EXPONENTIAL CURVATURE-COMPENSATED BICMOS BANDGAP REFERENCES

An exponential curvature compensation technique for bandgap references (BGR's) which exploits the temperature characteristics of the current gain beta of a bipolar transistor is described. This technique requires no additional circuits for the curvature compensation; only a size adjustment of a bias transistor in a conventional first-order compensated BGR is required. Positive and negative versions of the exponential curvature-compensated BGR have been fabricated using 1.5-mu m BiCMOS process. Average temperature coefficients (TC's) of the negative BGR are measured as 2.4 and 6.7 ppm/degrees C, and those of the positive BGR are measured as 3.5 and 8.9 ppm/degrees C over the commercial (0 similar to 70 degrees C) and military (-55 similar to 125 degrees C) temperature ranges, respectively. These circuits dissipate 0.37 mW with a 5-V single supply, and occupy 270 x 150 mu m(2) and 290 x 150 mu m(2), respectively.