CONNECTION DIAGRAM
8-Lead Plastic Mini-DIP (N), Cerdip (Q)
and SOIC (R) Packages
–IN
RG
–VS
+IN
RG
+VS
OUTPUT
REF
1
2
3
4
8
7
6
5
AD620
TOP VIEW
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
Low Cost, Low Power
Instrumentation Amplifier
AD620
FEATURES
EASY TO USE
Gain Set with One External Resistor
(Gain Range 1 to 1000)
Wide Power Supply Range (62.3 V to 618 V)
Higher Performance than Three Op Amp IA Designs
Available in 8-Lead DIP and SOIC Packaging
Low Power, 1.3 mA max Supply Current
EXCELLENT DC PERFORMANCE (“B GRADE”)
50 mV max, Input Offset Voltage
0.6 mV/8C max, Input Offset Drift
1.0 nA max, Input Bias Current
100 dB min Common-Mode Rejection Ratio (G = 10)
LOW NOISE
9 nV/√Hz, @ 1 kHz, Input Voltage Noise
0.28 mV p-p Noise (0.1 Hz to 10 Hz)
EXCELLENT AC SPECIFICATIONS
120 kHz Bandwidth (G = 100)
15 ms Settling Time to 0.01%
APPLICATIONS
Weigh Scales
ECG and Medical Instrumentation
Transducer Interface
Data Acquisition Systems
Industrial Process Controls
Battery Powered and Portable Equipment
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., 1999
PRODUCT DESCRIPTION
The AD620 is a low cost, high accuracy instrumentation ampli-
fier that requires only one external resistor to set gains of 1 to
0 5 10 15 20
30,000
5,000
10,000
15,000
20,000
25,000
0
TOTAL ERROR, PPM OF FULL SCALE
SUPPLY CURRENT – mA
AD620A
R
G
3 OP-AMP
IN-AMP
(3 OP-07s)
Figure 1. Three Op Amp IA Designs vs. AD620
SOURCE RESISTANCE – V
100M10k1k 10M1M100k
10,000
0.1
100
1,000
10
1
RTI VOLTAGE NOISE
(0.1 – 10Hz) – mV p-p
TYPICAL STANDARD
BIPOLAR INPUT
IN-AMP
AD620 SUPERbETA
BIPOLAR INPUT
IN-AMP
G = 100
Figure 2. Total Voltage Noise vs. Source Resistance
1000. Furthermore, the AD620 features 8-lead SOIC and DIP
packaging that is smaller than discrete designs, and offers lower
power (only 1.3 mA max supply current), making it a good fit
for battery powered, portable (or remote) applications.
The AD620, with its high accuracy of 40 ppm maximum
nonlinearity, low offset voltage of 50 µV max and offset drift of
0.6 µV/°C max, is ideal for use in precision data acquisition
systems, such as weigh scales and transducer interfaces. Fur-
thermore, the low noise, low input bias current, and low power
of the AD620 make it well suited for medical applications such
as ECG and noninvasive blood pressure monitors.
The low input bias current of 1.0 nA max is made possible with
the use of Superβeta processing in the input stage. The AD620
works well as a preamplifier due to its low input voltage noise of
9 nV/√Hz at 1 kHz, 0.28 µV p-p in the 0.1 Hz to 10 Hz band,
0.1 pA/√Hz input current noise. Also, the AD620 is well suited
for multiplexed applications with its settling time of 15 µs to
0.01% and its cost is low enough to enable designs with one in-
amp per channel.
AD620–SPECIFICATIONS
(Typical @ +258C, V
S
=
6
15 V, and R
L
= 2 kV, unless otherwise noted)
AD620A AD620B AD620S
1
Model Conditions Min Typ Max Min Typ Max Min Typ Max Units
GAIN G = 1 + (49.4 k/R
G
)
Gain Range 1 10,000 1 10,000 1 10,000
Gain Error
2
V
OUT
= ±10 V
G = 1 0.03 0.10 0.01 0.02 0.03 0.10 %
G = 10 0.15 0.30 0.10 0.15 0.15 0.30 %
G = 100 0.15 0.30 0.10 0.15 0.15 0.30 %
G = 1000 0.40 0.70 0.35 0.50 0.40 0.70 %
Nonlinearity, V
OUT
= –10 V to +10 V,
G = 1–1000 R
L
= 10 kΩ10 40 10 40 10 40 ppm
G = 1–100 R
L
= 2 kΩ10 95 10 95 10 95 ppm
Gain vs. Temperature
G =1 10 10 10 ppm/°C
Gain >1
2
–50 –50 –50 ppm/°C
VOLTAGE OFFSET (Total RTI Error = V
OSI
+ V
OSO
/G)
Input Offset, V
OSI
V
S
= ±5 V to ±15 V 30 125 15 50 30 125 µV
Over Temperature V
S
= ±5 V to ±15 V 185 85 225 µV
Average TC V
S
= ±5 V to ±15 V 0.3 1.0 0.1 0.6 0.3 1.0 µV/°C
Output Offset, V
OSO
V
S
= ±15 V 400 1000 200 500 400 1000 µV
V
S
= ±5 V 1500 750 1500 µV
Over Temperature V
S
= ±5 V to ±15 V 2000 1000 2000 µV
Average TC V
S
= ±5 V to ±15 V 5.0 15 2.5 7.0 5.0 15 µV/°C
Offset Referred to the
Input vs.
Supply (PSR) V
S
= ±2.3 V to ±18 V
G = 1 80 100 80 100 80 100 dB
G = 10 95 120 100 120 95 120 dB
G = 100 110 140 120 140 110 140 dB
G = 1000 110 140 120 140 110 140 dB
INPUT CURRENT
Input Bias Current 0.5 2.0 0.5 1.0 0.5 2 nA
Over Temperature 2.5 1.5 4 nA
Average TC 3.0 3.0 8.0 pA/°C
Input Offset Current 0.3 1.0 0.3 0.5 0.3 1.0 nA
Over Temperature 1.5 0.75 2.0 nA
Average TC 1.5 1.5 8.0 pA/°C
INPUT
Input Impedance
Differential 10i210i210i2GΩipF
Common-Mode 10i210i210i2GΩipF
Input Voltage Range
3
V
S
= ±2.3 V to ±5 V –V
S
+ 1.9 +V
S
– 1.2 –V
S
+ 1.9 +V
S
– 1.2 –V
S
+ 1.9 +V
S
– 1.2 V
Over Temperature –V
S
+ 2.1 +V
S
– 1.3 –V
S
+ 2.1 +V
S
– 1.3 –V
S
+ 2.1 +V
S
– 1.3 V
V
S
= ±5 V to ±18 V –V
S
+ 1.9 +V
S
– 1.4 –V
S
+ 1.9 +V
S
– 1.4 –V
S
+ 1.9 +V
S
– 1.4 V
Over Temperature –V
S
+ 2.1 +V
S
– 1.4 –V
S
+ 2.1 +V
S
– 1.4 –V
S
+ 2.3 +V
S
– 1.4 V
Common-Mode Rejection
Ratio DC to 60 Hz with
I kΩ Source Imbalance V
CM
= 0 V to ±10 V
G = 1 7390 8090 7390 dB
G = 10 93 110 100 110 93 110 dB
G = 100 110 130 120 130 110 130 dB
G = 1000 110 130 120 130 110 130 dB
OUTPUT
Output Swing R
L
= 10 kΩ,
V
S
= ±2.3 V to ±5 V –V
S
+ 1.1 +V
S
– 1.2 –V
S
+ 1.1 +V
S
– 1.2 –V
S
+ 1.1 +V
S
– 1.2 V
Over Temperature –V
S
+ 1.4 +V
S
– 1.3 –V
S
+ 1.4 +V
S
– 1.3 –V
S
+ 1.6 +V
S
– 1.3 V
V
S
= ±5 V to ±18 V –V
S
+ 1.2 +V
S
– 1.4 –V
S
+ 1.2 +V
S
– 1.4 –V
S
+ 1.2 +V
S
– 1.4 V
Over Temperature –V
S
+ 1.6 +V
S
– 1.5 –V
S
+ 1.6 +V
S
– 1.5 –V
S
+ 2.3 +V
S
– 1.5 V
Short Current Circuit ±18 ±18 ±18 mA
REV. E
–2–
AD620
AD620A AD620B AD620S
1
Model Conditions Min Typ Max Min Typ Max Min Typ Max Units
DYNAMIC RESPONSE
Small Signal –3 dB Bandwidth
G = 1 1000 1000 1000 kHz
G = 10 800 800 800 kHz
G = 100 120 120 120 kHz
G = 1000 12 12 12 kHz
Slew Rate 0.75 1.2 0.75 1.2 0.75 1.2 V/µs
Settling Time to 0.01% 10 V Step
G = 1–100 15 15 15 µs
G = 1000 150 150 150 µs
NOISE
Voltage Noise, 1 kHz
Total RTI Noise =(e
2
ni )+(eno /G)
2
Input, Voltage Noise, e
ni
913 913 913 nV/√Hz
Output, Voltage Noise, e
no
72 100 72 100 72 100 nV/√Hz
RTI, 0.1 Hz to 10 Hz
G = 1 3.0 3.0 6.0 3.0 6.0 µV p-p
G = 10 0.55 0.55 0.8 0.55 0.8 µV p-p
G = 100–1000 0.28 0.28 0.4 0.28 0.4 µV p-p
Current Noise f = 1 kHz 100 100 100 fA/√Hz
0.1 Hz to 10 Hz 10 10 10 pA p-p
REFERENCE INPUT
R
IN
20 20 20 kΩ
I
IN
V
IN+
, V
REF
= 0 +50 +60 +50 +60 +50 +60 µA
Voltage Range –V
S
+ 1.6 +V
S
– 1.6 –V
S
+ 1.6 +V
S
– 1.6 –V
S
+ 1.6 +V
S
– 1.6 V
Gain to Output 1 ± 0.0001 1 ± 0.0001 1 ± 0.0001
POWER SUPPLY
Operating Range
4
±2.3 ±18 ±2.3 ±18 ±2.3 ±18 V
Quiescent Current V
S
= ±2.3 V to ±18 V 0.9 1.3 0.9 1.3 0.9 1.3 mA
Over Temperature 1.1 1.6 1.1 1.6 1.1 1.6 mA
TEMPERATURE RANGE
For Specified Performance –40 to +85 –40 to +85 –55 to +125 °C
NOTES
1
See Analog Devices military data sheet for 883B tested specifications.
2
Does not include effects of external resistor R
G
.
3
One input grounded. G = 1.
4
This is defined as the same supply range which is used to specify PSR.
Specifications subject to change without notice.
REV. E –3–
AD620
REV. E
–4–
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
ABSOLUTE MAXIMUM RATINGS
1
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
AD620 (A, B) . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
AD620 (S) . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C
Lead Temperature Range
(Soldering 10 seconds) . . . . . . . . . . . . . . . . . . . . . . . +300°C
ORDERING GUIDE
Model Temperature Ranges Package Options*
AD620AN –40°C to +85°C N-8
AD620BN –40°C to +85°C N-8
AD620AR –40°C to +85°C SO-8
AD620AR-REEL –40°C to +85°C 13" REEL
AD620AR-REEL7 –40°C to +85°C 7" REEL
AD620BR –40°C to +85°C SO-8
AD620BR-REEL –40°C to +85°C 13" REEL
AD620BR-REEL7 –40°C to +85°C 7" REEL
AD620ACHIPS –40°C to +85°C Die Form
AD620SQ/883B –55°C to +125°C Q-8
*N = Plastic DIP; Q = Cerdip; SO = Small Outline.
METALIZATION PHOTOGRAPH
Dimensions shown in inches and (mm).
Contact factory for latest dimensions.
+VSOUTPUT
REFERENCE
+IN
–VS
–IN
*FOR CHIP APPLICATIONS: THE PADS 1RG AND 8RG MUST BE CONNECTED IN PARALLEL
TO THE EXTERNAL GAIN REGISTER RG. DO NOT CONNECT THEM IN SERIES TO RG. FOR
UNITY GAIN APPLICATIONS WHERE RG IS NOT REQUIRED, THE PADS 1RG MAY SIMPLY
BE BONDED TOGETHER, AS WELL AS THE PADS 8RG.
4
5
67
8
8
RG*
1
123
RG*0.125
(3.180)
0.0708
(1.799)
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD620 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
