31.4 Estimation of Temperature

This section describes the steps involved in estimating the die temperature, TMEAS:
  1. Obtain the ADC count value of the measured analog voltage: The analog output voltage, VMEAS is converted to a digital count value by the Analog-to-Digital Converter (ADC) and is referred to as ADCMEAS.
  2. Obtain the ADC count value, ADCDIA at 90°C, from the DIA Table. This parameter is TSLR2 for the low range setting or TSHR2 for the high range setting of the temperature indicator module.
  3. Obtain the output analog voltage (in mV) value of the Fixed Reference Voltage (FVR) for 2x setting, from the DIA table. This parameter is referred to as FVRA2X in the DIA Table.
  4. Obtain the value of the temperature indicator voltage sensitivity, parameter Mv, from the “Electrical Specifications” section.

The following equation provides an estimate of the die temperature based on the above parameters:

Equation 31-2. Sensor Temperature
T M E A S = 90 + ( A D C M E A S − A D C D I A ) × F V R A 2 X ( 2 N − 1 ) × M v
Note: Where:

ADCMEAS = ADC reading at temperature being estimated

ADCDIA = ADC reading stored in the DIA

FVRA2X = FVR value stored in the DIA for 2x setting

N = Resolution of the ADC

Mv = Temperature Indicator voltage sensitivity (mV/°C)

Note: It is recommended to take the average of ten measurements of ADCMEAS to reduce noise and improve accuracy.