A monolithic conditioner for thermocouple signals

The authors discusses a monolithic signal conditioner for direct thermocouple input which provides gain, common-mode signal rejection, and cold-junction compensation. It provides 50 to 1 ambient temperature rejection and a nominal 10 mV//spl deg/C output range. It operates on as little as 800 /spl mu/W, provides a thermocouple fault alarm and has provision for use as a set-point feedback controller as well as for signal measurements. The circuit is fabricated on a standard linear IC process and uses laser-wafer-trimmed thin-film resistors to achieve 1/spl deg/C temperature calibration.