Analog Devices AD8225 a Datasheet

Precision Gain of 5

Instrumentation Amplifier

AD8225

FEATURES
No External Components Required
Highly Stable, Factory Trimmed Gain of 5
Low Power, 1.2 mA Max Supply Current
Wide Power Supply Range (1.7 V to 18 V)
Single- and Dual-Supply Operation
Excellent Dynamic Performance

High CMRR

86 dB Min @ DC
80 dB Min to 10 kHz

Wide Bandwidth

900 kHz
4 V to 36 V Single Supply

High Slew Rate

5 V/s Min

Outstanding DC Precision

Low Gain Drift

5 ppm/C Max

Low Input Offset Voltage

150 V Max

Low Offset Drift

2 V/C Max

Low Input Bias Current

1.2 nA Max

APPLICATIONS
Patient Monitors
Current Transmitters
Multiplexed Systems
4 to 20 mA Converters
Bridge Transducers
Sensor Signal Conditioning

FUNCTIONAL BLOCK DIAGRAM

NC

–IN

+IN

–V

140

130

120

110

100

90

HIGH PERFORMANCE IN AMP

80

CMRR – dB

70

60

50

40

30

1 100k10

@ GAIN OF 5

AD8225

1

2

3

4

S

NC = NO CONNECT

100 1k 10k

FREQUENCY – Hz

8

NC

7

+V

S

6

V

OUT

5

REF

Figure 1. Typical CMRR vs. Frequency

AD8225

GENERAL DESCRIPTION

The AD8225 is an instrumentation amplifier with a fixed gain
of 5, which sets new standards of performance. The superior
CMRR of the AD8225 enables rejection of high frequency
common-mode voltage (80 dB Min @ 10 kHz). As a result,
higher ambient levels of noise from utility lines, industrial
equipment, and other radiating sources are rejected. Extended
CMV range enables the AD8225 to extract low level differential
signals in the presence of high common-mode dc voltage levels
even at low supply voltages.

Ambient electrical noise from utility lines is present at 60 Hz
and harmonic frequencies. Power systems operating at 400 Hz
create high noise environments in aircraft instrument clusters.
Good CMRR performance over frequency is necessary if power
system generated noise is to be rejected. The dc to 10 kHz

REV. A

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. 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 companies.

CMRR performance of the AD8225 rejects noise from utility
systems, motors, and repair equipment on factory floors, switch­ing power supplies, and medical equipment.

Low input bias currents combined with a high slew rate of 5 V/µs
make the AD8225 ideally suited for multiplexed applications.

The AD8225 provides excellent dc precision, with maximum
input offset voltage of 150 µV and drift of 2 µV/°C. Gain drift is
5ppm/°C or less.

Operating on either single or dual supplies, the fixed gain of 5
and wide input common-mode voltage range make the AD8225
well suited for patient monitoring applications.

The AD8225 is packaged in an 8-lead SOIC package and is
specified over the standard industrial temperature range, –40°C
to +85°C.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2003 Analog Devices, Inc. All rights reserved.

AD8225–SPECIFICATIONS

(TA = 25C, VS = 15 V, RL = 2 k, unless otherwise noted.)

Parameter Conditions Min Typ Max Unit

GAIN

Gain 5V/V
Gain Error –0.1 +0.05 +0.1 %
Nonlinearity 2 10 ±ppm
vs. Temperature 1 5 ±ppm/°C

OFFSET VOLTAGE (RTI)

Offset Voltage 50 150 ±µV
vs. Temperature 0.3 2 ±µV/°C
vs. Supply (PSRR) 90 100 dB

INPUT

Input Operating Impedance

储

Differential 10
Common Mode 10

Input Voltage Range –V

+ 1.6 +VS – 1.0 V

S

2GΩ储pF

储

2GΩ储pF

(Common-Mode)

vs. Temperature –V

+ 2.2 +VS – 1.2 V

S

Input Bias Current 0.5 1.2 nA

vs. Temperature 3 pA/°C

Input Offset Current 0.15 0.5 nA

vs. Temperature 1.5 pA/°C

Common-Mode Rejection Ratio 86 94 dB

= T

T

A

MIN

to T

MAX

83 dB

f = 10 kHz* 80 dB

OUTPUT

Operating Voltage Range RL = 2 kΩ –VS + 1.4 +VS – 1.4 V

vs. Temperature –V

Operating Voltage Range R

= 10 kΩ –VS + 1.0 +VS – 1.1 V

L

vs. Temperature –V

+ 1.5 +VS – 1.6 V

S

+ 1.2 +VS – 1.0 V

S

Short Circuit Current 18 mA

DYNAMIC RESPONSE

Small Signal –3 dB Bandwidth 900 kHz
Full Power Bandwidth V

= 20 V p-p 75 kHz

OUT

Settling Time (0.01%) 10 V Step 3.4 µs
Settling Time (0.001%) 10 V Step 4.8 µs
Slew Rate 5 V/µs

NOISE (RTI)

Voltage 0.1 Hz to 10 Hz 1.5 µV p-p

Spectral Density, 1 kHz 45 nV/√Hz

Current 0.1 Hz to 10 Hz 4 pA p-p

Spectral Density, 1 kHz 50 fA/√Hz

REFERENCE INPUT

R

IN

I

IN

Voltage Range –V

V

, V

IN+

= 0 18 kΩ

REF

60 µA

+ 1.4 +VS – 1.4 V

S

Gain to Output 0.999 1 1.001

POWER SUPPLY

Operating Range 1.7 18 ±V
Quiescent Current 1.05 1.2 mA

TEMPERATURE RANGE

For Specified Performance –40 +85 °C

*Pin 1 connected to Pin 4. See Applications section.

Specifications subject to change without notice.

REV. A–2–

AD8225

SPECIFICATIONS

(TA = 25C, VS = 5 V, RL = 2 k, unless otherwise noted.)

Parameter Conditions Min Typ Max Unit

GAIN

Gain 5V/V
Gain Error –0.1 +0.05 +0.1 %
Nonlinearity 2 10 ±ppm
vs. Temperature 1 5 ±ppm/°C

VOLTAGE OFFSET (RTI)

Offset Voltage 125 325 ±µV
vs. Temperature 2 ±µV/°C
vs. Supply 90 100 dB

INPUT

Input Operating Impedance

Differential 10
Common-Mode 10

Input Operating Voltage Range –V

vs. Temperature –V

+ 1.6 +VS – 1.0 V

S

+ 2.1 +VS – 1.5 V

S

储

2GΩ储pF

储

2GΩ储pF

Input Bias Current 0.5 1.2 nA

vs. Temperature 3 pA/°C

Input Offset Current 0.15 0.5 nA

vs. Temperature 1.5 pA/°C

Common-Mode Rejection Ratio 86 94 dB

= T

T

A

MIN

to T

MAX

83 dB

f = 10 kHz* 80 dB

OUTPUT

Operating Voltage Range RL = 2 kΩ –VS + 0.9 +VS – 1.0 V

vs. Temperature –V

Operating Voltage Range R

= 10 kΩ –VS + 0.8 +VS – 1.0 V

L

vs. Temperature –V

+ 1.0 +VS – 1.2 V

S

+ 0.9 +VS – 1.0 V

S

Short Circuit Current 18 mA

DYNAMIC RESPONSE

Small Signal –3 dB Bandwidth 900 kHz
Full Power Bandwidth V

= 7.8 V p-p 170 kHz

OUT

Settling Time (0.01%) 7 V Step 3 µs
Settling Time (0.001%) 7 V Step 4.3 µs
Slew Rate 5 V/µs

NOISE (RTI)

Voltage 0.1 Hz to 10 Hz 1.5 µV p-p

Spectral Density, 1 kHz 45 nV/√Hz

Current 0.1 Hz to 10 Hz 4 pA p-p

Spectral Density, 1 kHz 50 fA/√Hz

REFERENCE INPUT

R

IN

I

IN

V

, V

INT

= 0 60 µA

REF

Voltage Range –V

+ 0.9 +VS – 1.0 V

S

18 kΩ

Gain to Output 0.999 1 1.001

POWER SUPPLY

Operating Range 1.7 18 ±V
Quiescent Current 1.05 1.2 mA

TEMPERATURE RANGE

For Specified Performance –40 +85 °C

*Pin 1 connected to Pin 4. See Applications section.

Specifications subject to change without notice.

REV. A

–3–

AD8225

SPECIFICATIONS

(TA = 25C, VS = 5 V, RL = 2 k, unless otherwise noted.)

Parameter Conditions Min Typ Max Unit

GAIN

Gain 5V/V
Gain Error –0.1 +0.05 +0.1 %
Nonlinearity 2 10 ±ppm
vs. Temperature 1 5 ±ppm/°C

OFFSET VOLTAGE (RTI)

Offset Voltage 150 375 ±µV
vs. Temperature 2 ±µV/°C
vs. Supply 90 100 dB

INPUT

Input Operating Impedance

Differential 10
Common Mode 10

Input Voltage Range 1.6 V

储

2GΩ储pF

储

2GΩ储pF

– 1.05 V

S

(Common-Mode)

vs. Temperature 1.7 V

– 1.0 V

S

Input Bias Current 0.5 1.2 nA

vs. Temperature 3 pA/°C

Input Offset Current 0.15 0.5 nA

vs. Temperature 1.5 pA/°C

Common-Mode Rejection Ratio 86 94 dB

= T

T

A

MIN

to T

MAX

83 dB

f = 10 kHz* 80 dB

OUTPUT

Operating Voltage Range RL = 2 kΩ 0.8 VS – 1.05 V

vs. Temperature 0.9 V

Operating Voltage Range R

= 10 kΩ 0.8 VS – 1.0 V

L

vs. Temperature 0.9 V

– 1.2 V

S

– 1.0 V

S

Short Circuit Current 18 mA

DYNAMIC RESPONSE

Small Signal –3 dB Bandwidth 900 kHz
Full Power Bandwidth V

= 3.2 V p-p 420 kHz

OUT

Settling Time (0.01%) 2 V Step 3.3 µs
Settling Time (0.001%) 2 V Step 5.1 µs
Slew Rate 5 V/µs

NOISE (RTI)

Voltage 0.1 Hz to 10 Hz 1.5 µV p-p

Spectral Density, 1 kHz 45 nV/√Hz

Current 0.1 Hz to 10 Hz 4 pA p-p

Spectral Density, 1 kHz 50 fA/√Hz

REFERENCE INPUT

R

IN

I

IN

Voltage Range 0.4 V

18 kΩ
60 µA

– 0.9 V

S

Gain to Output 0.999 1 1.001

POWER SUPPLY

Operating Range 3.4 36 V
Quiescent Current 1.05 1.2 mA

TEMPERATURE RANGE

For Specified Performance –40 +85 °C

*Pin 1 connected to Pin 4. See Applications section.

Specifications subject to change without notice.

REV. A–4–

AD8225

AMBIENT TEMPERATURE – C

1.5

1.0

0

–5080–40

POWER DISSIPATION – W

–30

–20

–10 0 10 203040506070

0.5

90

TJ = 150 C

8-LEAD SOIC PACKAGE

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 18 V

Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . 650 mW

Input Voltage (Common-Mode) . . . . . . . . . . . . . . . . . . . . ±V

S

Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . ±25 V

Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite

Storage Temperature . . . . . . . . . . . . . . . . . . –65ºC to +125ºC

Operating Temperature Range . . . . . . . . . . . –40ºC to +85ºC

Lead Temperature Range (10 sec Soldering) . . . . . . . . . 300ºC

*Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent damage to the device. This is a stress rating only and 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.

PIN FUNCTION DESCRIPTIONS

Pin Number Mnemonic Function

1NCMay be Connected to Pin 4 to

Balance C

IN

2 –IN Inverting Input

3 +IN Noninverting Input

4 –V

S

Negative Supply Voltage

5 REF Connect to Desired Output

CMV

6V

7+V

OUT

S

Output

Positive Supply Voltage

8NC

Figure 2. Maximum Power Dissipation vs. Temperature

ORDERING GUIDE

Model Temperature Range Package Description Package Options

AD8225AR –40ºC to +85ºC 8-Lead SOIC RN-8
AD8225AR-REEL –40ºC to +85ºC 8-Lead SOIC 13" REEL
AD8225AR-REEL7 –40ºC to +85ºC 8-Lead SOIC 7" REEL
AD8225-EVAL Evaluation Board RN-8

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
AD8225 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. A

–5–