A 300°C dynamic-feedback instrumentation amplifier

Abstract

A high-temperature instrumentation amplifier that uses dynamic feedback is presented. It realizes dynamic feedback by means of a rotating chain of resistors to compensate for resistor mismatches. An 11/spl times/ dynamic-feedback instrumentation amplifier has been integrated in a standard junction-isolated 1.6-/spl mu/m CMOS process and realizes an average gain error below 25 ppm up to 250/spl deg/C without calibration or trimming. Leakage currents cause additional gain errors at higher temperatures. Nevertheless, even at 300/spl deg/C, this average gain error is still less than 500 ppm.