Temperature measurement circuit using AD7714

The temperature measurement circuit composed of AD7714 and thermocouple is shown in the figure. In this application, AD7714 works in buffer mode, allowing decoupling capacitors to be connected at the front end to filter out the noise on the thermocouple leads. In buffer mode, the common mode range of AD7714 is narrow. In order to make the differential voltage of the thermocouple within the appropriate common mode voltage range, the AIN2 input of AD7714 should be biased to a +2.5V reference voltage.