Temperature sensor overview

AN3397

8/24

Doc ID 018809 Rev 1

Equation 1

Solving with values: (4 x 3/(4096 * 1.62 mV/°C) = ±1.80 °C.

3.

The maximum calibration related error is considered to be ±0.25 °C at ambient

temperature. In this situation, the temperature error (±0.25 °C) is linked to the accuracy

of the thermometer.

Total temperature error calculation

Consequently, the total measurement error at 25 °C is the sum of the ADC TUE in °C



(±1.80 °C) and the calibration related error (±0.25 °C) which is ±2.05 °C.

Note:

The linearity error is cancelled at the user calibration point since it is obtained from the

measurement.

By using Thales theorem, we can estimate the temperature error for any point in the

temperature sensor range.

First, ‘I’ (see Figure 1) must be calculated (using Thales theorem).

Solving with values: 0. 5/10 = (24.75 - I)/(85 - I)

Therefore, I = 21.6

An example of the calculation error at 50 °C is as follows:

Solving with values: (50 - 21.6)/(85 - 21.6) = Error(50 °C)/10

Therefore, the calculation error at 50 °C = ±4.47 °C.

ADC TUE (°C)

TUE

V

REF

12bits ADC



------------------------------------







avg_slope

------------------------------------------------------------

=

Error (25 °C)

Error (90 °C)

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IA

IC

------

=

IB

IC

------

Error (50 °C)

Error (85 °C)

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=