Temperature Sensor - NXP Semiconductors MKL27Z128VFM4 Reference Manual

Table of Contents

Functional description

There is an effective limit to the values of offset that can be set

by the user. If the magnitude of the offset is too high, the results

of the conversions will cap off at the limits.

The offset calibration function may be employed by the user to remove application

offsets or DC bias values. OFS may be written with a number in 2's complement format

and this offset will be subtracted from the result, or hardware averaged value. To add an

offset, store the negative offset in 2's complement format and the effect will be an

addition. An offset correction that results in an out-of-range value will be forced to the

minimum or maximum value. The minimum value for single-ended conversions is

0x0000; for a differential conversion it is 0x8000.

To preserve accuracy, the calibrated offset value initially stored in OFS must be added to

the user-defined offset. For applications that may change the offset repeatedly during

operation, store the initial offset calibration value in flash so it can be recovered and

added to any user offset adjustment value and the sum stored in OFS.

23.5.8 Temperature sensor

The ADC module includes a temperature sensor whose output is connected to one of the

ADC analog channel inputs.

The following equation provides an approximate transfer function of the temperature

Equation 2. Approximate transfer function of the temperature sensor

is the voltage of the temperature sensor channel at the ambient temperature.

is the voltage of the temperature sensor channel at 25 °C.

• m is referred as temperature sensor slope in the device data sheet. It is the hot or cold

voltage versus temperature slope in V/°C.

For temperature calculations, use the V

the ADC Electricals table.

KL27 Sub-Family Reference Manual , Rev. 5, 01/2016

and temperature sensor slope values from

Freescale Semiconductor, Inc.