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

Precision Instrumentation Amplifier

AD8230

Rev. B

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FEATURES

Resistor programmable gain range: 101 to 1000

Supply voltage range: ±4 V to ±8 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 maximum offset voltage (RTI, ±5 V operation)

50 nV/°C maximum offset drift

20 ppm maximum 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 (minimum) 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 101 and 1000, users can adjust the output

offset voltage.

CONNECTION DIAGRAM

8

7

6

5

1

2

3

4

–IN

TOP VIEW

(Not to Scale)

+IN

AD8230

Figure 1. 8-Lead SOIC (R-8)

TEMPERATURE (°C)

150

–50

–30

–10

10

30

50

70

90

110

130

2.0

1.5

1.0

0.5

0

–0.5

–1.0

–1.5

–2.0

Figure 2. Relative Offset Voltage vs. Temperature

2

6

1

7

5

8

4

3

AD8230

–5V

+5V

TYPE K THERMOCOUPLE

0.1µF

284Ω

34.8kΩ

0.1µF

Figure 3. Thermocouple Measurement

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.

input voltage is limited to approximately 750 mV.