SLAU873D January 2023 – October 2024
The LaunchPad kit includes a 10k linear thermistor (PTC), the TMP6131. Figure 2-8 shows the circuit. The PTC is in a low-side configuration with a 10kΩ 10ppm pullup resistor. The default position of the jumper in the header (1-2 position) connects this circuit directly to the ADC. In this mode, the output voltage is approximately 1.6V at room temperature.
The jumper can also be set to the 2-3 position to allow an OPA connection to the thermistor. The OPA output can be connected internally, through software, to the negative OPA terminal. This allows the OPA to be used as a buffer for the thermistor with an internal connection to an ADC channel for sampling. If an external connection or additional biasing or filtering is wanted, then the passives shown in Figure 2-8 need to be populated.