STLM20 temperature-to-output transfer function

AN2648

4/15

Figure 4.

Application temperature and voltage ranges

In Equation 1, the slope is –11.69 mV per °C. For the 8-bit ADC, the step size is 5 V/255

steps or 0.019608 V/step. Comparing this to the slope, we get:

This means that, with the temperature sensor connected directly to the ADC, the resolution

is only 1.68°C/step. The smallest temperature increment the ADC can resolve is

1.68°C. This is very coarse resolution.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

- 60

- 40

- 20

0

20

40

60

80

100

Temperature range of interest

Available voltage range

Used voltage range

of application

ai13988

STLM20 full temperature range

Temperature, T (˚C)

C/step

1.677318

C

V/

1169

0

.

0

V/step

0.019608

°

−

=

°

−