OPA2180

RTD

Pt100

R

105.8k

5

W

(1)

V

OUT

R

60.4k

3

W

R

4.99k

1

W

R

49.1k

2

W

R

1kW

4

1 F

m

1 F

m

REF5050

+15V

In

Out

(5V)

0 C=0V

200 C=5V

°

°

½

OPA2180

-15V

15V

U5

½

OPA2180

15V

-15V

U2

+

VCM

10

V

R

1kW

5

R

1kW

7

R

500 W

G

V

P

OUT

V

N

OUT

U1

INA159

3.3V

V

OUT

Ref1

Ref2

Sense

OPA180, OPA2180, OPA4180

SBOS584D – NOVEMBER 2011 – REVISED MAY 2014

www.ti.com

9.2.2 Discrete INA + Attenuation

The OPA180 can be used as a high-voltage, high-impedance front-end for a precision, discrete instrumentation

amplifier with attenuation. The INA159 provides the attenuation that allows this circuit to easily interface with 3.3-

V or 5-V analog-to-digital converters (ADCs).

Figure 33. Discrete INA + Attenuation for ADC with 3.3-V Supply

9.2.3 RTD Amplifier

The OPA180 is excellent for use in analog linearization of resistance temperature detectors (RTDs). The below

circuit combines the precision of the OPA180 amplifier and the precision reference REF5050 to linearize a Pt100

RTD.

Figure 34. RTD Amplifier with Linearization

20

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