE QUICK LINKS
Last Content Update: 02/23/2017
COMPARABLE PARTS
View a parametric search of comparable parts.
REFERENCE MATERIALS
Technical Articles
• Auto-Zero Amplifiers
EVALUATION KITS
• AD62x, AD822x, AD842x Series InAmp Evaluation Board
• High-performance Adder Uses Instrumentation Amplifiers
• Input Filter Prevents Instrumentation-amp RF-
Rectification Errors
DOCUMENTATION
Application Notes
• The AD8221 - Setting a New Industry Standard for
Instrumentation Amplifiers
• AN-1401: Instrumentation Amplifier Common-Mode
Range: The Diamond Plot
DESIGN RESOURCES
• AD622 Material Declaration
• PCN-PDN Information
• Quality And Reliability
• Symbols and Footprints
• 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
DISCUSSIONS
View all AD622 EngineerZone Discussions.
• AN-671: Reducing RFI Rectification Errors in In-Amp
Circuits
Data Sheet
SAMPLE AND BUY
Visit the product page to see pricing options.
• AD622: Low Cost Instrumentation Amplifier Data Sheet
Technical Books
• A Designer's Guide to Instrumentation Amplifiers, 3rd
Edition, 2006
TECHNICAL SUPPORT
Submit a technical question or find your regional support
number.
User Guides
• UG-261: Evaluation Boards for the AD62x, AD822x and
AD842x Series
DOCUMENT FEEDBACK
Submit feedback for this data sheet.
TOOLS AND SIMULATIONS
• In-Amp Error Calculator
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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AD622
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Theory of Operation .........................................................................9
Make vs. Buy: A Typical Application Error Budget..................9
Gain Selection................................................................................. 11
Input and Output Offset Voltage.............................................. 11
Reference Terminal .................................................................... 11
Input Protection ......................................................................... 11
RF Interference ........................................................................... 12
Ground Returns for Input Bias Currents ................................ 12
Outline Dimensions....................................................................... 13
Ordering Guide .......................................................................... 14
Applications....................................................................................... 1
Pin Configuration............................................................................. 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Typical Performance Characteristics ............................................. 6
REVISION HISTORY
6/12—Rev. D to Rev. E
Added Large Input Voltages at Large Gains Section ................. 11
Replaced RF Interference Section ................................................ 11
Deleted Grounding Section .......................................................... 10
Deleted Figure 16............................................................................ 10
Changes to Ground Returns for Input Bias Currents Section.. 12
Updated Outline Dimensions....................................................... 13
Changes to Ordering Guide.......................................................... 14
Changes to General Description Section; Added Table 1 ........... 1
Changes to Theory of Operation Section and Figure 16............. 9
Changes to Table 5.......................................................................... 10
Changes to Input Selection Section; Deleted Large Input
Voltages at Large Gains Section; Added Figure 18, Renumbered
Sequentially ..................................................................................... 11
Changes to Ordering Guide .......................................................... 14
8/07—Rev. C to Rev. D
4/99—Rev. B to Rev. C
8/98—Rev. A to Rev. B
Updated Format..................................................................Universal
Added Thermal Resistance Section ............................................... 5
Added Figure 16................................................................................ 9
2/97—Rev. 0 to Rev. A
1/96—Revision 0: Initial Version
Rev. E | Page 2 of 16
Data Sheet
AD622
SPECIFICATIONS
TA = 25°C, VS = 15 V, and RL = 2 kΩ typical, unless otherwise noted.
Table 2.
Parameter
Conditions
Min
Typ
Max
Unit
GAIN
G = 1 + (50.5 k/RG)
Gain Range
Gain Error1
G = 1
G = 10
G = 100
1
1000
VOUT
=
10 V
0.05
0.2
0.2
0.15
0.50
0.50
0.50
%
%
%
%
G = 1000
Nonlinearity
0.2
VOUT
=
10 V
G = 1 to 1000
G = 1 to 100
RL = 10 kΩ
RL = 2 kΩ
10
10
ppm
ppm
Gain vs. Temperature
Gain = 1
Gain > 11
10
−50
ppm/°C
ppm/°C
VOLTAGE OFFSET
Input Offset, VOSI
Total RTI Error = VOSI + VOSO/G
VS = 5 V to 15 V
VS = 5 V to 15 V
VS = 5 V to 15 V
VS = 5 V to 15 V
VS = 5 V to 15 V
60
125
1.0
1500
15
µV
µV/°C
µV
Average Temperature Coefficient
Output Offset, VOSO
Average Temperature Coefficient
Offset Referred to Input vs. Supply (PSR)
G = 1
G = 10
G = 100
G = 1000
600
µV/°C
80
95
110
110
100
120
140
140
dB
dB
dB
dB
INPUT CURRENT
Input Bias Current
Average Temperature Coefficient
Input Offset Current
Average Temperature Coefficient
INPUT
2.0
3.0
0.7
2.0
5.0
2.5
nA
pA/°C
nA
pA/°C
Input Impedance
Differential
Common Mode
Input Voltage Range2
10||2
10||2
G Ω||pF
GΩ||pF
V
V
V
V
VS = 2.6 V to 5 V
VS = 5 V to 18 V
VCM = 0 V to 10 V
−VS + 1.9
−VS + 2.1
−VS + 1.9
−VS + 2.1
+VS – 1.2
+VS – 1.3
+VS – 1.4
+VS – 1.4
Over Temperature
Over Temperature
Common-Mode Rejection Ratio
DC to 60 Hz with 1 kΩ Source Imbalance
G = 1
G = 10
G = 100
66
86
103
103
78
98
118
118
dB
dB
dB
dB
G = 1000
OUTPUT
Output Swing
RL = 10 kΩ
VS = 2.6 V to 5 V
−VS + 1.1
−VS + 1.4
−VS + 1.2
−VS + 1.6
+VS – 1.2
+VS – 1.3
+VS – 1.4
+VS – 1.5
V
V
V
V
Over Temperature
VS = 5 V to 18 V
Over Temperature
Short Current Circuit
18
mA
Rev. E | Page 3 of 16
AD622
Data Sheet
Parameter
Conditions
Min
Typ
Max
Unit
DYNAMIC RESPONSE
Small Signal −3 dB Bandwidth
G = 1
G = 10
G = 100
G = 1000
Slew Rate
1000
800
120
12
kHz
kHz
kHz
kHz
V/µs
1.2
Settling Time to 0.1%
G = 1 to 100
10 V step
10
µs
NOISE
Voltage Noise, 1 kHz
Input Voltage Noise, eni
Output Voltage Noise, eno
RTI, 0.1 Hz to 10 Hz
G = 1
Total RTI Noise = √(e2ni) + (eno∕G)2
12
72
nV/√Hz
nV/√Hz
4.0
0.6
0.3
100
10
µV p-p
µV p-p
µV p-p
fA/√Hz
pA p-p
G = 10
G = 100
Current Noise
0.1 Hz to 10 Hz
REFERENCE INPUT
RIN
f = 1 kHz
20
50
kΩ
µA
IIN
VIN+, VREF = 0
60
Voltage Range
Gain to Output
POWER SUPPLY
Operating Range3
Quiescent Current
Over Temperature
TEMPERATURE RANGE
For Specified Performance
−VS + 1.6
2.6
+VS – 1.6
V
1
0.0015
18
1.3
1.5
V
mA
mA
VS = 2.6 V to 18 V
0.9
1.1
−40 to +85
°C
1 Does not include effects of External Resistor RG.
2 One input grounded, G = 1.
3 Defined as the same supply range that is used to specify PSR.
Rev. E | Page 4 of 16
Data Sheet
AD622
ABSOLUTE MAXIMUM RATINGS
Table 3.
THERMAL RESISTANCE
θJA is specified for the device in free air.
Parameter
Rating
Supply Voltage
Internal Power Dissipation
Input Voltage (Common Mode)
Differential Input Voltage
Output Short Circuit Duration
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec)
18 V
650 mW
VS
Table 4. Thermal Resistance
Package Type
1
θJA
Unit
8-Lead PDIP (N-8)
8-Lead SOIC_N (R-8)
95
155
°C/W
°C/W
2
25 V
Indefinite
−65°C to +125°C
−40°C to +85°C
300°C
ESD CAUTION
1 Specification is for device in free air; see Table 4.
2 May be further restricted for gains greater than 14. See the Input Protection
section for more information.
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. E | Page 5 of 16
AD622
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VS = 15 V, RL = 2 kΩ, unless otherwise noted.
50
1000
100
10
SAMPLE SIZE = 191
40
30
20
10
0
GAIN = 1
GAIN = 10
GAIN = 100, 1000
GAIN = 1000
BW LIMIT
1
–1.2
–0.8
–0.4
0
0.4
0.8
1.2
1
10
100
1k
10k
100k
OUTPUT OFFSET VOLTAGE (mV)
FREQUENCY (Hz)
Figure 2. Typical Distribution of Output Offset Voltage
Figure 5. Voltage Noise Spectral Density vs. Frequency (G = 1 to 1000)
50
40
30
20
10
0
1000
SAMPLE SIZE = 383
100
10
60
80
100
120
140
1
10
100
FREQUENCY (Hz)
1000
COMMON-MODE REJECTION RATIO (dB)
Figure 3. Typical Distribution of Common-Mode Rejection
Figure 6. Current Noise Spectral Density vs. Frequency
2.0
140
120
100
80
G = 1000
G = 100
G = 10
1.5
1.0
0.5
0
G = 1
60
40
20
0
0
1
2
3
4
5
0.1
1
10
100
1k
10k
100k
1M
WARM-UP TIME (Minutes)
FREQUENCY (Hz)
Figure 4. Change in Input Offset Voltage vs. Warm-Up Time
Figure 7. CMR vs. Frequency, RTI, 0 kΩ to 1 kΩ Source Imbalance
Rev. E | Page 6 of 16
Data Sheet
AD622
180
160
140
120
100
80
30
20
10
0
V
= ±15V
S
G = 10
G = 1000
G = 100
60
G = 10
40
G = 1
20
0.1
1
10
100
1k
10k
100k
1M
10
100
1k
10k
FREQUENCY (Hz)
LOAD RESISTANCE (Ω)
Figure 8. Positive PSR vs. Frequency, RTI (G = 1 to 1000)
Figure 11. Output Voltage Swing vs. Load Resistance
180
160
140
120
100
80
20
15
10
5
TO 0.1%
G = 1000
G = 100
60
G = 10
G = 1
40
0
20
0.1
1
10
100
1k
10k
100k
1M
0
5
10
15
20
FREQUENCY (Hz)
OUTPUT STEP SIZE (V)
Figure 9. Negative PSR vs. Frequency, RTI (G = 1 to 1000)
Figure 12. Settling Time vs. Step Size (G = 1)
1000
100
10
1000
100
10
1
0.1
1
100
1k
10k
100k
1M
10M
1
10
100
1000
FREQUENCY (Hz)
GAIN
Figure 10. Gain vs. Frequency
Figure 13. Settling Time to 0.1% vs. Gain, for a 10 V Step
Rev. E | Page 7 of 16
AD622
Data Sheet
10kΩ
1kΩ
10kΩ
0.1%
0.01% POT
INPUT
20V p-p
V
OUT
100kΩ
0.1%
100
90
+V
7
S
2
1
11kΩ
0.1%
1kΩ
0.1%
100Ω
0.1%
Ø
6
G = 1000
G = 1
G = 100 G = 10
AD622
8
5
3
10
4
0%
–V
S
10µV
2V
Figure 14. Gain Nonlinearity, G = 1, RL = 10 kΩ (20 µV = 2 ppm)
Figure 15. Settling Time Test Circuit
Rev. E | Page 8 of 16
Data Sheet
AD622
THEORY OF OPERATION
The value of RG also determines the transconductance of the
The AD622 is a monolithic instrumentation amplifier based on
a modification of the classic three op amp approach. Absolute
value trimming allows the user to program gain accurately (to
0.5% at G = 1000) with only one resistor. Monolithic construction
and laser wafer trimming allow the tight matching and tracking
of circuit components, thus insuring AD622 performance.
preamp stage. As RG is reduced for larger gains, the trans-
conductance increases asymptotically to that of the input
transistors. This has the following three important advantages:
•
Open-loop gain is boosted for increasing programmed
gain, thus reducing gain-related errors.
•
The gain-bandwidth product (determined by C1, C2, and
the preamp transconductance) increases with programmed
gain, thus optimizing frequency response.
The input voltage noise is reduced to a value of 12 nV/√Hz,
determined mainly by the collector current and base
resistance of the input devices.
Input Transistor Q1 and Input Transistor Q2 provide a single
differential-pair bipolar input for high precision (see Figure 16).
Feedback through the Q1-A1-R1 loop and the Q2-A2-R2 loop
maintains constant collector current of the Q1 and Q2 input
devices, thereby impressing the input voltage across External
Gain-Setting Resistor RG. This creates a differential gain from the
inputs to the A1 and A2 outputs given by G = (R1 + R2)/RG + 1.
Unity-Gain Subtractor A3 removes any common-mode signal,
yielding a single-ended output referred to the REF pin potential.
•
The internal gain resistors, R1 and R2, are trimmed to an
absolute value of 25.25 kΩ, allowing the gain to be programmed
accurately with a single external resistor.
MAKE vs. BUY: A TYPICAL APPLICATION ERROR
BUDGET
+V
S
The AD622 offers cost and performance advantages over
discrete two op amp instrumentation amplifier designs along
with smaller size and fewer components. In a typical application
shown in Figure 17, a gain of 10 is required to receive and
amplify a 0 to 20 mA signal from the AD694 current transmitter.
The current is converted to a voltage in a 50 Ω shunt. In
applications where transmission is over long distances, line
impedance can be significant so that differential voltage
measurement is essential. Where there is no connection
between the ground returns of transmitter and receiver, there
must be a dc path from each input to ground, implemented in
this case using two 1 kΩ resistors. The error budget detailed in
Table 5 shows how to calculate the effect of various error
sources on circuit accuracy.
V
I2
I1
20µA
20µA
C2
B
A1
A2
10kΩ
C1
10kΩ
10kΩ
OUTPUT
REF
A
S
3
10kΩ
+V
+V
S
R1
R2
Q1
Q2
+IN
– IN
R3
400Ω
R4
400Ω
R
G
GAIN
SENSE
GAIN
SENSE
–V
S
Figure 16. Simplified Schematic of the AD622
+
R
L2
1kΩ
10Ω
V
1/2
LT1013
IN
1/2
LT1013
AD694
0 TO 20mA
TRANSMITTER
0 TO 20mA
50Ω
1kΩ
R
G
5.62kΩ
–
AD622
1kΩ
R
L2
10Ω
REF
1kΩ
9kΩ*
1kΩ*
1kΩ*
9kΩ*
*0.1% RESISTOR MATCH, 50ppm/°C TRACKING
HOMEBREW IN-AMP, G = 10
0 TO 20mA CURRENT LOOP
WITH 50Ω SHUNT IMPEDANCE
AD622 MONOLITHIC INSTRUMENTATION
AMPLIFIER, G = 9.986
Figure 17. Make vs. Buy
Rev. E | Page 9 of 16
AD622
Data Sheet
The AD622 provides greater accuracy at lower cost. The higher
cost of the homebrew circuit is dominated in this case by the
matched resistor network. One could also realize a homebrew
design using cheaper discrete resistors that are either trimmed
or hand selected to give high common-mode rejection. This
level of common-mode rejection, however, degrades significantly
over temperature due to the drift mismatch of the discrete
resistors.
Note that for the homebrew circuit, the LT1013 specification for
noise has been multiplied by √2. This is because a two op amp
type instrumentation amplifier has two op amps at its inputs,
both contributing to the overall noise.
Table 5. Make vs. Buy Error Budget
Total Error in ppm
Relative to 1 V FS
Error Source
AD622 Circuit Calculation
Homebrew Circuit Calculation
AD622
Homebrew
ABSOLUTE ACCURACY at TA = 25°C
Total RTI Offset Voltage, µV
Input Offset Current, nA
CMR, dB
125 µV + 1500 µV/10
2.5 nA × 1 kΩ
800 µV × 2
15 nA × 1 kΩ
(0.1% Match × 0.5 V)/10 V
Total Absolute Error
275
2.5
25
1600
15
50
86 dB→50 ppm × 0.5 V
302.5
1665
DRIFT TO 85°C
Gain Drift, ppm/°C
Total RTI Offset Voltage, µV/°C
Input Offset Current, pA/°C
(50 ppm + 5 ppm) × 60°C
(1 µV/°C + 15 µV/°C /10) × 60°C 9 µV/°C × 2 × 60°C
2 pA/°C × 1 kΩ × 60°C
(50 ppm)/°C × 60°C
3300
150
0.12
3000
1080
9.3
155 pA/°C × 1 kΩ × 60°C
Total Drift Error
3450.12
4089.3
RESOLUTION
Gain Nonlinearity, ppm of Full Scale
Typ 0.1 Hz to 10 Hz Voltage Noise, µV p-p
10 ppm
0.6 µV p-p
20 ppm
10
0.6
10.6
3763
20
0.55 µV p-p × √2
Total Resolution Error
Grand Total Error
0.778
20.778
5775
Rev. E | Page 10 of 16
Data Sheet
AD622
GAIN SELECTION
REFERENCE TERMINAL
The AD622 gain is resistor programmed by RG or, more
precisely, by whatever impedance appears between Pin 1 and
Pin 8. The AD622 is designed to offer gains as close as possible
to popular integer values using standard 1% resistors. Table 6
shows required values of RG for various gains. Note that for
G = 1, the RG pins are unconnected (RG = ∞). For any arbitrary
gain, RG can be calculated by using the formula
The reference terminal potential defines the zero output voltage
and is especially useful when the load does not share a precise
ground with the rest of the system. The reference terminal provides
a direct means of injecting a precise offset to the output, with an
allowable range of 2 V within the supply voltages. Parasitic
resistance should be kept to a minimum for optimum CMR.
50.5 k Ω
RG =
INPUT PROTECTION
G −1
The AD622 safely withstands an input current of 60 mA for
several hours at room temperature. This is true for all gains and
power on and off, which is useful if the signal source and amplifier
are powered separately. For longer time periods, the input
current should not exceed 6 mA.
To minimize gain error, avoid high parasitic resistance in series
with RG. To minimize gain drift, RG should have a low temperature
coefficient less than 10 ppm/°C for the best performance.
Table 6. Required Values of Gain Resistors
For input voltages beyond the supplies, a protection resistor should
be placed in series with each input to limit the current to 6 mA.
These can be the same resistors as those used in the RFI filter.
High values of resistance can impact the noise and AC CMRR
performance of the system. Low leakage diodes (such as the
BAV199) can be placed at the inputs to reduce the required
protection resistance.
Desired
Gain
Calculated
1% Std Table Value of RG, Ω Gain
2
5
10
20
33
40
50
65
100
200
500
1000
51.1 k
12.7 k
5.62 k
2.67 k
1.58 k
1.3 k
1.02 k
787
511
255
102
51.1
1.988
4.976
9.986
19.91
32.96
39.85
50.50
65.17
99.83
199.0
496.1
989.3
+SUPPLY
+IN
–IN
R
R
VOUT
AD622
REF
INPUT AND OUTPUT OFFSET VOLTAGE
The low errors of the AD622 are attributable to two sources:
input and output errors. The output error is divided by G when
referred to the input. In practice, the input errors dominate at
high gains and the output errors dominate at low gains. The
total VOS for a given gain is calculated as follows:
–SUPPLY
Figure 18. Diode Protection for Voltages Beyond Supply
Total Error RTI = input error + (output error/G)
Total Error RTO = (input error × G) + output error
Rev. E | Page 11 of 16
AD622
Data Sheet
RF INTERFERENCE
GROUND RETURNS FOR INPUT BIAS CURRENTS
RF rectification is often a problem when amplifiers are used in
applications where there are strong RF signals. The disturbance
may appear as a small dc offset voltage. High frequency signals
can be filtered with a low-pass, RC network placed at the input
of the instrumentation amplifier, as shown in Figure 19. In
addition, this RC input network also provides additional input
overload protection (see the Input Protection section).
Input bias currents are those currents necessary to bias the
input transistors of an amplifier. There must be a direct return
path for these currents; therefore, when amplifying floating
input sources such as transformers or ac-coupled sources, there
must be a dc path from each input to ground as shown in
Figure 20, Figure 21, and Figure 22. Refer to the Designer’s
Guide to Instrumentation Amplifiers (free from Analog Devices,
Inc.) for more information regarding in-amp applications.
+V
S
+V
S
+
0.1µF
+IN
10µF
–IN
2
1
7
C
1nF
C
R
4.02kΩ
R
G
6
V
AD622
OUT
V
OUT
C
D
R
G
R
AD622
8
3
5
47nF
4.02kΩ
REF
LOAD
4
–IN
+IN
REF
C
C
1nF
–V
S
TO POWER
SUPPLY
GROUND
0.1µF
10µF
+
–V
S
Figure 20. Ground Returns for Bias Currents with Transformer Coupled Inputs
Figure 19. RFI Suppression Circuit for AD622 Series In-Amps
+V
S
–IN
2
1
7
The filter limits the input signal bandwidth to the following
cutoff frequencies:
R
G
6
V
AD622
OUT
8
3
5
1
LOAD
4
FilterFreqDIFF
=
+IN
REF
2π R(2CD + CC )
–V
S
TO POWER
SUPPLY
GROUND
1
FilterFreqCM
=
2π RCC
Figure 21. Ground Returns for Bias Currents with Thermocouple Inputs
where CD ≥ 10CC.
+V
S
–IN
Figure 19 shows an example where the differential filter
frequency is approximately 400 Hz, and the common-mode
filter frequency is approximately 40 kHz. With this differential
filter in place and operating at gain of 1000, the typical dc offset
shift over a frequency range of 1 Hz to 20 MHz is less than 1.5 µV
RTI, and the RF signal rejection of the circuit is better than
71 dB. At a gain of 100, the dc offset shift is well below 1 mV
RTI, and RF rejection is greater than 70 dB.
2
1
7
R
G
6
V
AD622
OUT
8
3
5
LOAD
4
+IN
REF
100kΩ
100kΩ
–V
S
TO POWER
SUPPLY
GROUND
Figure 22. Ground Returns for Bias Currents with AC-Coupled Inputs
The input resistors should be selected to be high enough to
isolate the sensor from the CC and C D capacitors but low
enough not to influence system noise. Mismatch between
R × CC at the positive input and R × CC at the negative input
degrades the CMRR of the AD622. Therefore, the CC capacitors
should be high precision types such as NPO/COG ceramics.
The tolerance of the CD capacitor is less critical.
Rev. E | Page 12 of 16
Data Sheet
AD622
OUTLINE DIMENSIONS
0.400 (10.16)
0.365 (9.27)
0.355 (9.02)
8
1
5
4
0.280 (7.11)
0.250 (6.35)
0.240 (6.10)
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.100 (2.54)
BSC
0.060 (1.52)
MAX
0.195 (4.95)
0.130 (3.30)
0.115 (2.92)
0.210 (5.33)
MAX
0.015
(0.38)
MIN
0.150 (3.81)
0.130 (3.30)
0.115 (2.92)
0.015 (0.38)
GAUGE
0.014 (0.36)
0.010 (0.25)
0.008 (0.20)
PLANE
SEATING
PLANE
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
0.430 (10.92)
MAX
0.005 (0.13)
MIN
0.070 (1.78)
0.060 (1.52)
0.045 (1.14)
COMPLIANT TO JEDEC STANDARDS MS-001
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 23. 8-Lead Plastic Dual In-Line Package [PDIP]
Narrow Body
(N-8)
Dimensions shown in inches and (millimeters)
5.00 (0.1968)
4.80 (0.1890)
8
1
5
4
6.20 (0.2441)
5.80 (0.2284)
4.00 (0.1574)
3.80 (0.1497)
0.50 (0.0196)
0.25 (0.0099)
1.27 (0.0500)
BSC
45°
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
8°
0°
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
1.27 (0.0500)
0.40 (0.0157)
0.25 (0.0098)
0.17 (0.0067)
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MS-012-AA
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.
Figure 24. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
Rev. E | Page 13 of 16
AD622
Data Sheet
ORDERING GUIDE
Model1
AD622ANZ
Temperature Range
−40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
Package Description
8-Lead PDIP
Package Option
N-8
R-8
R-8
R-8
R-8
R-8
R-8
AD622AR
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
AD622AR-REEL
AD622AR-REEL7
AD622ARZ
AD622ARZ-RL
AD622ARZ-R7
1 Z = RoHS Compliant Part.
Rev. E | Page 14 of 16
Data Sheet
NOTES
AD622
Rev. E | Page 15 of 16
AD622
NOTES
Data Sheet
©1996–2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D00777-0-6/12(E)
Rev. E | Page 16 of 16
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