8.5.1 Resistance Temperature Detector Interface

Figure 71 illustrates a 3-wire interface circuit for resistance temperature detectors (RTDs). The circuit incorporates analog linearization and has an output voltage range from 0 to 5 V. The linearization technique employed is described in Analog linearization of resistance temperature detectors. 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 71. A 3-Wire Interface for RTDs With Analog Linearization

Figure 72. Transfer Function of 3-Wire RTD Interface

Figure 73. Temperature Error Over Full Temperature Range