Team,
Can you please help with the below customer question:
We are currently using the TMP64 devices (TMP6431QDECRQ1 to be specific) in our project, and used the Thermistor Design Tool from the TI homepage (https://www.ti.com/tool/TMP6-THERMISTOR-DESIGN), to get a 4th order polynomial equation for this device, and calculating the temperature in degree from the ADC voltage.
-We entered our parameters on the first page (V_bias = 5V, and ADC = 14bits), and tried to verify the equation with the builtin function on sheet “4th order Polynomial TMP vs. Vdc”, to verify the resulting equation.
-However, if we entered 2.5V as Vtemp for example, we thought that we should get the nominal temperature of 25°C @ 47kOhm, to which the 47kOhm thermistor and its 47kOhm bias resistor is designed for.
But if we do this, we get 29.1°C as output temperature of the design tool.
Our question is therefore, if we missed something in the device datasheet, or the design with this Excel tool?
From the sheet “device resistance table”, we also can see that the resistance @25°C is 45.834kOhm, which is not what we expected from the datasheet.
Thanks in advance,
A.