31.3 Temperature Indicator Range

The temperature indicator circuit operates in either High or Low range. The High range, selected by setting the TSRNG bit of the FVRCON register, provides a wider output voltage. This provides more resolution over the temperature range. High range requires a higher-bias voltage to operate and thus, a higher VDD is needed. The Low range is selected by clearing the TSRNG bit of the FVRCON register. The Low range generates a lower sensor voltage and thus, a lower VDD voltage is needed to operate the circuit.

The output voltage of the sensor is the highest value at -40°C and the lowest value at +125°C.
  • High Range: The High range is used in applications with the reference for the ADC, VREF = 2.048V. This range may not be suitable for battery-powered applications. The ADC reading (in counts) at 90°C for the high range setting is stored in the DIA Table as parameter TSHR2.
  • Low Range: This mode is useful in applications in which the VDD is too low for high-range operation. The VDD in this mode can be as low as 1.8V. VDD must, however, be at least 0.5V higher than the maximum sensor voltage depending on the expected low operating temperature. The ADC reading (in counts) at 90°C for the low range setting is stored in the DIA Table as parameter TSLR2.