Analog Devices AD620 g Datasheet

Low Cost Low Power

FEATURES

Easy to use

Gain set with one external resistor

(Gain range 1 to 10,000)
Wide power supply range (±2.3 V to ±18 V)
Higher performance than 3 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 µV max, input offset voltage

0.6 µV/°C 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 µV p-p noise (0.1 Hz to 10 Hz)

Excellent ac specifications

120 kHz bandwidth (G = 100)
15 µs 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

30,000

Instrumentation Amplifier

AD620

CONNECTION DIAGRAM

1

R

G

2

–IN

3

+IN

4

–V

S

AD620

TOP VIEW

Figure 1. 8-Lead PDIP (N), CERDIP (Q), and SOIC (R) Packages

PRODUCT DESCRIPTION

The AD620 is a low cost, high accuracy instrumentation
amplifier that requires only one external resistor to set gains of
1 to 10,000. 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.
Furthermore, 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,
and 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.

10,000

8

7

6

5

R

G

+V

S

OUTPUT

REF

00775-0-001

25,000

20,000

15,000

AD620A

10,000

R

G

5,000

TOTAL ERROR, PPM OF FULL SCALE

0

0 5 10 15 20

SUPPLY CURRENT (mA)

3 OP AMP
IN-AMP
(3 OP-07s)

00775-0-002

Figure 2. Three Op Amp IA Designs vs. AD620

Rev. G

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.

RTI VOLTAGE NOISE

1,000

100

V p-p)

µ

(0.1 – 10Hz) (

10

1

0.1

TYPICAL STANDARD
BIPOLAR INPUT
IN-AMP

G = 100

SOURCE RESISTANCE (Ω)

AD620 SUPERβETA
BIPOLAR INPUT
IN-AMP

Figure 3. Total Voltage Noise vs. Source Resistance

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

100M10k1k 10M1M100k

00775-0-003

AD620

TABLE OF CONTENTS

Specifications .....................................................................................3

Input Protection..........................................................................16

Absolute Maximum Ratings ............................................................5

ESD Caution ..................................................................................5

Typical Performance Characteristics..............................................7

Theory of Operation.......................................................................13

Gain Selection..............................................................................16

Input and Output Offset Voltage ..............................................16

Reference Terminal.....................................................................16

REVISION HISTORY

12/04—Rev. F to Rev. G

Updated Format..................................................................Universal

Change to Features............................................................................1

Change to Product Description.......................................................1

Changes to Specifications.................................................................3

Added Metallization Photograph....................................................4

Replaced Figure 4-Figure 6..............................................................6

Replaced Figure 15............................................................................7

Replaced Figure 33..........................................................................10

Replaced Figure 34 and Figure 35.................................................10

Replaced Figure 37..........................................................................10

Changes to Table 3 ..........................................................................13

Changes to Figure 41 and Figure 42 .............................................14

Changes to Figure 43 ......................................................................15

Change to Figure 44........................................................................17

Changes to Input Protection section ............................................15

Deleted Figure 9...............................................................................15

Changes to RF Interference section..............................................15

Edit to Ground Returns for Input Bias Currents section...........17

Added AD620CHIPS to Ordering Guide....................................19

RF Interference............................................................................16

Common-Mode Rejection.........................................................17

Grounding....................................................................................17

Ground Returns for Input Bias Currents.................................18

Outline Dimensions........................................................................19

Ordering Guide...........................................................................20

7/03—Data Sheet changed from REV. E to REV. F

Edit to FEATURES............................................................................1

Changes to SPECIFICATIONS.......................................................2

Removed AD620CHIPS from ORDERING GUIDE................... 4

Removed METALLIZATION PHOTOGRAPH...........................4

Replaced TPCs 1–3 ...........................................................................5

Replaced TPC 12...............................................................................6

Replaced TPC 30...............................................................................9

Replaced TPCs 31 and 32...............................................................10

Replaced Figure 4............................................................................10

Changes to Table I...........................................................................11

Changes to Figures 6 and 7............................................................12

Changes to Figure 8 ........................................................................13

Edited INPUT PROTECTION section........................................13

Added new Figure 9........................................................................13

Changes to RF INTERFACE section............................................14

Edit to GROUND RETURNS FOR INPUT BIAS CURRENTS

section...............................................................................................15

Updated OUTLINE DIMENSIONS.............................................16

Rev. G | Page 2 of 20

AD620

SPECIFICATIONS

Typical @ 25°C, VS = ±15 V, and RL = 2 kΩ, unless otherwise noted.

Table 1.

AD620A AD620B

Parameter Conditions

Min Typ Max Min Typ Max Min Typ Max Unit

AD620S1

GAIN G = 1 + (49.4 kΩ/RG)

Gain Range 1 10,000 1 10,000 1 10,000

V

Gain Error2

= ±10 V

OUT

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

= −10 V to +10 V

OUT

G = 1–1000 RL = 10 kΩ 10 40 10 40 10 40 ppm

G = 1–100 RL = 2 kΩ 10 95 10 95 10 95 ppm
Gain vs. Temperature

G = 1 10 10 10 ppm/°C
Gain >12 −50 −50 −50 ppm/°C
VOLTAGE OFFSET (Total RTI Error = V

Input Offset, V

VS = ±5 V

OSI

+ V

/G)

OSI

OSO

30 125 15 50 30 125 µV

to ± 15 V

Overtemperature VS = ±5 V

185 85 225 µV

to ± 15 V

Average TC VS = ±5 V

0.3 1.0 0.1 0.6 0.3 1.0 µV/°C

to ± 15 V
Output Offset, V
V

Overtemperature VS = ±5 V

VS = ±15 V 400 1000 200 500 400 1000 µV

OSO

= ± 5 V 1500 750 1500 µV

S

2000 1000 2000 µV

to ± 15 V

Average TC VS = ±5 V

5.0 15 2.5 7.0 5.0 15 µV/°C

to ± 15 V
Offset Referred to the
Input vs. Supply (PSR) VS = ±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

Overtemperature 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

Overtemperature 1.5 0.75 2.0 nA
Average TC 1.5 1.5 8.0 pA/°C

INPUT

Input Impedance

Differential 10||2 10||2 10||2 GΩ_pF
Common-Mode 10||2 10||2 10||2 GΩ_pF

Input Voltage Range3

= ±2.3 V

S

−VS + 1.9 +VS − 1.2 −VS + 1.9 +VS − 1.2 −VS + 1.9 +VS − 1.2 V

V

to ±5 V

Overtemperature −VS + 2.1 +VS − 1.3 −VS + 2.1 +VS − 1.3 −VS + 2.1 +VS − 1.3 V

V

= ± 5 V

S

−VS + 1.9 +VS − 1.4 −VS + 1.9 +VS − 1.4 −VS + 1.9 +VS − 1.4 V

to ±18 V

Overtemperature −VS + 2.1 +VS − 1.4 −VS + 2.1 +VS + 2.1 −VS + 2.3 +VS − 1.4 V

Rev. G | Page 3 of 20

AD620

AD620A AD620B

Parameter Conditions

Min Typ Max Min Typ Max Min Typ Max Unit

AD620S

1

Common-Mode Rejection

Ratio DC to 60 Hz with
1 kΩ Source Imbalance VCM = 0 V to ± 10 V

G = 1 73 90 80 90 73 90 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 RL = 10 kΩ

V

Overtemperature −VS + 1.4 +VS − 1.3

= ±2.3 V

S

to ± 5 V

VS = ±5 V

−VS +

+VS − 1.2

1.1

−VS + 1.2 +VS − 1.4

−VS + 1.1

−VS + 1.4

−VS + 1.2

+VS − 1.2 −VS + 1.1 +VS − 1.2 V

+VS − 1.3 −VS + 1.6 +VS − 1.3 V
+VS − 1.4 −VS + 1.2 +VS − 1.4 V

to ± 18 V
Overtemperature −VS + 1.6 +VS – 1.5

−VS + 1.6

+VS – 1.5 –VS + 2.3 +VS – 1.5 V

Short Circuit Current ±18 ±18 ±18 mA

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

Input, Voltage Noise, eni
Output, Voltage Noise, e

2

ni

9 13 9 13 9 13 nV/√Hz
72 100 72 100 72 100 nV/√Hz

no

2

)/()( GeeNoiseRTITotal

+=

no

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

RIN 20 20 20 kΩ
IIN V

, V

= 0 50 60 50 60 50 60 µA

IN+

REF

Voltage Range −VS + 1.6 +VS − 1.6 −VS + 1.6 +VS − 1.6 −VS + 1.6 +VS − 1.6 V
Gain to Output 1 ± 0.0001 1 ± 0.0001 1 ± 0.0001

POWER SUPPLY

Operating Range4
Quiescent Current VS = ±2.3 V

±2.3 ±18 ±2.3 ±18 ±2.3 ±18 V

0.9 1.3 0.9 1.3 0.9 1.3 mA

to ±18 V

Overtemperature 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

1

See Analog Devices military data sheet for 883B tested specifications.

2

Does not include effects of external resistor RG.

3

One input grounded. G = 1.

4

This is defined as the same supply range that is used to specify PSR.

Rev. G | Page 4 of 20

AD620

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage ±18 V
Internal Power Dissipation1 650 mW
Input Voltage (Common-Mode) ±VS
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

1

Specification is for device in free air:

8-Lead Plastic Package: θ
8-Lead CERDIP Package: θ
8-Lead SOIC Package: θ

= 95°C

JA

= 110°C

JA

= 155°C

JA

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 condition s 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.

ESD 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 this product 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.

Rev. G | Page 5 of 20

AD620

00775-0-004

Figure 4. Metallization Photograph.

Dimensions shown in inches and (mm).

Contact sales for latest dimensions.

Rev. G | Page 6 of 20