9.2.2 Resistance Temperature Detector Interface

Figure 72 illustrates a 3-wire interface circuit for resistance temperature detectors (RTDs). The circuit incorporates analog linearization and has an output voltage range from 0 V to 5 V. The linearization technique employed is described in the Analog linearization of resistance temperature detectors analog application journal. Series and parallel combinations of standard 1% resistor values are used to achieve less than 0.02°C of error over a 200°C temperature span.

Figure 72. A 3-Wire Interface for RTDs With Analog Linearization

Figure 73. Transfer Function of a 3-Wire RTD Interface

Figure 74. Temperature Error Over the Full Temperature Range