Dear Sir ,
I am measuring the temperature through NTC . I prefer the TI Design Analog Engineer's Circuit: Amplifiers SBOA323–December 2018.Temperature sensing with NTC circuit. I gone through the design in which measuring range select -20 to 105 Degree . Based on Selected NTC value we found the R1 7.54K . We selected minimum output is 0.5V & Maximum Output 2.7V .
But As per calculation we found at -20 Degree 0.237 & at 105 Degree Found 3.07V . Reference voltage i set thorough voltage divider from 3.3V . That is found 1.56V .
Calculate the gain found 0.78 . Then according R3 Found 220R with respect to R1 1K .Actual 1.22 .
As per this gain value I am not able to found the output as desired after gain select .
Please suggest .