How accurate is the NXP LPC546XX temperature sensor?

[lukea]

Hi,

The NXP LPC546xx  datasheet has the below text in section 7.2.2 Temperature sensor:

        The output voltage varies inversely with device temperature with an absolute accuracy of better than ±5 deg C over the full temperature range (-40 deg C to +105 deg C).
        The temperature sensor is only approximately linear with a slight curvature.
        The output voltage is measured over different ranges of temperatures and fit with linear-least-square lines.

But also in section 12.3 (Temperature sensor as well) there is a table that shows accuracy as Max 3.7 Degrees C.
Does anyone know which is correct?
Or is it a case of linearity error on top of +/- 5 Deg C making it +/- 8.7 Deg C?

Thank you

Luke

[xiangjun_rong]

Hi,

As you know that we get the slop and offset after Linear-Least-Square (LLS) fit, the m is -2.05, the offset is 584.

This is the formula to figure out the temperature:

sensor output voltage=-2.4mv/Degree*temperature+584mV

With above formula, we can guarantee that the error is less than 3.7 degree in the -40 to +105 degree range.

Hope it can help you

BR

Xiangjun Rong