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 β 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 μm BiCMOS process. Average temperature coefficients (TC´s) of the negative BGR are measured as 2.4 and 6.7 ppm/°C, and those of the positive BGR are measured as 3.5 and 8.9 ppm/°C over the commercial (0~70°C) and military (-55~125°C) temperature ranges, respectively. These circuits dissipate 0.37 mW with a single 5 V supply, and occupy 270×150 μm² and 290×150 μm² , respectively