AN3397

Temperature sensor overview

Doc ID 018809 Rev 1

7/24

Figure 1.

Temperature sensor engineering tolerance

1.5

Temperature sensor error estimation

Once the temperature sensor has been correctly calibrated with both factory and user

calibration points, the engineering tolerance of the temperature measurement is significantly

improved (see area between the two black lines in Figure 1.

The temperature measurement error is caused by the following:

●

Temperature sensor linearity

●

ADC total unadjusted error (TUE)

●

Calibration related error

Figure 1 shows that the temperature error is minimized in the neighbourhood of the user

calibration point and that it slightly increases with distance from this point.

Temperature error calculation

The temperature measurement error can be calculated as explained below. Note that the

user calibration point needs to be defined before the calculation.

1.

The maximum linearity error is ±2 °C (see STM8L15xxx datasheets).

2.

To calculate the temperature measurement error linked to the ADC total unadjusted error,

use Equation 1.

A

C

B

I

TS voltage

V90

V50

0

25±0.25

50

85

95

T °C

V90 tolerance

MS30515V1

Error 0°C

Error 25°C

Error 50°C

Error V90

User calibration point

Max slope

Min slope