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 /spl 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 a 1.5 /spl mu/m BiCMOS process. Average temperature coefficients (TC's) of the negative BGR are measured as 2.4 and 6.7 ppm//spl deg/C, and those of the positive BGR are measured as 3.5 and 8.9 ppm//spl deg/C over the commercial (0/spl sim/70/spl deg/C) and military (-55/spl sim/125/spl deg/C) temperature ranges, respectively. These circuits dissipate 0.37 mW with a single 5 V supply, and occupy 270/spl times/150 /spl mu/m/sup 2/ and 290/spl times/150 /spl mu/m/sup 2/, respectively.<
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