Using the Temperature Sensor TC1047A with MCU
Your sensor has an input range of -40°C to +125°C producing a voltage range of 0.1V - 1.75V

There is a scaling circuit which scales and offsets this voltage to 0V @ -40°C to 5V @ 125°C
- that is a 165°C range of temperature over a 5V range in voltage

The A2D produce a reading of 0 for a 0V input and 1023 for 5V input - that is a range of 1024

so 1024 / 165 = 6.206
and a 40°C offset

To convert bits to °C you take the A2D reading divide by 6.206 and subtract 40.