Analog Devices AD8230 Datasheet

16 V Rail-to-Rail, Zero-Drift,

FEATURES

Resistor programmable gain range: 101 to 1000
Supply voltage range: ±4 V to ±8 V, +8 V to +16 V
Rail-to-rail input and output
Maintains performance over −40°C to +125°C

EXCELLENT AC AND DC PERFORMANCE

110 dB minimum CMR @ 60 Hz, G = 10 to 1000
10 µV max offset voltage (RTI, ±5 V)
50 nV/°C max offset drift
20 ppm max gain nonlinearity

APPLICATIONS

Pressure measurements
Temperature measurements
Strain measurements
Automotive diagnostics

GENERAL DESCRIPTION

The AD8230 is a low drift, differential sampling, precision
instrumentation amplifier. Auto-zeroing reduces offset voltage
drift to less than 50 nV/°C. The AD8230 is well-suited for
thermocouple and bridge transducer applications. The
AD8230’s high CMR of 110 dB (min) rejects line noise in
measurements where the sensor is far from the instrumentation.
The 16 V rail-to-rail, common-mode input range is useful for
noisy environments where ground potentials vary by several
volts. Low frequency noise is kept to a minimal 3 µV p-p
making the AD8230 perfect for applications requiring the
utmost dc precision. Moreover, the AD8230 maintains its high
performance over the extended industrial temperature range of

−40°C to +125°C.

Two external resistors are used to program the gain. By using
matched external resistors, the gain stability of the AD8230 is
much higher than instrumentation amplifiers that use a single
resistor to set the gain. In addition to allowing users to program
the gain between 10
offset voltage.

1

and 1000, users may adjust the output

Precision Instrumentation Amplifier

AD8230

2.0

1.5

1.0

0.5

0

–0.5

–1.0

OFFSET VOLTAGE (µV RTI)

–1.5

–2.0

TEMPERATURE (°C)

Figure 1. Relative Offset Voltage vs. Temperature

+5V

–5V

0.1µF

4

TYPE K THERMOCOUPLE

Figure 2. Thermocouple Measurement

AD8230

5

3

0.1µF

2

1

7

6

34.8kΩ

284Ω

V

8

OUT

The AD8230 is versatile yet simple to use. Its auto-zeroing
topology significantly minimizes the input and output
transients typical of commutating or chopper instrumentation
amplifiers. The AD8230 operates on ±4 V to ±8 V (+8 V to +16 V)
supplies and is available in an 8-lead SOIC.

1

The AD8230 can be programmed for a gain as low as 2, but the maximum

input voltage is limited to approximately 750 mV.

150–50 –30 –10 10 30 50 70 90 110 130

05063-002

05063-107

Rev. 0

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: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8230

TABLE OF CONTENTS

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

Input Voltage Range ................................................................... 11

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

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

Typical Performance Characteristics............................................. 6

Theory of Operation ...................................................................... 10

Setting the Gain.......................................................................... 10

Level-Shifting the Output.......................................................... 11

Source Impedance and Input Settling Time ........................... 11

REVISION HISTORY

10/04—Revision 0: Initial Version

Input Protection ......................................................................... 11

Power Supply Bypassing ............................................................ 11

Power Supply Bypassing for Multiple Channel Systems ....... 11

Layout .......................................................................................... 12

Applications ................................................................................ 12

Outline Dimensions....................................................................... 13

Ordering Guide .......................................................................... 13

Rev. 0 | Page 2 of 16

AD8230

SPECIFICATIONS

VS = ±5 V, V

Table 1.

Parameter Conditions Min Typ Max Unit

VOLTAGE OFFSET

RTI Offset, V
Offset Drift

COMMON-MODE REJECTION (CMR)

CMR to 60 Hz with 1 kΩ Source Imbalance VCM = −5 V to +5 V 110 120 dB

VOLTAGE OFFSET RTI vs. SUPPLY (PSR)

G = 2 120 120 dB
G = 202 120 140 dB

GAIN G = 2(1 + RF/RG)

Gain Range 10
Gain Error

G = 2 0.01 %
G = 10 0.01 %
G = 100 0.01 %
G = 1000 0.02 %

Gain Nonlinearity 20 ppm

INPUT

Input Common-Mode Operating Voltage Range −V
Over Temperature T = −40°C to +125°C −V
Input Differential Operating Voltage Range 750 mV
Average Input Offset Current

OUTPUT

Output Swing −VS + 0.1 +VS − 0.2 V
Over Temperature T = −40°C to +125°C −VS + 0.1 +VS − 0.2 V
Short-Circuit Current 15 mA

REFERENCE INPUT

Voltage Range −1 +1 V

NOISE

Voltage Noise Density, 1 kHz, RTI V

Voltage Noise f = 0.1 Hz to 10 Hz 3 µV p-p
SLEW RATE VIN = 500 mV, G = 10 2 V/µs
INTERNAL SAMPLE RATE 6 kHz
POWER SUPPLY

Operating Range (Dual Supplies) ±4 ±8 V

Operating Range (Single Supply) +8 +16 V

Quiescent Current T = −40°C to +125°C 2.7 3.5 mA
TEMPERATURE RANGE

Specified Performance −40 +125 °C

= 0 V, RF = 100 kΩ, RG = 1 kΩ (@ TA = 25°C, G = 202, RL = 10 kΩ, unless otherwise noted).

REF

V

OSI

2

= V

+IN

V

+IN

T

A

= 0 V 10 µV

−IN

= V

= 0 V,

−IN

50 nV/°C

= −40°C to +125°C

1

S

S

VCM = 0V 33 pA

, V

, V

IN+

= 0 240 nV/√Hz

IN−

REF

1000 V/V

+V
+V

S

S

V
V

1

The AD8230 can operate as low as G = 2. However, since the differential input range is limited to approximately 750 mV, the AD8230 configured at G < 10 does not

make use of the full output voltage range.

2

Differential source resistance less than 10 kΩ does not result in voltage offset due to input bias current or mismatched series resistors.

Rev. 0 | Page 3 of 16

AD8230

VS = ±8 V, V

Table 2.

Parameter Conditions Min Typ Max Unit

VOLTAGE OFFSET

RTI Offset, V
Offset Drift

COMMON-MODE REJECTION (CMR)

CMR to 60 Hz with 1 kΩ Source Imbalance VCM = −8 V to +8 V 110 120 dB

VOLTAGE OFFSET RTI vs. SUPPLY (PSR)

G = 2 120 120 dB
G = 202 120 140 dB

GAIN G = 2(1 + RF/RG)

Gain Range 10
Gain Error

G = 2 0.01 %
G = 10 0.01 %
G = 100 0.01 %
G = 1000 0.02 %

Gain Nonlinearity 20 ppm

INPUT

Input Common-Mode Operating Voltage Range −V
Over Temperature T = −40°C to +125°C −V
Input Differential Operating Voltage Range 750 mV
Average Input Offset Current

OUTPUT

Output Swing −VS + 0.1 +VS − 0.2 V
Over Temperature T = −40°C to +125°C −VS + 0.1 +VS − 0.4 V
Short-Circuit Current 15 mA

REFERENCE INPUT

Voltage Range −1 +1 V

NOISE

Voltage Noise Density, 1 kHz, RTI V

Voltage Noise f = 0.1 Hz to 10 Hz 3 µV p-p
SLEW RATE VIN = 500 mV, G = 10 2 V/µs
INTERNAL SAMPLE RATE 6 kHz
POWER SUPPLY

Operating Range (Dual Supplies) ±4 ±8 V

Operating Range (Single Supply) +8 +16 V

Quiescent Current T = −40°C to +125°C 3.2 4 mA
TEMPERATURE RANGE

Specified Performance −40 +125 °C

1

The AD8230 can operate as low as G = 2. However, since the differential input range is limited to approximately 750 mV, the AD8230 configured at G < 10 does not

make use of the full output voltage range.

2

Differential source resistance less than 10 kΩ does not result in voltage offset due to input bias current or mismatched series resistors.

= 0 V, RF = 100 kΩ, RG = 1 kΩ (@ TA = 25°C, G = 202, RL = 10 kΩ, unless otherwise noted).

REF

V

OSI

= V

+IN

V

+IN

= 0 V 20 µV

−IN

= V

= 0 V,

−IN

50 nV/°C

T = −40°C to +125°C

1

S

S

2

VCM = 0V 33 pA

, V

, V

IN+

= 0 240 nV/√Hz

IN−

REF

1000 V/V

+V
+V

S

S

V
V

Rev. 0 | Page 4 of 16

AD8230

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage ±8 V, +16 V
Internal Power Dissipation 304 mW
Output Short-Circuit Current 20 mA
Input Voltage (Common-Mode) ±V
Differential Input Voltage ±V

S

S

Storage Temperature −65°C to +150°C
Operational Temperature Range −40°C to +125°C

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 may affect device reliability.

CONNECTION DIAGRAM

1

–V

S

2

+V

S

3

V

1

REF

4

+IN

AD8230

TOP VIEW

(Not to Scale)

Figure 3.

8

V

OUT

7

R

G

6

V

2

REF

5

–IN

05063-001

Specification is for device in free air: SOIC: θ

(4-layer JEDEC

JA

board) = 121°C/W.

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. 0 | Page 5 of 16