Two temperature sensors with signal-conditioning amplifiers realized in BiCMOS technology

Two temperature sensors realized in BiCMOS technology are described. The fi rst sensor is using, as a temperature sensitive element, an original circui t of threshold extractor. The output of this circuit provides the p-channel transistor threshold voltage that changes with temperature. The second sen sor is a resistive bridge using polysilicon and base-diffused resistors tha t have the temperature coefficients of opposite sign. Both sensors were rea lized with signal-conditioning amplifiers. The sensors characteristics are given for the temperature range of -40 to 150 degrees C. The threshold volt age is not accurately reproducible, yet the sensors temperature characteris tics are linear in the whole temperature range with a slope of 1.8 mV/degre es C that is close to the theoretical one. The characteristics of bridge se nsors are tightly reproducible, close to the theoretical ones, but they sho w essential nonlinearity in the considered temperature range. (C) 1999 Else vier Science S.A. All rights reserved.